CA2978460A1 - Load bearing direct drive fan system with variable process control - Google Patents

Abstract

The present invention is directed to a load bearing direct-drive system for driving a fan in a cooling system such as a wet-cooling tower, air-cooled heat exchanger, HVAC system, hybrid cooling tower, mechanical tower or chiller system. The present invention includes a variable process control system that is based on the integration of key features and characteristics such as tower thermal performance, fan speed and airflow, motor torque, fan pitch, fan speed, fan aerodynamic properties, and pump flow. The variable process control system processes feedback signals from multiple locations in order to control a high torque, low variable speed, load bearing motor to drive the fan.

Description

1 LOAD BEARING, DIRECT DRIVE FAN SYSTEM

2 WITH VARIABLE PROCESS CONTROL

3

4 CROSS-REFERENCE TO RELATED APPLICATIONS:
This application is a continuation-in-part of U.S. application no. 14/352,050, filed 6 April 15, 2014. The entire disclosure of the aforesaid U.S. application no. 14/352,050 is 7 hereby incorporated by reference.
8 This application also claims the benefit of U.S. provisional application no.
9 62/113,277, filed February 6, 2015. The entire disclosure of application no. 62/113,277 is hereby incorporated by reference.

12 TECHNICAL FIELD:
13 The present invention generally relates to a method and system for efficiently 14 managing the operation and performance of cooling towers, air-cooled heat exchangers (ACHE), HVAC, and mechanical towers and chillers.

17 BACKGROUND ART:
18 Industrial cooling systems, such as wet-cooling towers and air-cooled heat 19 exchangers (ACHE), are used to remove the heat absorbed in circulating cooling water used in power plants, petroleum refineries, petrochemical and chemical plants, natural 21 gas processing plants and other industrial facilities. Wet-cooling towers and ACHEs are 22 widely used in the petroleum refining industry. Refining of petroleum depends upon the 23 cooling function provided by the wet-cooling towers and air-cooled heat exchangers.

1 Refineries process hydrocarbons at high temperatures and pressures using processes 2 such as Liquid Catalytic Cracking and Isomerization. Cooling water is used to control 3 operating temperatures and pressures. The loss of cooling water circulation within a 4 refinery can lead to unstable and dangerous operating conditions requiring an immediate shut down of processing units. Wet-cooling towers and ACHEs have 6 become "mission critical assets" for petroleum refinery production. Thus, cooling 7 reliability has become mission critical to refinery safety and profit and is affected by 8 many factors such as environmental limitations on cooling water usage, environmental 9 permits and inelastic supply chain pressures and variable refining margins. As demand for high-end products such as automotive and aviation fuel has risen and refining 11 capacity has shrunk, the refineries have incorporated many new processes that extract 12 hydrogen from the lower value by-products and recombined them into the higher value 13 products. These processes are dependent on cooling to optimize the yield and quality 14 of the product. Over the past decade, many refineries have been adding processes that reform low grade petroleum products into higher grade and more profitable products 16 such as aviation and automotive gasoline. These processes are highly dependent upon 17 the wet-cooling towers and ACHEs to control the process temperatures and pressures 18 that affect the product quality, process yield and safety of the process. In addition, 19 these processes have tapped a great deal of the cooling capacity reserve in the towers leaving some refineries "cooling limited" on hot days and even bottlenecked.
ACHE
21 cooling differs from wet cooling towers in that ACHEs depend on air for air cooling as 22 opposed to the latent heat of vaporization or "evaporative cooling".
Most U.S. refineries 23 operate well above 90% capacity and thus, uninterrupted refinery operation is critical to 1 refinery profit and paying for the process upgrades implemented over the last decade.
2 The effect of the interruption in the operation of cooling units with respect to the impact 3 of petroleum product prices is described in the report entitled "Refinery Outages:
4 Description and Potential Impact On Petroleum Product Prices", March 2007, U.S.
Department of Energy.
6 Typically, a wet cooling tower system comprises a basin which holds cooling 7 water that is routed through the process coolers and condensers in an industrial facility.
8 The cool water absorbs heat from the hot process streams that need to be cooled or 9 condensed, and the absorbed heat warms the circulating water. The warm circulating water is delivered to the top of the cooling tower and trickles downward over fill material ii inside the tower. The fill material is configured to provide a maximum contact surface, 12 and maximum contact time, between the water and air. As the water trickles downward 13 over the fill material, it contacts ambient air rising up through the tower either by natural 14 draft or by forced draft using large fans in the tower. Many wet cooling towers comprise a plurality of cells in which the cooling of water takes place in each cell in accordance 16 with the foregoing technique. Cooling towers are described extensively in the treatise 17 entitled "Cooling Tower Fundamentals", second edition, 2006, edited by John C.
18 Hensley, published by SPX Cooling Technologies, Inc.
19 Many wet cooling towers in use today utilize large fans, as described in the foregoing discussion, to provide the ambient air. The fans are enclosed within a fan 21 stack which is located on the fan deck of the cooling tower. Fan stacks are typically 22 configured to have a parabolic shape to seal the fan and add fan velocity recovery. In 23 other systems, the fan stack may have a cylindrical shape. Drive systems are used to 1 drive and rotate the fans. The efficiency and production rate of a cooling tower is 2 heavily dependent upon the efficiency of the fan drive system. The duty cycle required 3 of the fan drive system in a cooling tower environment is extreme due to intense 4 humidity, poor water chemistry, potentially explosive gases and icing conditions, wind shear forces, corrosive water treatment chemicals, and demanding mechanical drive 6 requirements. In a multi-cell cooling tower, such as the type commonly used in the 7 petroleum industry, there is a fan and fan drive system associated with each cell. Thus, 8 if there is a shutdown of the mechanical fan drive system associated with a particular 9 cell, then that cell suffers a "cell outage". A cell outage will result in a decrease in the production of refined petroleum. For example, a "cell outage" lasting for only one day 11 can result in the loss of thousands of refined barrels of petroleum. If numerous cells 12 experience outages lasting more than one day, the production efficiency of the refinery 13 can be significantly degraded. The loss in productivity over a period of time can be 14 measured as a percent loss in total tower-cooling potential. As more cell outages occur within a given time frame, the percent loss in total tower-cooling potential will increase.
16 This, in turn, will decrease product output and profitability of the refinery and cause an 17 increase in the cost of the refined product to the end user. It is not uncommon for 18 decreases in the output of petroleum refineries, even if slight, to cause an increase in 19 the cost of gasoline to consumers. There is a direct relationship between cooling BTUs and Production in barrels per day (BBL/Day).
21 One prior art drive system commonly used in wet-cooling towers is a complex, 22 mechanical fan drive system that utilizes a motor that drives a drive train. The drive 23 train is coupled to a gearbox, gear-reducer or speed-reducer which is coupled to and 1 drives the fan blades. Referring to FIG. 1, there is shown a portion of a wet-cooling 2 tower 1. Wet-cooling tower 1 utilizes the aforesaid prior art fan drive system. Wet 3 cooling tower 1 has fan stack 2 and fan 3. Fan 3 has fan seal disk 4, fan hub 5A and 4 fan blades 5B. Fan blades 5B are connected to fan hub 5A. The prior art fan drive system includes a gearbox 6 that is coupled to drive shaft 7 which drives gearbox 6.
6 The prior art fan drive system includes induction motor 8 which rotates drive shaft 7.
7 Shaft couplings, not shown but well known in the art, are at both ends of drive shaft 7.
8 These shaft couplings couple the draft shaft 7 to the gearbox 6 and to induction motor 8.
9 Wet-cooling tower 1 includes fan deck 9 upon which sits the fan stack 2.
Gearbox 6 and induction motor 9 are supported by a ladder frame or torque tube (not shown) but ii which are well known in the art. Vibration switches are typically located on the ladder 12 frame or torque tube. One such vibration switch is vibration switch 8A
shown in FIG. 1.
13 These vibration switches function to automatically shut down a fan that has become 14 imbalanced for some reason. This prior art fan drive system is subject to frequent outages, a less-than-desirable MTBF (Mean Time Between Failure), and requires 16 diligent maintenance, such as regular oil changes, in order to operate effectively.
17 Coupling and shaft alignment are critical and require experienced craft labor. One 18 example of a mechanical drive system used in the prior art gearbox-type fan drive 19 utilizes five rotating shafts, eight bearings, three shaft seals (two at high speed), and four gears (two meshes). This drive train absorbs about 3% of the total power.
21 Although this particular prior art fan drive system may have an attractive initial low cost, 22 cooling tower end-users found it necessary to purchase heavy duty and oversized 23 components such as composite gearbox shafts and couplings in order to prevent

5

6 1 breakage of the fan drive components especially when attempting across-the-line starts.
2 Many cooling tower end-users also added other options such as low-oil shutdown, anti-3 reverse clutches and oil bath heaters. Thus, the life cycle cost of the prior art 4 mechanical fan drive system compared to its initial purchase price is not equitable.
Once the end user has purchased the more expensive heavy duty and oversized 6 components, the reliability of the prior art fan drive system is still quite poor even after

7 they perform all the expensive and time consuming maintenance. Thus, this prior art

8 gearbox-type drive system has a low, initial cost, but a high cycle cost with poor

9 reliability. In a multi-cell cooling tower, such as the type commonly used in the petroleum industry, there is a fan and prior art mechanical fan drive system associated ii with each cell. Thus, if there is a shutdown of the mechanical fan drive system 12 associated with a particular cell, then that cell suffers a "cell outage" which was 13 described in the foregoing description. The loss in productivity over a period of time due 14 to the poor reliability of the prior art mechanical fan drive systems can be measured as a percent loss in refinery production (bbls/day). In one currently operating cooling tower 16 system, data and analysis has shown that the loss of one cell is equated to the loss of 17 2,000 barrels per day.
18 The problems and inefficiencies of gear-box type drive systems used to drive 19 paper machines has been documented in the article entitled "Permanent Magnet Motors Eliminate Gearboxes", by Jouni Ikaheimo, published in ABB Review, January 1, 21 2002. The article describes replacing gear-box type drive systems for paper machines 22 with permanent magnet motors. However, the permanent magnet motors described in 23 this article are not load bearing motors and cannot bear the loads of a cooling tower fan 1 or the loads of a fan in an air-cooled heat exchanger tower. Furthermore, this article 2 neither discloses the problems associated with the use of gear-box type drive systems 3 in wet cooling towers nor discloses a solution for such problems.
4 Other types of prior art fan drive systems, such as V-belt drive systems, also exhibit many problems with respect to maintenance, MTBF and performance and do not 6 overcome or eliminate the problems associated with the prior art gearbox-type fan drive 7 systems. One attempt to eliminate the problems associated with the prior art gearbox-8 type fan drive system was the prior art hydraulically driven fan systems.
Such a system 9 is described in U.S. Patent No. 4,955,585 entitled "Hydraulically Driven fan System for Water Cooling Tower".
ii Air Cooled Heat Exchangers (ACHE) are well known in the art and are used for 12 cooling in a variety of industries including power plants, petroleum refineries, 13 petrochemical and chemical plants, natural gas processing plants, and other industrial 14 facilities that implement energy intensive processes. ACHE exchangers are used typically where there is lack of water, or when water-usage permits cannot be obtained.
16 ACHEs lack the cooling effectiveness of "Wet Towers" when compared by size (a.k.a.
17 footprint). Typically, an ACHE uses a finned-tube bundle. Cooling air is provided by 18 one or more large fans. Usually, the air blows upwards through a horizontal tube 19 bundle. The fans can be either forced or induced draft, depending on whether the air is pushed or pulled through the tube bundle. Similar to wet cooling towers, fan-tip speed 21 typically does not exceed 12,000 feet per minute for aeromechanical reasons and may 22 be reduced to obtain lower noise levels. The space between the fan(s) and the tube 23 bundle is enclosed by a fan stack that directs the air (flow field) over the tube bundle 1 assembly thereby providing cooling. The whole assembly is usually mounted on legs or 2 a pipe rack. The fans are usually driven by a fan drive assembly that uses an electric 3 motor. The fan drive assembly is supported by a steel, mechanical drive support 4 system. Vibration switches are typically located on the structure that supports the fan assembly. These vibration switches function to automatically shut down a fan that has 6 become imbalanced for some reason. Airflow is very important in ACHE
cooling to 7 ensure that the air has the proper "flow field" and velocity to maximize cooling.
8 Turbulence caused by current fan gear support structure can impair cooling efficiency.
9 Therefore, mass airflow is the key parameter to removing heat from the tube and bundle system. ACHE cooling differs from wet cooling towers in that ACHEs depend on air for 11 air cooling as opposed to the latent heat of vaporization or "evaporative cooling".
12 Prior art ACHE fan drive systems use any one of a variety of fan drive 13 components. Examples of such components include electric motors, steam turbines, 14 gas or gasoline engines, or hydraulic motors. The most common drive device is the electric motor. Steam and gas drive systems have been used when electric power is 16 not available. Hydraulic motors have also been used with limited success. Specifically, 17 although hydraulic motors provide variable speed control, they have relatively low 18 efficiencies. Motor and fan speed are sometimes controlled with variable frequency 19 drives with mixed success. The most commonly used speed reducer is the high-torque, positive type belt drive, which uses sprockets that mesh with the timing belt cogs. They 21 are used with motors up to 50 or 60 horsepower, and with fans up to about 18 feet in 22 diameter. Banded V-belts are still often used in small to medium sized fans, and gear 23 drives are used with very large motors and fan diameters. Fan speed is set by using a 1 proper combination of sprocket or sheave sizes with timing belts or V-belts, and by 2 selecting a proper reduction ratio with gears. In many instances, right-angle gear boxes 3 are used as part of the fan drive system in order to translate and magnify torque from an 4 offset electrical motor. However, belt drives, pulleys and right-angle gear boxes have poor reliability. The aforesaid complex, prior art mechanical drive systems require 6 stringent maintenance practices to achieve acceptable levels of reliability. In particular, 7 one significant problem with ACHE fan systems is the poor reliability of the belt due to 8 belt tension. A common practice is to upgrade to "timing belts" and add a tension 9 system. One technical paper, entitled "Application of Reliability Tools to Improve V-Belt Life on Fin Fan Cooler Units", by Rahadian Bayu of PT, Chevron Pacific Indonesia, ii Riau, Indonesia, presented at the 2007 International Applied Reliability Symposium, 12 addresses the reliability and efficiency of V-belts used in many prior art fan drive 13 systems. The reliability deficiencies of the belt and pulley systems and the gear reducer 14 systems used in the ACHE fan drive systems often result in outages that are detrimental to mission critical industries such as petroleum refining, petro-chemical, power 16 generation and other process intensive industries dependent on cooling.
Furthermore, 17 the motor systems used in the ACHE fan drive systems are complex with multiple 18 bearings, auxiliary oil and lubrications systems, complex valve systems for control and 19 operation, and reciprocating parts that must be replaced at regular intervals. Many petroleum refineries, power plants, petrochemical facilities, chemical plants and other 21 industrial facilities utilizing prior art ACHE fan drive systems have reported that poor 22 reliability of belt drive systems and right-angle drive systems has negatively affected 23 production output. These industries have also found that service and maintenance of 1 the belt drive and gearbox system are major expenditures in the life cycle cost, and that 2 the prior art motors have experienced failure due to the incorrect use of high pressure 3 water spray. The duty cycle required of an ACHE fan drive system is extreme due to 4 intense humidity, dirt and icing conditions, wind shear forces, water washing (because the motors are not sealed, sometime they get sprayed by operators to improve cooling 6 on hot days), and demanding mechanical drive requirements.
7 In an attempt to increase the cooling performance of ACHE cooling systems, 8 some end-users spray water directly on the ACHE system to provide additional cooling 9 on process limiting, hot days. Furthermore, since fan blades can become "fouled" or dirty in regular service and lose performance, many end-users water-wash their ACHE
11 system to maintain their cooling performance. However, directly exposing the ACHE
12 system to high pressure water spray can lead to premature maintenance and/or failure 13 of system components, especially since prior art drive systems are typically open 14 thereby allowing penetration by water and other liquids. Thus, the efficiency and production rate of a process is heavily dependent upon the reliability of the ACHE
16 cooling system and its ability to remove heat from the system.
17 Prior art fan systems have further drawbacks. Most of the currently installed fleet 18 of cooling tower fans operates continuously at 100% speed. For a small percentage of 19 applications, variable frequency drives ("VFD") of Adjustable Speed Drives have been applied to an induction motor to simulate variable speed. However, the application of 21 VFDs to induction motors has not been overly successful and not implemented on a 22 wide scale due to poor success rates. In some cases this may also involve a two-speed 23 induction motor. These applications have not been widely installed by end-users. In 1 some cases, end-users have installed VFDs solely to provide "soft starts"
to the system 2 thereby avoiding "across the line starts" that can lead to failure or breakage of the 3 gearbox system when maximum torque is applied to the system at start-up.
This issue 4 is further exacerbated by "fan windmilling" which occurs when the fan turns in reverse due to the updraft force of the tower on the pitch of the fan. Windmilling of the fan is not 6 allowed due to the lubrication limitation of gearboxes in reverse and requires the 7 addition of an anti-reverse mechanism.
8 Prior art variable speed induction motors are reactive to basin temperature and 9 respond by raising the fan to 100% fan tip speed until basin temperature demand is met and then reducing the speed to a predetermined set speed which is typically 85% fan tip ii speed. Such systems utilize lagging feedback loops that result in fan speed oscillation, 12 instability and speed hunting which consumes large amounts of energy during abrupt 13 speed changes and inertial changes which results in premature wear and failure of gear 14 train parts that are designed for single speed, omni-direction operation.
Induction motors in variable speed duty require extra insulation, additional 16 windings and larger cooling fans for part-load cooling which increases the cost and size.
17 Application of induction motors on variable speed fans requires that the motor be able to 18 generate the required torque to turn the fan to speed at part-load operation which can 19 also require the motor to be larger than for a steady state application and thus increase the cost and size. In these variable speed fan systems, the fan speed is controlled by 21 the basin temperature set point. This means that fan speed will increase according to a 22 set algorithm when the basin temperature exceeds a temperature set point in order to 23 cool the basin water. Once the basin temperature set point has been satisfied the fan 1 speed will be reduced according to the programmed algorithms.
Furthermore, motors 2 and gearboxes are applied without knowledge of the cooling tower thermal performance 3 and operate only as a function of the basin temperature set point which results in large 4 speed swings of the fan wherein the fan speed is cycled from minimum fan speed to maximum fan speed over a short period of time. The speed swings that occur at 6 maximum fan acceleration consume significant amounts of energy.

Typical prior art gearboxes are designed for one-way rotation as evidenced by 8 the lube system and gear mesh design. These gearboxes were never intended to work 9 in reverse. In order to achieve reverse rotation, prior art gearboxes were modified to include additional lube pumps in order to lubricate in reverse due to the design of the oil ii slinger lubrication system which is designed to work in only one direction. These lube 12 pumps are typically electric but can also be of other designs. The gear mesh of the 13 gearbox is also a limiting factor for reverse rotation as the loading on the gear mesh is 14 not able to bear the design load in reverse as it can in forward rotation. Typically, the modified gearboxes could operate in reverse at slow speed for no more than two 16 minutes. End users in colder climates that require reverse rotation for de-icing the 17 cooling tower on cold days have reported numerous failures of the gearbox drive train 18 system. In addition, most operators have to manually reverse the system on each cell 19 which may include an electrician. Since the gearbox and lubrication system are designed for one-way rotation typically at 100% fan speed, fan braking, gear train inertia 21 and variable speed duty will accelerate wear and tear on the gearbox, drive shaft and 22 coupling components as the inertial loads are directly reacted into the drive train, 23 gearbox and motor.

1 VFDs have been and are being applied to induction motors and fan gearbox 2 systems with the hope of saving energy. However, these modifications require more 3 robust components to operate the fan based upon the basin temperature set point. The 4 DOE (Department of Energy) reports that the average energy savings of such applications is 27%. This savings is directly proportional to the fan laws and the 6 reduced loading on the system as opposed to motor efficiency, which for an induction 7 motor, drops off significantly in part-load operation.
8 Currently operating cooling towers typically do not use expensive condition-9 monitoring equipment that has questionable reliability and which has not been widely accepted by the end users. Vibration safety in prior art fan systems is typically achieved ii by the placement of vibration switches on the ladder frame near the motor. An example 12 of such a vibration switch is vibration switch 8A shown in FIG. 1. These vibration 13 switches are isolated devices and are simply on-off switches that do not provide any 14 kind of external signals or monitoring. These vibration switches have poor reliability and are poorly applied and maintained. Thus, these vibration switches provide no signals or 16 information with respect to fan system integrity. Therefore, it is not possible to 17 determine the source or cause of the vibrations. Such vibration switches are also 18 vulnerable to malfunction or poor performance and require frequent testing to assure 19 they are working. The poor reliability of these vibration switches and their lack of fidelity to sense an impeding blade failure continues to be a safety issue.
21 In prior art multi-cell cooling systems that utilize a plurality fans with gearbox 22 drives, each fan is operated independently at 100%, or variable speed controlled 23 independently by the same algorithm. Cooling towers are typically designed at one 1 design point: maximum hot day temperature, maximum wet-bulb temperature and thus 2 operate the fans at 100% steady state to satisfy the maximum hot day temperature, 3 maximum wet-bulb temperature design condition, regardless of environmental 4 conditions.
Current practice (CTI and ASME) attempts to measure the cooling tower 6 performance to a precision that is considered impractical for an operating system that is 7 constantly changing with the surrounding temperature and wet-bulb temperature. Most 8 refinery operators operate without any measure of performance and therefore wait too 9 long between service and maintenance intervals to correct and restore the performance of the cooling tower. It is not uncommon for some end-users to operate the tower to ii failure. Some end-users test their cooling towers for performance on a periodic basis, 12 typically when a cooling tower is exhibiting some type of cooling performance problem.
13 Such tests can be expensive and time consuming and typically normalize the test data 14 to the tower design curve. Furthermore, these tests do not provide any trending data (multiple test points), load data or long-term data to establish performance, 16 maintenance and service criteria. For example, excessive and wasted energy 17 consumption occurs when operating fans that cannot perform effectively because the fill 18 is clogged thus allowing only partial airflow through the tower. Poor cooling 19 performance results in degraded product quality and/or throughput because reduced cooling is negatively affecting the process. Poor cooling tower performance can result 21 in unscheduled downtime and interruptions in production. In many prior art systems, it 22 is not uncommon for end-users to incorrectly operate the cooling tower system by 23 significantly increasing electrical power to the fan motors to compensate for a clogged 1 tower or to increase the water flow into the tower to increase cooling when the actual 2 corrective action is to replace the fill in the tower. Poor cooling tower performance can 3 lead to incorrect operation and has many negative side effects such as reduced cooling 4 capability, poor reliability, excessive energy consumption, poor plant performance, and decrease in production and safety risks.
6 Therefore, in order to prevent supply interruption of the inelastic supply chain of 7 refined petroleum products, the reliability and subsequent performance of wet-cooling 8 towers and ACHE cooling systems must be improved and managed as a key asset to 9 refinery safety, production and profit.
What is needed is a method and system that allows for the efficient operation ii and management of fans in wet-cooling towers and dry-cooling applications.

13 DISCLOSURE OF THE INVENTION:
14 In one aspect, the present invention is directed to a system and method for efficiently managing the operation of fans in a cooling tower system including wet-16 cooling towers, air-cooled heat exchangers (ACHE), mechanical towers, hybrid cooling 17 towers, hybrid heat exchangers, HVAC systems and chillers. The present invention is 18 based on the integration of the key features and characteristics such as (1) tower 19 thermal performance, (2) fan speed and airflow, (3) motor torque, (4) fan pitch, (5) fan speed, (6) fan aerodynamic properties, and (7) pump flow.
21 The present invention is directed to a load bearing, direct drive fan system and 22 variable process control system for efficiently operating a fan in a wet-cooling tower, air-23 cooled heat exchanger (ACHE), HVAC system, mechanical tower, hybrid cooling tower, 1 hybrid heat exchanger and chiller. The present invention is based on the integration of 2 the key characteristics such as tower thermal performance, fan speed and airflow, 3 motor torque, fan pitch, fan speed, fan aerodynamic properties, and pump flow rate. As 4 used herein, the term "pump flow rate" refers to the flow rate of cooled process liquids that are pumped from the cooling tower for input into an intermediate device, such as 6 condenser, and then to the process, then back to the intermediate device and then back 7 to the cooling tower. The present invention uses a variable process control system 8 wherein feedback signals from multiple locations are processed in order to control high-9 torque, low variable speed, load bearing motors that drive the fans and pumps. Such feedback signals represent certain operating conditions including motor temperature, ii basin temperature, vibrations and pump flow-rate. Thus, the variable process control 12 system continually adjust motor RPM, and hence fan and pump RPM, as the operators 13 or users change or vary turbine back-pressure set point, condenser temperature set 14 point process signal (e.g. crude cracker), and plant part-load setting.
The variable process control processes these feedback signals to optimize the plant for cooling and 16 to prevent equipment (turbine) failure or trip. The variable process control alerts the 17 operators for the need to conduct maintenance actions to remedy deficient operating 18 conditions such as condenser fouling. The variable process control of the present 19 invention increases cooling for cracking crude and also adjusts the motor RPM, and hence fan and pump RPM, accordingly during plant part-load conditions in order to save 21 energy.
22 In accordance with the present invention, a load bearing, direct-drive system is 23 used to rotate the fan. The load bearing, direct-drive system comprises a high-torque, 1 low variable speed, load bearing electric motor. The high-torque, low variable speed, 2 load bearing electric motor has a rotatable shaft that is directly connected to fan or fan 3 hub. In one embodiment, the high-torque, low variable speed, load bearing electric 4 motor comprises a permanent magnet motor. In another embodiment, the high-torque, low variable speed, load bearing electric motor comprises a synchronous reluctance 6 motor. In other embodiments, other types of high-torque, low variable speed, load 7 bearing electric motors are used.
8 The variable process control system of the present invention comprises a 9 computer system that comprises a data acquisition device, referred to as DAQ device 200 in the ensuing description. The computer system further comprises an industrial 11 computer, referred to as industrial computer 300 in the ensuing description.
12 The variable process control system of the present invention includes a plurality 13 of variable speed pumps, wherein each variable speed pumps comprises a high torque, 14 low variable speed, load bearing, electric motor. The variable process control system further comprises a Variable Frequency Drive (VFD) device which comprises a plurality 16 of individual Variable Frequency Drives. Each Variable Frequency drive is dedicated to 17 one high torque, low variable speed, load bearing electric motor.
Therefore, one 18 Variable Frequency Drive corresponds to the high torque, low variable speed, load 19 bearing electric motor that drives the fan, and each of the remaining Variable Frequency Drives is dedicated to controlling the high torque, low variable speed, load bearing 21 electric motor of a corresponding variable speed pump. Thus, each motor is controlled 22 independently. In an alternate embodiment, Variable Speed Drives (VSD) are used 23 instead of variable frequency drive devices.

1 The variable process control system of the present invention provides adaptive 2 and autonomous variable speed operation of the fan and pump with control, supervision 3 and feedback with operator override. A computer system processes data including 4 cooling tower basin temperature, current process cooling demand, condenser temperature set-point, tower aerodynamic characteristics, time of day, wet-bulb 6 temperature, vibration, process demand, environmental stress (e.g. wind speed and 7 direction) and historical trending of weather conditions to control the variable speed fan 8 in order to control the air flow through the cooling tower and meet thermal demand. The 9 Variable Process Control System anticipates process demand and increases or decreases the fan speed in pattern similar to a sine wave over a twenty four (24) hour I period. The Variable Process Control System accomplishes this by using a Runge-12 Kutter algorithm (or similar algorithm) that analyzes historical process demand and 13 environmental stress as well as current process demand and current environmental 14 stress to minimize the energy used to vary the fan speed. This variable process control of the present invention is adaptive and learns the process cooling demand by historical 16 trending as a function of date and time. The operators of the plant input basin 17 temperature set-point data into the Plant DCS (Distributed Control System). The basin 18 temperature set-point data can be changed instantaneously to meet additional cooling 19 requirements such as cracking heavier crude, maintaining vacuum backpressure in a steam turbine, preventing heat exchanger fouling or derating the plant to part-load. In 21 response to the change in the basin temperature set-point, the variable process control 22 system of the present invention automatically varies the rotational speed of the high 23 torque, low variable speed, load bearing electric motor, and hence the rotational speed 1 of the fan, so that the process liquids are cooled such that the temperature of the liquids 2 in the collection basin is substantially the same as the new basin temperature set-point.
3 This feature is referred to herein as "variable process control".
4 In an alternate embodiment, a condenser temperature set-point is inputted into the plant Distributed Control System (DCS) by the operators. The DCS is in electronic 6 signal communication with the Data Acquisition (DAQ) Device and/or Industrial 7 Computer of the Variable Process Control System of the present invention.
The Data 8 Acquisition device then calculates a collection basin temperature set-point that is 9 required in order to meet the condenser temperature set-point. The Variable Process Control system then operates the fan and variable speed pumps to maintain a collection ii basin temperature that meets the condenser temperature set-point inputted by the 12 operators.
13 The variable process control system of the present invention utilizes variable 14 speed motors to drive fans and pumps to provide the required cooling to the industrial process even as the environmental stress changes. Process parameters, including but 16 not limited to, temperatures, pressures and flow rates are measured throughout the 17 system in order to monitor, supervise and control cooling of liquids (e.g. water) used by 18 the industrial process. The variable process control system continually monitors cooling 19 performance as a function of process demand and environmental stress to determine available cooling capacity that can be used for additional process production (e.g.
21 cracking of crude, hot-day turbine output to prevent brown-outs) or identify cooling tower 22 expansions. The variable process control system automatically adjusts cooling capacity 23 when the industrial process is at part-load conditions (e.g. outage, off-peak, cold day, 1 etc.) 2 The present invention is applicable to multi-cell cooling towers. In a multi-cell 3 system, the speed of each fan in each cell is varied in accordance with numerous 4 factors such as Computational Liquid Dynamic Analysis, thermal modeling, tower configuration, environmental conditions and process demand.
6 The core relationships upon which the system and method of the present 7 invention are based are as follows:
8 A) Mass airflow (ACFM) is directly proportional to fan RPM;
9 B) Fan Static Pressure is directly proportional to the square of the fan RPM;
and 11 C) Fan Horsepower is directly proportional to the cube of the fan RPM.
12 The system of the present invention determines mass airflow by way of the 13 operation of the high torque, low variable speed, load bearing motor.
The variable 14 process control system of the present invention includes a plurality of pressure devices that are located in the cooling tower plenum. The data signals provided by these 16 pressure devices, along with the fan speed data from the VFD, fan pitch and the fan 17 map, are processed by an industrial computer and used to determine the mass airflow 18 in the fan cell.
19 The variable process control system of the present invention monitors cooling tower performance in real time and compares the performance data to design data in 21 order to formulate a performance trend over time. The variable process control system 22 of the present invention utilizes "trending" in order to revise, adjust and optimize the fan 23 variable speed schedule, and plan and implement cooling tower service, maintenance 24 and improvements as a function of process loading, such as hot day or cold day 1 limitations, or selection of the appropriate fill to compensate for poor water quality. The 2 variable process control system of the present invention utilizes long term trending to 3 achieve true performance prediction as opposed to periodic testing which is done in 4 prior art systems.
The present invention is a unique, novel and reliable approach to determining 6 cooling tower performance. The present invention uses fan horsepower and motor 7 current draw (i.e. amperes) in conjunction with a measured plenum pressure. The 8 measured plenum pressure equates to fan inlet pressure. The present invention uses 9 key parameters measured by the system including measured plenum pressure in combination with the fan speed, known from the VFD (Variable Frequency Drive), and ii the design fan map to determine mass airflow and real time cooling performance. The 12 plenum pressure is measured by at least one pressure device that is located in the fan 13 deck. The variable process control system of the present invention recognizes poor 14 performance conditions and generates warnings or alerts that prompt end-users to perform inspections and identify the required corrective actions.
16 The design criteria of the variable process control system of the present invention 17 are based upon the thermal design of the tower, the process demand, environmental 18 conditions and energy optimization. On the other hand, the prior art variable speed fan 19 gearbox systems are applied without knowledge of the tower thermal capacity and are only controlled by the basin temperature set-point.
21 A very important feature of the high-torque, low variable speed, load bearing 22 electric motor of the present invention is that it may be used in new installations (e.g.
23 new tower constructions or new fan assembly) or it can be used as a "drop-in"

1 replacement. If the high-torque, low variable speed, load bearing electric motor is used 2 as a "drop-in" replacement, it will easily interface with all existing fans and fan hubs and 3 provide the required torque and speed to rotate all existing and possible fan 4 configurations within the existing "installed" weight and fan height requirements.
The variable process control system of the present invention is programmed to 6 operate based on the aforesaid criteria as opposed to prior art systems which are 7 typically reactive to the basin temperature. Airflow generated by the variable process 8 control system of the present invention is a function of fan blade pitch, fan efficiency and 9 fan speed and is optimized for thermal demand (100% cooling) and energy consumption. Thermal demand is a function of the process. The variable process I control system of the present invention anticipates cooling demand based upon 12 expected seasonal conditions, historical and environmental conditions, and is designed 13 for variable speed, autonomous operation with control and supervision.
14 Since the high-torque, low variable speed, load bearing electric motor that drives the fan delivers constant high torque throughout its variable speed range, the fan pitch 16 is optimized for expected hot-day conditions (max cooling) and maximum efficiency 17 based on the expected and historical weather patterns and process demand of the plant 18 location. With the aforementioned constant high-torque, increased airflow is achieved 19 with greater fan pitch at slower speeds thereby reducing acoustic signature or fan noise in sensitive areas.
21 The variable process control system of the present invention also provides 22 capability for additional airflow or cooling for extremely hot days and is adaptive to 23 changes in process demand. The variable process control system of the present 1 invention can also provide additional cooling to compensate for loss of a cooling cell in a 2 multi-cell tower. This mode of operation of the variable process control system is 3 referred herein to the "Compensation Mode". In the Compensation Mode, the fan speed 4 of the remaining cells is increased to produce the additional flow through the tower to compensate for the loss of cooling resulting from the lost cells. The variable process 6 control system of the present invention is programmed not to increase the fan speed 7 greater than the fan tip speed when compensating for the loss of cooling resulting from 8 the loss cell. The compensation mode feature is designed and programmed into the 9 variable process control system of the present invention based upon the expected loss of a cell and its location in the tower. The variable process control system of the 11 present invention varies the speed of the fans in the remaining cells in accordance with 12 the configuration, geometry and flow characteristic of the cooling tower and the effect 13 each cell has on the overall cooling of the cooling tower. This provides the required 14 cooling and manages the resultant energy consumption of the cooling tower. The variable process control system of the present invention manages the variable speed of 16 the motor in each cell thereby providing required cooling while optimizing energy 17 consumption based upon the unique configuration and geometry of each cooling tower.
18 Operational characteristics of the variable process control system of the present 19 invention include:
1) autonomous variable speed operation based on process demand, thermal 21 demand, cooling tower thermal design and environmental conditions;
22 2) adaptive cooling that provides (a) regulated thermal performance based upon an 23 independent parameter or signal such as lower basin temperature to improve 1 cracking of heavier crude during a refining process, (b) regulated temperature 2 control to accommodate steam turbine back-pressure in a power plant for 3 performance and safety and (c) regulated cooling to prevent condenser fouling;
4 3) fan idle in individual cells of a multi-cell tower based on thermal demand and unique cooling tower design (i.e. fan idle) if thermal demand needs have been 6 met;
7 4) real-time feedback;
8 5) operator override for stopping or starting the fan, and controlling basin 9 temperature set-point for part-load operation;
6) uses fan speed, motor current, motor horsepower and plenum pressure in 11 combination with environmental conditions such as wind speed and direction, 12 temperature and wet-bulb temperature to measure and monitor fan airflow and 13 record all operating data, process demand trend and environmental conditions to 14 provide historical analysis for performance, maintenance actions, process improvements and expansions;
16 7) vibration control which provides 100% monitoring, control and supervision of the 17 system vibration signature with improved signature fidelity that allows system 18 troubleshooting, proactive maintenance and safer operation (post processing);
19 8) vibration control that provides 100% monitoring, control and supervision for measuring and identifying system resonances in real time within the variable 21 speed range and then locking them out of the operating range;
22 9) vibration control that provides 100% monitoring, control and supervision for 23 providing post processing of vibration signatures using an industrial computer 1 and algorithms such as Fast Fourier Transforms (FFT) to analyze system health 2 and provide system alerts to end users such as fan imbalance as well control 3 signals to the DAQ (data acquisition) device in the case of operating issues such 4 as impending failure;

10) provides for safe Lock-Out, Tag-Out (LOTO) of the fan drive system by 6 controlling the deceleration of the fan and holding the fan at stop while all forms 7 of energy are removed from the cell including cooling water to the cell so as to 8 prevent an updraft that could cause the fan to windmill in reverse;
9 11) provides for a proactive maintenance program based on actual operating data, cooling performance, trending analysis and post processing of data using a Fast

11 Fourier Transform to identify issues such as fan imbalance, impending fan hub

12 failure, impending fan blade failure and provide service, maintenance and repair

13 and replacement before a failure leads to a catastrophic event and loss of life,

14 the cooling asset and production.
12) provides a predictive maintenance program based on actual operating data, 16 cooling performance, trending analysis and environmental condition trending in 17 order to provide planning for cooling tower maintenance on major cooling tower 18 subsystems such as fill replacement and identify cooling improvements for 19 budget creation and planning for upcoming outages;
13) monitoring capabilities that alert operators if the system is functioning properly 21 or requires maintenance or an inspection;
22 14) operator may manually override the variable control system to turn fan on or off;

1 15) provides an operator with the ability to adjust and fine tune cooling based on 2 process demand with maximum hot-day override;
3 16) monitors auxiliary systems, such as pumps, to prevent excessive amounts of 4 water from being pumped into the tower distribution system which could cause collapse of the cooling tower;
6 17) continuously measures current process demand and environmental stress;
7 18) varies the fan speed in gradual steps as the variable process control system 8 learns from past process cooling demand as a function season, time, date and 9 environmental conditions to predict future process demand, wherein the variation of fan speed in gradual steps minimizes energy draw and system wear;
ii 19) the high-torque, low variable speed, load bearing electric motor is not limited in 12 reverse operation thereby allowing the use of regenerative drive options to 13 provide power to the grid when fans are windmilling in reverse;
14 20) automatic deicing; and 21)the high-torque, low variable speed, load bearing electric motor has the same 16 characteristics in reverse operation as it does in forward operation.
17 In one aspect, the present invention is directed to a wet-cooling tower system 18 comprising a load bearing, direct drive fan system and an integrated variable process 19 control system. The wet-cooling tower system comprises a wet-cooling tower that comprises a tower structure that has fill material located within the tower structure, a fan 21 deck located above the fill material, and a collection basin located beneath the fill 22 material for collecting cooled liquid. A fan stack is positioned upon the fan deck and a 23 fan is located within the fan stack. The fan comprises a hub to which are connected a 1 plurality of fan blades. The load bearing, direct drive fan system comprises a high-2 torque, low variable speed, load bearing, electric motor that has a rotatable shaft 3 connected to the hub. In one embodiment, the high-torque, low variable speed, load 4 bearing, electric motor has a rotational speed between 0 RPM and about 250 RPM. In another embodiment, the high-torque, low variable speed, load bearing, electric motor is 6 configured to have rotational speeds that exceed 500 RPM. The high-torque, low 7 variable speed, load bearing, electric motor is sealed and comprises a rotor, a stator 8 and a casing. The rotor and stator are located within the casing. The variable process 9 control system comprises a variable frequency drive device that is in electrical signal communication with the high-torque, low variable speed, load bearing, electric motor to ii control the rotational speed of the motor. The variable frequency drive device 12 comprises a variable frequency controller that has an input for receiving AC power and 13 an output for providing electrical signals that control the operational speed of the motor, 14 and a signal interface in electronic data signal communication with the variable frequency controller to provide control signals to the variable frequency controller so as 16 to control the motor RPM and to provide output motor status signals that represent the 17 motor speed, motor current draw, motor voltage, motor torque and the total motor power 18 consumption. The variable process control system further comprises a data acquisition 19 device in electrical signal communication with the signal interface of the variable frequency drive device for providing control signals to the variable frequency drive 21 device and for receiving the motor status signals. The wet-cooling tower system further 22 comprises a pair of vibration sensors that are in electrical signal communication with the 23 data collection device. Each vibration sensor is located within the motor casing where it 1 is protected from the enviroment and positioned on a corresponding motor bearing 2 structure. As a result of the structure and design of the high torque, low variable speed, 3 load bearing electric motor and the direct connection of the motor shaft to the fan or fan 4 hub, the resultant bearing system is stout (stiff and damped) and therefore results in a very smooth system with low vibration. In an alternate embodiment, at least one 6 additional vibration sensor is attached to the exterior of the motor casing or housing.
7 In comparison to the prior art, the vibration signature of the high torque, low 8 variable speed, load bearing electric motor has a low amplitude with clear signature 9 fidelity which allows for proactive service and maintenance and an improvement in safety and production. Trending of past cooling tower operation and post processing, ii vibration signal analysis (FFT) determines whether other vibration signatures are 12 indicating such issues as a fan blade imbalance, fan blade pitch adjustment, lubrication 13 issues, bearing issues and impending fan hub, fan blade and motor bearing failure, 14 which are major safety issues. The location of the vibration sensors on the motor bearings also allows for programming of lower amplitude shut-off parameters.
16 As described in the foregoing description, the variable process control system of 17 the present invention comprises a plurality of vibration sensors that may include 18 accelerometers, velocity and displacement transducers or similar devices to monitor, 19 supervise and control vibration characteristics of the direct drive fan system and the direct drive pump system that pumps water to and from the cooling tower. These 21 vibration sensors detect various regions of the motor and fan frequency band that are to 22 be monitored and analyzed.

1 The present invention has significantly less "frequency noise" because the 2 present invention eliminates ladder frames, torque tubes, shafts, couplings, gearboxes 3 and gearmesh that are commonly used in prior art systems. In accordance with the 4 invention, vibration sensors are located at the bearings of the high-torque, low variable speed, load bearing motor. Each vibration sensor outputs signals representing 6 vibrations of the motor bearings. Thus, vibrations that are directly coupled to the fan or 7 fan system are read directly at the bearings as opposed to the prior art technique of 8 measuring the vibrations at the ladder frame. As a result of this important feature of the 9 invention, the present invention can identify, analyze and correct for changes in the performance of the fan, thereby providing a longer running system that is relatively ii safer.
12 The variable process control system of the present invention further comprises a 13 plurality of temperature sensors in electrical signal communication with the data 14 collection device. The present invention utilizes external temperature sensors that measure the temperature of the exterior of the motor casing or housing and internal 16 temperature sensors located within the casing or housing of the motor to measure the 17 temperature within the casing, the temparature of the stator and coil windings. At least 18 one temperature sensor is located in the basin to measure temperature of liquid (e.g.
19 water) within the basin. Temperature sensors also measure the environmental temperature (e.g. ambient temperature). Another temperature sensor measures the 21 temperature of the air in the fan stack before the fan. The variable process control 22 system of the present invention further includes at least one pressure sensor located in 23 the fan deck that measures the pressure in the fan plenum, which equates to the 1 pressure at the fan inlet. The variable process control system further comprises a 2 computer in data signal communication with the data collection device.
The computer 3 comprises a memory and a processor to process the signals outputted by the vibration 4 and temperature sensors and to also process the pump flow signals and the motor status signals. The computer outputs control signals to the data collection device for 6 routing to the variable frequency drive device in order to control the speed of the motor 7 in response to the processing of the sensor signals.
8 The variable process control system also includes a leak detector probe for 9 detecting leakage of gasses from heat exchanges and other equipment.
Some key features of the system of the present invention are:
ii 1) reverse, de-ice, flying-start and soft-stop modes of operation with infinite control of 12 fan speed in both reverse and forward directions;
13 2) variable process control, refining and power generation;
14 3) capability of part-load operation;
4) maintaining vacuum backpressure for a steam turbine and crude cracking;
16 5) prevents damage and fouling of heat exchangers, condensers and auxiliary 17 equipment;
18 6) line-replaceable units such as hazardous gas monitors, sensors, meter(s) or probes 19 are integrated into the motor casing (or housing) to detect and monitor fugitive gas emissions in the fan air-steam accordance with the U.S. EPA (Environmental Protection 21 Agency) regulations;
22 7) variable speed operation with low, variable speed capability;

1 8) cells in multi-cell tower can be operated independently to meet cooling and optimize 2 energy;
3 9) 100% monitoring, autonomous control and supervision of the system;
4 10) automated and autonomous operation;
11) relatively low vibrations and high vibration fidelity due to system architecture and 6 structure;
7 12) changes in vibration signals are detected and analyzed using trending data and 8 post processing;
9 13) vibration sensors are integrated into the motor and thus protected from the surrounding harsh, humid environment;
ii 14) uses a variable frequency drive (VFD) device that provides signals representing 12 motor torque and speed;
13 15) uses DAQ (data acquisition) device that collects signals outputted by the VFD and 14 other data signals;
16) uses a processor that processes signals collected by the DAQ device, generates 16 control signals, routes control signals back to VFD and implements algorithms (e.g.
17 FFT) to process vibration signals;
18 17) uses mechanical fan-lock that is applied directly to the shaft of the motor to prevent 19 rotation of the fan when power is removed for maintenance and hurricane service;
18) uses a Lock-Out-Tag-Out (LOTO) procedure wherein the fan is decelerated to 0.0 21 RPM under power and control of the motor and VFD and the motor holds the fan at 0.0 22 RPM while a mechanical lock device is applied to the motor shaft to prevent rotation of 1 the fan, and then all forms of energy are removed per OSHA Requirements for Service, 2 Maintenance and Hurricane Duty (e.g. hurricane, tornado, shut-down, etc.);
3 19) produces regenerative power when the fan is windmilling;
4 20) the motor and VFD provide infinite control of the fan acceleration and can hold the fan at 0.0 RPM, and also provide fan deceleration and fan rotational direction;
6 21) allows fan to windmill in reverse due to cooling water updraft;
7 22) the high-torque, low variable speed, load bearing electric motor can operate in all 8 systems, e.g. wet-cooling towers, ACHEs, HVAC systems, chillers, blowers, etc.;
9 24) the high-torque, low variable speed, load bearing electric motor directly drive the fan and pumps; and ii 25) the high-torque, low variable speed, load bearing electric motor can be connected 12 to a fan hub of a fan, or directly connected to a one-piece fan.

14 BRIEF DESCRIPTION OF THE DRAWINGS:
Although the scope of the present invention is much broader than any particular 16 embodiment, a detailed description of the preferred embodiments follows together with 17 illustrative figures, wherein like reference numerals refer to like components, and 18 wherein:
19 FIG. 1 is a side view, in elevation, of a wet-cooling tower that uses a prior art fan drive system;
21 FIG. 2 is a block diagram of a variable process control system in accordance with 22 one embodiment of the present invention, wherein the variable process control system 23 controls the operation of a cooling tower;

1 FIG. 3 is a diagram of the feedback loops of the system of FIG. 2;
2 FIG. 4 is a block diagram illustrating the interconnection of a permanent magnet 3 motor, data acquisition device and variable frequency drive device, all of which being 4 shown in FIG. 2;
FIG. 5A is a diagram showing the internal configuration of the permanent magnet 6 motor shown in FIG. 4, the diagram specifically showing the location of the bearings of 7 the permanent magnet motor;
8 FIG. 5B is a diagram showing a portion of the permanent magnet motor of FIG.
9 5A, the diagram showing the location of the accelerometers within the motor housing;
FIG. 6 is a plot of motor speed versus horsepower for the high torque, low ii variable speed, load bearing permanent magnet motor used in direct drive fan system of 12 the present invention;
13 FIG. 7 is a graph illustrating a comparison in performance between the load 14 bearing, direct drive fan system of the present invention and a prior art gearbox-type fan drive system that uses a variable speed induction motor;
16 FIG. 8 is a side view, in elevation and partially in cross-section, of a wet-cooling 17 tower employing the load bearing, direct drive fan system of the present invention;
18 FIG. 9 is a graph showing a fan speed curve that is similar to a sine wave and 19 represents the increase and decrease in the fan speed over a twenty-four hour period in accordance with the present invention, the bottom portion of the graph showing a fan 21 speed curve representing changes in fan speed for a prior art variable speed fan drive 22 system;

1 FIG. 10 is a side view, in elevation and partially in cross-section, of an ACHE that 2 utilizes the load bearing, direct drive fan system of the present invention;
3 FIG. 11A is a vibration bearing report, in graph form, resulting from a test of the 4 load bearing permanent magnet motor and vibration sensing and analysis components of the present invention;
6 FIG. 11B is the same vibration bearing report of FIG. 11A, the vibration bearing 7 report showing a trip setting of 0.024G of a prior art gearbox;
8 FIG. 11C is a vibration severity graph showing the level of vibrations generated 9 by the load bearing permanent magnet motor of the present invention;
FIG. 12A is a side view, partially in cross-section, of the load bearing, direct drive ii fan system of the present invention installed in a cooling tower;
12 FIG. 12B is a bottom view of the load bearing permanent magnet motor depicted 13 in FIG. 12A, the view showing the mounting holes in the load bearing permanent 14 magnet motor;
FIG. 13 shows an enlargement of a portion of the view shown in FIG. 12A;
16 FIG. 14 is a side view, in elevation, showing the interconnection of the load 17 bearing permanent magnet motor shown in FIGS. 12A and 13 with a fan hub;
18 FIG. 15A is a diagram of a multi-cell cooling system that utilizes the load bearing, 19 direct drive fan system of the present invention;
FIG. 15B is a top view of a multi-cell cooling system;
21 FIG. 15C is a block diagram of a motor-control center (MCC) that is shown in 22 FIG. 15A;

1 FIG. 16A is a flowchart of a lock-out-tag-out (LOTO) procedure used to stop the 2 fan in order to conduct maintenance procedures;
3 FIG. 16B is a flow chart a Flying-Start mode of operation that can be 4 implemented by the load bearing permanent magnet motor and variable process control system of the present invention;
6 FIG. 16C is a graph of speed versus time for the Flying-Start mode of operation;
7 FIG. 17 is a graph of an example of condenser performance as a function of 8 water flow rate (i.e. variable speed pumps and constant basin temperature);
9 FIG. 18 is a partial view of the load bearing permanent magnet motor shown in FIGS. 4 and 5A, the load bearing permanent magnet motor having mounted thereto a 11 line-replaceable vibration sensor unit in accordance with another embodiment of the 12 invention;
13 FIG. 19 is a partial view of the load bearing permanent magnet motor shown in 14 FIGS. 4 and 5A, the load bearing permanent magnet motor having mounted thereto a line replaceable vibration sensor unit in accordance with a further embodiment of the 16 invention;
17 FIG. 20 is partial view of the load bearing permanent magnet motor shown in 18 FIGS. 4 and 5A having mounted thereto a line replaceable vibration sensor unit in 19 accordance with a further embodiment of the invention;
FIG. 21A is a top, diagrammatical view showing a fan-lock mechanism in 21 accordance with one embodiment of the invention, the fan lock mechanism being used 22 on the rotatable shaft of the motor shown in FIGS. 4 and 5A, the view showing the fan 1 lock mechanism engaged with the rotatable motor shaft in order to prevent rotation 2 thereof;
3 FIG. 21B is a top, diagrammatical view showing the fan lock mechanism of FIG.
4 21A, the view showing the fan lock mechanism disengaged from the rotatable motor shaft in order to allow rotation thereof;
6 FIG. 21C is a side elevational view of the motor shown in FIGS. 4 and 5A, the 7 view showing the interior of the motor and the fan-lock mechanism of FIGS. 21A and 8 21B mounted on the motor about the upper portion of the motor shaft, the view also 9 showing an additional fan-lock mechanism of FIGS. 21A and 21B mounted to the motor about the lower portion of the motor shaft;
11 FIG. 22 is a side elevational view of the upper portion of the permanent magnet 12 motor of FIGS. 4 and 5A, the permanent magnet motor having mounted thereto a 13 caliper-type lock mechanism for engaging the upper portion of the shaft of the motor;
14 FIG. 23 is a side elevational view of the lower portion of the permanent magnet motor of FIGS. 4 and 5A, the permanent magnet motor having mounted thereto a 16 caliper-type lock mechanism for engaging the lower portion of the shaft of the motor;
17 FIG. 24 is a side elevational view of the lower portion of the permanent magnet 18 motor of FIGS. 4 and 5A, the permanent magnet motor having mounted thereto a band-19 lock mechanism for engaging the lower portion of the shaft of the motor;
FIG. 25 is a side elevational view of the upper portion of the permanent magnet 21 motor of FIGS. 4 and 5A, the permanent magnet motor having mounted thereto a band-22 lock mechanism for engaging the upper portion of the shaft of the motor;

1 FIG. 26 is a block diagram of the load bearing, direct drive fan system and 2 variable process control system of the present invention used with a wet-cooling tower 3 that is part of an industrial process;
4 FIG. 27 is a side view, in cross-section and in elevation, of a wet cooling tower that utilizes the load bearing, direct drive fan system and variable process control 6 system of the present invention, the load bearing, direct drive motor being oriented such 7 that the motor shaft extends downward;
8 FIG. 28 is a diagram of one type of hybrid cooling tower that utilizes the load 9 bearing, direct drive fan system and variable process control system of the present invention;
11 FIG. 29 is a diagram of a commercial HVAC system that comprises a direct-drive 12 air-handling system in accordance with one embodiment of the present invention;
13 FIG. 30A is a diagram of a commercial HVAC system in accordance with another 14 embodiment of the present invention;
FIG. 30B is a plan view of a wide chord fan utilized in the HVAC system of FIG.
16 30A;
17 FIG. 31A is a side view of a centrifugal blower in accordance with one 18 embodiment of the present invention;
19 FIG. 31B is a view, partially in cross-section, of the interior of the centrifugal blower of FIG. 31A;
21 FIG. 32 is a side view of a centrifugal blower in accordance with another 22 embodiment of the present invention, the view showing a motor and interior of the 23 centrifugal blower;

1 FIG. 33 is a diagram of a commercial HVAC system in accordance with another 2 embodiment of the present invention;
3 FIG. 34 is a block diagram of a direct-drive air-handling system in accordance 4 with another embodiment of the present invention;
FIG. 35A is a diagram of a commercial HVAC system in accordance with another 6 embodiment of the present invention;
7 FIG. 35B is a plan view of the fan utilized in the HVAC system of FIG.
35A; and 8 FIG. 36 is a diagram of a commercial HVAC system in accordance with another 9 embodiment of the present invention.
11 BEST MODE FOR CARRYING OUT THE INVENTION:
12 As used herein, the terms "cooling apparatus" or "cooling system" shall mean 13 wet-cooling towers, forced draft air-cooled heat exchangers, induced draft air-cooled 14 heat exchangers, mechanical cooling towers, hybrid cooling towers, hybrid heat exchangers and chillers. Examples of wet-cooling towers are disclosed in U.S.
Patent 16 Nos. 8,111,028, entitled "Integrated Fan Drive System For Cooling Tower"
and U.S.
17 Patent No. 4,955,585, entitled Hydraulically Driven Fan System For Water Cooling 18 Tower". The entire disclosure of U.S. Patent Nos. 8,111,028 is hereby incorporated by 19 reference. Examples of forced-draft and induced draft air-cooled heat exchangers are disclosed in U.S. Patent No. 8,188,698, entitled "Integrated Fan Drive System For Air-21 Cooled Heat Exchanger (ACHE)". The entire disclosure of U.S. Patent No.
8,188,698 is 22 hereby incorporated by reference. An example of a hybrid heat exchanger apparatus is 23 disclosed in US Patent Application Publication No. U520120067546, entitled "Hybrid 1 Heat Exchanger Apparatus And Method Of Operating The Same". An example of a 2 hybrid cooling tower is disclosed in European Patent Application Publication No.
3 EP0968397, entitled "Hybrid Cooling Tower".
4 As used herein, the term "fan loads" shall include fan dead weight, fan forward thrust, fan reverse thrust, yaw loads, torque reaction loads, fan forces and moments.
6 As used herein, the term "motor" shall mean any electric motor with a rotor and 7 stator that creates flux.
8 As used herein, the terms "motor casing" or "motor housing" are used 9 interchangeably and shall have the same meaning and include motor casings or housings of stacked lamination frame configuration.
ii As used herein, the term "load bearing, direct drive system" shall mean a drive 12 system that comprises a load bearing, direct drive motor that has its shaft directly 13 coupled to a cooling tower fan wherein the load bearing, direct drive motor provides the 14 required torque and speed range for rotating the fan while simultaneously supporting the fan loads and maintaining the required gap between the rotor and stator in order to 16 create flux.
17 As used herein, the terms "process", "plant process" or "industrial process" shall 18 mean an industrial process such as a petroleum refinery, power plant, turbine, crude 19 cracker, fertilizer plant, glass manufacturing plant, chemical plant, etc.
As used herein, the terms "process liquid" means the liquids, such as water or 21 other coolant, that are used for cooling purposes in the process.
22 As used herein, the terms "process demand" or "process cooling demand"
mean 23 the amount of cooling liquids used by the process.

1 As used herein, the term "part-plant load" means process demand that is less 2 than maximum process demand.
3 As used herein, the terms "basin temperature" or "collection basin temperature"
4 mean the temperature of the water or other liquid that is in the collection basin of a wet-s cooling tower;
6 As used herein, the term "Environmental Stress" shall mean, collectively, ambient 7 temperature, relative humidity, dry-bulb temperature, wet-bulb temperature, wind speed, 8 wind direction, solar gain and barometric pressure.
9 As used herein, the term "Cooling Tower Thermal Capacity" is the heat-rejection capability of the cooling tower. It is the amount of cold water that can be returned to the 11 process for given temperature and flow rate at maximum hot-day and wet-bulb 12 conditions. Cooling Tower Thermal Capacity will be reduced as the cooling tower 13 components degrade, such as the fill material becoming clogged due to poor water 14 quality. For a given AT (difference between temperatures of hot and cold water) and the flow rate, the cooling tower fans will have to operate at higher speed and for longer 16 amounts of time given the environmental stress in a degraded tower (that is being 17 monitored and trended).
18 As used herein, the term "process thermal demand" or "thermal demand"
means 19 the heat that has to be removed from the process liquid (e.g. water) by the cooling tower. In its simplest terms, thermal demand of the process is expressed as the water 21 temperature from the process (hot water) and water temperature returned to the 22 process (cold water) for a give flow rate;
23 As used herein, the terms "fan map" and "fan performance curve"
represent the 1 data provided for fan blades with a given solidity. Specifically, the data represents the 2 airflow of air moved by a specific fan diameter, model and solidity for a given fan speed 3 and pitch at a given temperature and wet-bulb (air density).
4 As used herein, the terms "trending" or "trend" means the collection of cooling tower parameters, events and calculated values with respect to time that define 6 operating characteristics such as cooling performance as a function of environmental 7 stress and Process Thermal Demand.
8 Referring to FIGS. 2 and 4, there is shown the variable process control system of 9 the present invention for managing the operation of fans and pumps in cooling apparatus 10. As stated in the foregoing description, cooling apparatus 10 may be any 11 one of a variety of cooling apparatuses or cooling systems including a wet-cooling 12 tower, hybrid cooling tower, mechanical tower, forced draft air-cooled heat exchanger, 13 induced draft air-cooled heat exchanger (ACHE), hybrid heat exchanger, chiller and 14 HVAC system. All of these cooling apparatuses and cooling systems are commonly used to cool liquids used in a process such as an industrial process. Examples of 16 applicable industrial processes include petroleum refineries, chemical plants, etc. For 17 purposes of describing the aspects and embodiments of the present invention, cooling 18 apparatus 10 is described herein as a wet-cooling tower. Cooling apparatus 10 19 comprises fan 12 and fan stack 14. As is known in the field, cooling towers may utilize fill material which is described in the aforementioned U.S. Patent No.
8,111,028. Fan 21 12 comprises hub 16 and a plurality of fan blades 18 that are connected to and extend 22 from hub 16. The system of the present invention comprises a high-torque, variable 23 speed, load bearing electric motor 20. For purposes of describing the invention, the 1 ensuing description is in terms of motor 20 being a load bearing permanent magnet 2 motor. However, it is to be understood that motor 20 can be configured as any other 3 high-torque, variable speed, load bearing electric motor, some of which are described in 4 the ensuing description. Motor 20 comprises motor housing or casing 21A
(see FIG. 4).
Casing comprises top cover 21A and bottom cover 21B. Motor 20 further comprises 6 rotatable shaft 24. In this embodiment, motor shaft 24 is directly connected to fan hub 7 16. The connection of motor shaft 24 to fan hub 16 is described in detail in the ensuing 8 description. It is to be that motor 20 can interfaces with all fans having diameters 9 between about one foot and forty feet. Motor shaft 24 can be directly connected to the fan, or directly connected to the fan hub, or connected to the fan with a shaft adapter, or 11 connected to the fan hub with a shaft adapter, or connected to the fan with a shaft 12 extension.
13 Referring to FIG. 2, power cable 105 has one end that is terminated at motor 20.
14 Specifically, power cable 105 is factory sealed to Class One, Division Two, Groups B, C
and D specifications and extends through the motor housing 21 and is terminated within 16 the interior of motor housing 21 during the assembly of motor 20.
Therefore, when 17 installing motor 20 in a cooling apparatus, it is not necessary for technicians or other 18 personnel to electrically connect power cable 105 to motor 20. The other end of power 19 cable 105 is electrically connected to motor disconnect junction box 106. Power cable 105 is configured as an area classified, VFD rated and shielded power cable.
Motor 21 disconnect junction box 106 includes a manual emergency shut-off switch.
Motor 22 disconnect junction box 106 is primarily for electrical isolation. Power cable 105 23 comprises three wires that are electrically connected to the shut-off switch in motor-1 disconnect junction box 106. Power cable 107 is connected between the shut-off switch 2 in motor-disconnect junction box 106 and VFD device 22. Power cable 107 is 3 configured as an area classified, VFD rated and shielded power cable. The electrical 4 power signals generated by VFD device 22 are carried by power cable 107 which delivers these electrical power signals to junction box 106. Motor power cable 105 is 6 connected to power cable 107 at junction box 106. Thus, motor power cable 105 then 7 provides the electrical power signals to motor 20.
8 Referring to FIGS. 2 and 4, quick-disconnect adapter 108 is connected to motor 9 housing 21. In one embodiment, quick-disconnect adapter 108 is a Turck Multifast Right Angle Stainless Connector with Lokfast Guard, manufactured by Turck Inc.
of 11 Minneapolis, MN. The sensors internal to motor housing 21 are wired to quick-12 disconnect adapter 108. Cable 110 is connected to quick-disconnect adapter 108 and 13 to communication data junction box 111. Communication data junction box 111 is 14 located on the fan deck. The electronic components in communication data junction box 111are powered by a voltage source (not shown). Cable 110 is configured as an 16 area-classified multiple connector shielded flexible control cable.
Cable 112 is 17 electrically connected between communication data junction box 111 and data 18 acquisition device 200 (referred to herein as "DAQ device 200"). In one embodiment, 19 cable 112 is configured as an Ethernet cable. As described in the foregoing description, VFD device 22 is in data communication with Data Acquisition Device (DAQ) device 21 200. VFD device 22 and DAQ device 200 are mounted within Motor Center Enclosure 22 26 (see FIGS. 2 and 4). A Motor Control Enclosure typically is used for a single motor 23 or fan cell. The MCE 26 is typically located on the fan deck in close proximity to the 1 motor. The MCE 26 houses VFD device 22, DAQ device 200, industrial computer 300 2 and the power electronics. In one embodiment, MCE 26 is a NEMA 4X Rated Cabinet.
3 VFD device 22 and DAQ device 200 are discussed in detail in the ensuing description.
4 Referring to FIGS. 4 and 5A, the load bearing, direct drive fan system of the present invention comprises high torque, low variable speed, load bearing motor 20.
6 The casing, bearings and shaft design of motor 20 ensures structural and dynamic 7 integrity and also provides for venting and cooling of motor 20 without the use of a 8 shroud or similar device typically used in prior art fan drive systems.
Motor 20 9 comprises a bearing system and structure that supports the fan loads of large diameter fans, e.g. rotational loads, axial thrust loads, axial reverse thrust loads, fan dead weight, ii radial loads, moment loads, and yaw loads. Thus, motor 20 can bear the loads of a 12 cooling tower fan whether the fan is rotating or at 0.0 RPM. Motor 20 can be mounted 13 in any position such that output shaft 24 can be oriented in any position, e.g. upward, 14 downward, horizontal, angulated, etc. This can be achieved because motor 20 is a sealed motor and eliminates the oil bath system which is used in prior art systems. In 16 this embodiment, motor 20 is a permanent magnet motor. Shaft 24 of motor 20 is 17 directly connected to the fan hub 16. Thus, motor 20 directly drives fan 12 without the 18 loss characteristics and mechanical problems typical of prior art gearbox drive systems.
19 Motor 20 has a relatively high flux density and is controlled only by electrical signals provided by VFD device 22. Thus, there are no drive shaft, couplings, gear boxes or 21 related components which are found in the prior art gearbox-type fan drive systems.
22 Motor 20 comprises stator 32, rotor 34 and spherical roller thrust bearing 40 that is 23 located at the lower end of motor shaft 24. Referring to FIG. 5A, in accordance with one 1 embodiment of the invention, the clearance between stator 32 and rotor 34 is 0.060 inch 2 and is designated by the letter "X" in FIG. 5A. Spherical roller thrust bearing 40 absorbs 3 the thrust load caused by the weight of fan 12 and fan thrust forces due to airflow.
4 Motor 20 further comprises cylindrical roller bearing 42 that is located immediately above spherical roller thrust bearing 40. Cylindrical roller bearing 42 opposes radial 6 loads at the thrust end of shaft 24. Radial loads are caused by fan assembly unbalance 7 and yaw moments due to unsteady wind loads. Motor 20 further comprises tapered 8 roller output bearing 44. Tapered roller output bearing 44 is configured to have a high 9 radial load capability coupled with thrust capability to oppose the relatively low reverse thrust loads that occur during de-icing (reverse rotation) or high wind gust.
Although ii three bearings are described, motor 20 is actually a two-bearing system.
The two 12 bearings" are cylindrical roller bearing 42 and tapered roller output bearing 44 because 13 these two bearings are radial bearings that locate and support the shaft relative to motor 14 casing housing 21 and the mounting structure. Spherical roller thrust bearing 40 is a thrust bearing that is specifically designed so that it does not provide any radial locating 16 forces but only axial location. In this embodiment, the particular design, structure and 17 location of the bearings and the particular design and structure of the motor casing 21, 18 rotor 34 and shaft 24 cooperate to maintain the clearance "X" of 0.060 inch between 19 stator 32 and rotor 34. It is necessary to maintain this clearance "X"
of 0.060 inch in order to produce the required electrical flux density and obtain optimal motor operation.
21 Thus, in accordance with the invention, the bearings of the motor bear the loads of a 22 rotating fan while simultaneously maintaining the clearance "X" of 0.060 inch between 23 stator 32 and rotor 34. This feature is unique to motor design and is referred to herein 1 as a "load bearing motor". It is to be understood that, depending upon the application, 2 the sizes and dimensions of the motor casing, stator, rotor, shaft and bearing system 3 may vary such that the clearance "X" is different than 0.060 inch. The design of 4 permanent magnet motor 20 has a reduced Life-Cycle Cost (LCC) as compared to the prior art gearbox fan drive systems described in the foregoing description.
Bearing 6 housing 50 houses bearing 44. Bearing housing 52 houses bearings 40 and 42.
7 Bearing housings 50 and 52 are isolated from the interior of motor housing 21 by nitrile 8 rubber, double lip-style radial seals. The combination of the low surface speed of motor 9 shaft 24 and synthetic lubricants result in accurate predicted seal reliability and operational life. The permanent magnet motor 20 includes seal housing 53 that 11 comprises a Grounded lnpro TM Seal bearing isolator. This Grounded lnpro 12 Seal TM bearing isolator electrically grounds the bearings from the VFD.
The motor shaft 13 seal comprises an lnpro TM seal bearing isolator in tandem with a double radial lip seal.
14 The lnpro TM seal bearing isolator is mounted immediately outboard of the double radial lip seal. The function of the lnpro TM seal is to seal the area where shaft 24 penetrates 16 top cover 21A of motor housing 21. The lnpro seal also incorporates a fiber grounding 17 brush to prevent impressed currents in shaft 24 that could damage the bearings. The 18 double radial lip seal excludes moisture and solid contaminants from the seal lip 19 contact. Motor housing 21 includes bottom cover 21B. Motor 20 is a sealed system unlike typical prior art gearbox systems which have an open lubrication design. Such 21 prior art gearbox systems are not suited for cooling tower service since the open 22 lubrication system becomes contaminated from the chemicals, humidity and biological 23 contamination in the cooling tower. The design and structure of motor 20 eliminates 1 these problems of prior art gearbox systems. Since motor 20 is sealed, motor 20 may 2 be operated in wet or dry environments and in any orientation, e.g. motor shaft in 3 upward vertical orientation, motor shaft in downward vertical orientation or motor shaft 4 oriented at an angle. In one embodiment, permanent magnet motor 20 has the following operational and performance characteristics:
6 Speed Range: 0-250 RPM
7 Maximum Power: 133 hp/100 KW
8 Number of Poles: 16 9 Motor Service Factor: 1:1 Rated Current: 62 A (rms) 11 Peak Current: 95 A
12 Rated Voltage: 600 V
13 Drive Inputs: 460 V, 3 phase, 60 Hz, 95A (rms max. continuous) 14 Area Classification: Class 1, Division 2, Groups B, C, D
Insulation Class H
16 Permanent magnet motor 20 can be configured to have different operational 17 characteristics. For example, permanent magnet motor 20 can be configured to have a 18 maximum rotational speed less than or equal to 900 RPM. However, it is to be 19 understood that in all embodiments, motor 20 is designed to the requirements of Class 1, Div. 2, Groups B, C and D. FIG. 6 shows a plot of speed vs. horsepower for motor 21 20. However, it is to be understood that the aforesaid operational and performance 22 characteristics just pertain to one embodiment of permanent magnet motor 20 and that 23 motor 20 may be modified to provide other operational and performance characteristics 1 that are suited to a particular application. Referring to FIG. 7, there is shown a graph 2 that shows "Efficiency A" versus "Motor Speed (RPM)" for motor 20 and a prior art fan 3 drive system using a prior art, variable speed, induction motor. Curve 100 pertains to 4 motor 20 and curve 102 pertains to the prior art fan drive system. As can be seen in the graph, the efficiency of motor 20 is relatively higher than the prior art fan drive system 6 for motor speeds between about 60 RPM and about 200 RPM. The characteristics of 7 permanent magnet motor 20 of the present invention provide the flexibility of optimizing 8 fan pitch for a given process demand.
9 Motor 20 has relatively low maintenance with a five year lube interval.
The design and architecture of motor 20 substantially reduces the man-hours associated ii with service and maintenance that would normally be required with a prior art, induction 12 motor fan drive system. The bearing L10 life is calculated to be 875,000 hours. In 13 some instances, motor 20 can eliminate up to 1000 man-hours of annual service and 14 maintenance in a cooling tower.
In an alternate embodiment, motor 20 is configured with auto-lube grease options 16 as well as grease fittings depending on the user. Motor 20 eliminates shaft, coupling 17 and related drive-train vibrations, torsional resonance and other limitations typically 18 found in prior art drive systems and also eliminates the need for sprag-type clutches 19 typically used to prevent opposite rotation of the fans. Motor 20 eliminates widely varying fan-motor power consumption problems associated with prior art gearboxes due 21 to frictional losses caused by mechanical condition, wear and tear, and impact of 22 weather on oil viscosity and other mechanical components. The high, constant torque 23 of motor 20 produces the required fan torque to accelerate the fan through the speed 1 range.
2 Referring to FIGS. 2, 4 and 5A, shaft 24 of permanent magnet motor 20 rotates 3 when the appropriate electrical signals are applied to permanent magnet motor 20.
4 Rotation of shaft 24 causes rotation of fan 12. VFD device 22 comprises a plurality of independently controlled programmable variable frequency drive (VFD) devices 23A, 6 23B, 23C, 23D and 23E (see FIG. 26). VFD device 23A controls motor 20.
The 7 remaining VFD devices control the permanent magnet motors in the variable speed 8 pumps (see FIG. 26). DAQ device 200 provides control signals to each of the VFD
9 devices 23A, 23B, 23C, 23D and 23E. These features are discussed later in the ensuing description. VFD device 23A provides the appropriate electrical power signals ii to motor 20 via cables 107 and 105. There is two-way data communication between 12 VFD device 22 and DAQ device 200. DAQ device 200 comprises a controller module 13 which comprises a computer and/or microprocessor having computer processing 14 capabilities, electronic circuitry to receive and issue electronic signals and a built-in keyboard or keypad to allow an operator to input commands. In one embodiment, DAQ
16 device 200 comprises a commercially available CSE Semaphore TBox RTU
System 17 that comprises a data acquisition system, computer processors, communication 18 modules, power supplies and remote wireless modules. The CSE Semaphore TBox 19 RTU System is manufactured by CSE Semaphore, Inc. of Lake Mary, FL. In a preferred embodiment, the CSE Semaphore TBox RTU System is programmed with a 21 commercially available computer software packages known as Dream ReportTM and 22 TViewTm which analyze collected data. In an alternate embodiment, the CSE
23 Semaphore TBox RTU System is programmed with commercially available software 1 known as TwinSoftTm. In DAQ device 200 is described in detail in the ensuing 2 description. VFD device 22 comprises a variable frequency controller 120 and signal 3 interface 122. VFD device 22 controls the speed and direction (i.e.
clockwise or 4 counterclockwise) of permanent magnet motor 20. AC voltage signals are inputted into variable frequency controller 120 via input 124. Variable frequency controller 6 outputs the power signals that are inputted into motor 20 via power cables 107 and 105.
7 Referring to FIG. 4, signal interface 122 is in electrical signal communication with DAQ
8 device 200 via data signal bus 202 and receives signals to start, reverse, accelerate, 9 decelerate, coast, stop and hold motor 20 or to increase or decrease the RPM of motor 20. In a preferred embodiment, signal interface 122 includes a microprocessor.
Signal ii interface 122 outputs motor status signals over data bus 202 for input into DAQ device 12 200. These motor status signals represent the motor speed (RPM), motor current 13 (ampere) draw, motor voltage, motor power dissipation, motor power factor, and motor 14 torque.
VFD device 23A measures motor current, motor voltage and the motor power 16 factor which are used to calculate energy consumption. VFD device 23A
also measures 17 motor speed, motor power and motor torque. VFD device 23A also measures Run 18 Time/Hour Meter in order to provide a time stamp and time-duration value. The time 19 stamp and time-duration are used by industrial computer 300 for failure and life analysis, FFT processing, trending, and predicting service maintenance.
Industrial 21 computer 300 is discussed in detail in the ensuing description.
22 Referring to FIGS. 4 and 26, VFD devices 23B, 23C, 23D and 23E outputs 23 electrical power signals 1724, 1732, 1740 and 1754, respectively, for controlling the 1 variable speed pumps 1722, 1730, 1738 and 1752, respectively, that pump liquid (e.g.
2 water) to and from the cooling tower. This aspect of the present invention is discussed 3 in detail in the ensuing description.
4 In one embodiment, each of the VFD devices is configured as an ABB-VFD manufactured by ABB, Inc.
6 Referring to FIG. 8, there is shown a partial view of a cooling apparatus 10 that 7 utilizes the direct drive fan system of the present invention. In this embodiment, cooling 8 apparatus 10 comprises a wet-cooling tower and motor 20 is the load bearing 9 permanent magnet motor discussed in the foregoing description. The wet-cooling tower comprises fan 12, fan stack 14, fan hub 16, and fan blades 18, all of which were ii discussed in the foregoing description. Fan stack 14 is supported by fan deck 250. Fan 12 stack 14 can be configured to have a parabolic shape or a cylindrical (straight) shape as 13 is well known in the field. Motor 20 is supported by a metal frame or ladder frame or 14 torque tube that spans across a central opening (not shown) in fan deck 250. Motor shaft 24 is configured as a keyed shaft and is directly connected to fan hub 16 (see FIG.
16 14). Power cables 105 and 107, motor-disconnect junction box 106 and quick-17 disconnect connector 108 were previously discussed in the foregoing description.
18 Power cable 107 is connected between motor-disconnect junction box 106 and variable 19 frequency controller 120 of VFD device 22 (see FIGS. 2 and 4) which is located inside MCE 26. Referring to FIGS. 2, 4 and 8, cable 110 is electrically connected between 21 quick-disconnect adapter 108 and communication data junction box 111.
These signals 22 are fed to the DAQ device 200 located in MCE 26 via cable 112 as described in the 23 foregoing description. Industrial computer 300 is also located within MCE 26.

1 Referring to FIG. 10, there is shown an air-cooled heat exchanger (ACHE) that 2 utilizes the direct drive fan system of the present invention. This particular ACHE is an 3 induced-draft ACHE. The remaining portion of the ACHE is not shown since the 4 structure of an ACHE is known in the art. The ACHE comprises tube bundle 800, vertical support columns 801A and 801B, parabolic fan stack 802, horizontal support 6 structure 804, support members 805 and fan assembly 12. Fan assembly 12 comprises 7 fan hub 16 and fan blades 18 that are attached to fan hub 16. Vertical shaft 806 is 8 connected to fan hub 16 and coupled to motor shaft 24 with coupling 808.
Motor 20 is 9 connected to and supported by horizontal member 804. Additional structural supports 810A and 810B add further stability to motor 20. Coupling 808 drives a pair of separate ii bearing systems 850 and 852. The separate bearing systems 850 and 852 allow the 12 ACHE support structure to bear either full or partial fan loads.
13 As described in the foregoing description, one end of power cable 105 is 14 terminated at motor 20 and the other end of power cable 105 is electrically connected to the motor disconnect junction box 106. Power cable 107 is connected between motor 16 disconnect junction box 106 and VFD device 22. As described in the foregoing 17 description, cable 110 is electrically connected between quick-disconnect adapter 108 18 and communication data junction box 111, and cable 112 is electrically connected 19 between communication data junction box 111 and DAQ device 200. VFD
device 22 and DAQ device 200 are mounted within a Motor Control Enclosure (MCE) which is not 21 shown in FIG. 10 but which was described in the foregoing description.
22 Referring to FIG. 2, the system of the present invention further comprises 23 industrial computer 300. Industrial computer 300 is always co-located with DAQ device 1 200. Industrial computer 300 is in data communication with data bus 302.
Data bus 2 302 is in data communication with DAQ device 200. Industrial computer 300 is 3 responsible for post-processing of performance data of the cooling tower and the 4 system of the present invention. Included in this post-processing function are data logging and data reduction. Industrial computer 300 is programmed with software 6 programs, an FFT algorithm and other algorithms for processing system performance 7 data, environmental data and historical data to generate performance data reports, 8 trend data and generate historical reports based on performance data it receives from 9 DAQ device 200. Industrial computer 300 also stores data inputted by the operators through the plant DCS 315. Such stored data includes fan maps, fan pitch, Cooling ii Tower Design Curves, and Thermal Gradient analysis data. The wet-bulb temperature 12 data is continually calculated from relative humidity and ambient temperature and is 13 inputted into industrial computer 300. User input 304 (e.g. keyboard) 304 and display 14 306 (e.g. display screen) are in data signal communication with industrial computer 300.
An operator uses user input 304 to input commands into industrial computer 300 to 16 generate specific types of processed data. Industrial computer 300 displays on display 17 306 real-time data relating to the operation of the cooling tower and the system of the 18 present invention, including motor 20. Industrial computer 300 is also used to program 19 new or revised data into DAQ device 200 in response to changing conditions such as variable process demand, motor status, fan condition, including fan pitch and balance, 21 and sensor output signals. The sensor output signals are described in the ensuing 22 description. In a preferred embodiment, industrial computer 300 is in data signal 23 communication with host server 310. Host service 310 is in data signal communication 1 with one or more remote computers 312 that are located at remote locations in order to 2 provide off-site monitoring and analysis. Industrial computer 300 is also in data signal 3 communication with the plant Distributed Control System (DCS) 315, shown in phantom 4 in FIGS. 2 and 3. Users or operators can input data into DCS 315 including revised temperature set-points, or revised pump flow rates or even change the plant load setting 6 from full plant load to part-plant load. This revised information is communicated to 7 industrial computer 300 which then routes the information to DAQ device 200. DAQ
8 device 200 and industrial computer 300 provide real-time cooling performance 9 monitoring, real-time condition fault monitoring and autonomous control of fan speed.
In a preferred embodiment, industrial computer 300 receives continuous weather ii data from the national weather surface or NOAA. Industrial computer 300 can receive 12 this data directly via an Internet connection or it can receive the data via host server 13 310. Industrial computer 300 converts such weather data to a data form that can be 14 processed by DAQ device 200. In a preferred embodiment, as shown in FIG.
2, the variable process control system of the present invention further comprises on-site 16 weather station 316 which is in data signal communication with the Internet and DAQ
17 device 200. On-site weather station 316 comprises components and systems to 18 measure parameters such as wind speed and direction, relative humidity, ambient 19 temperature, barometric pressure and wet-bulb temperature. These measured parameters are used by industrial computer 300 to determine Cooling Tower Thermal 21 Capacity and also to determine the degree of icing on the tower. These measure 22 parameters are also used for analysis of the operation of the cooling tower. On-site 23 weather station 316 also monitor's weather forecasts and issues alerts such as high 1 winds, freezing rain, etc.
2 In one embodiment, the VFD device 22, DAQ device 200, industrial computer 3 300 and power electronics are located in MCE 26. The Distributed Control System 4 (DCS) 315 is integrated with industrial computer 300 at MCE 26. Operators would be able to log onto industrial computer 300 for trending information and alerts.
DAQ device 6 200 automatically generates and issues alerts via email messages or SMS
text 7 messages to multiple recipients, including the Distributed Control System (DCS), with 8 attached documents and reports with live and historical information as well as alarms 9 and events.
In one embodiment, industrial computer 300 is programmed to allow an operator ii to shut down or activate the direct drive fan system from a remote location.
12 Referring to FIGS. 2 and 4, VFD device 22 controls the speed, direction and 13 torque of fan 12. DAQ device 200 is in electrical signal communication with VFD device 14 22 and provides signals to the VFD device 22 which, in response, outputs electrical power signals to motor 20 in accordance with a desired speed, torque and direction.
16 Specifically, the DAQ device 200 generates control signals for VFD
device 22 that 17 define the desired fan speed (RPM), direction and torque of motor 20.
DAQ device 200 18 is also programmed to issue signals to the VFD device 22 to operate the fan 12 in a 19 normal mode of operation referred to herein as "energy optimization mode". This " energy optimization mode" is described in detail in the ensuing description.
When 21 acceleration of motor 20 is desired, DAC device 200 outputs signals to VFD device 22 22 that define a programmed rate of acceleration. Similarly, when deceleration of motor 20 23 is desired, DAQ device 200 outputs signals to VFD device 22 that define a programmed 1 rate of deceleration. If it is desired to quickly decrease the RPM of motor 20, DAQ
2 device 200 outputs signals to VFD device 22 that define a particular rate of deceleration 3 that continues until the motor comes to a complete stop (e.g. 0.0 RPM).
4 DAQ device 200 provides several functions in the system of the present invention. DAQ device 200 receives electronic data signals from all sensors and 6 variable speed pumps (discussed in the ensuing description). DAQ device 200 also 7 continuously monitors sensor signals sent to the aforesaid sensors to verify that these 8 sensors are working properly. DAQ device 200 is programmed to issue an alert is there 9 is a lost sensor signal or a bad sensor signal. DAQ device 200 automatically adjusts the RPM of motor 20 in response to the sensor output signals. Accordingly, the system ii of the present invention employs a feedback loop to continuously adjust the RPM of 12 motor 20, and hence fan 12, in response to changes in the performance of the fan, 13 cooling tower characteristics, process load, thermal load, pump flow-rate and weather 14 and environmental conditions. A diagram of the feedback loop is shown in FIG. 3. DAQ
device 200 is programmable and can be programmed with data defining or representing 16 the tower characteristics, trend data, the geographical location of the cooling tower, 17 weather and environmental conditions. DAQ device 200 is configured with internet 18 compatibility (TCP/IP compatibility) and automatically generates and issues email 19 messages or SMS text messages to multiple recipients, including the Distributed Control System (DCS), with attached documents and reports with live and historical 21 information as well as alarms and events. In a preferred embodiment, DAQ
device 200 22 comprises multiple physical interfaces including Ethernet, RS-232, RS-485, fiber optics, 23 Modbus, GSM/GPRS, PSTN modem, private line modem and radio. Preferably, DAQ

1 device 200 has SCADA compatibility. In one embodiment, DAQ device 200 is 2 configured as a commercially available data acquisition system. In an alternate 3 embodiment, DAQ device 200 is configured to transmit data to industrial computer 300 4 via telemetry signals.
Referring again to FIG. 3, the feedback loops enable continuous monitoring of 6 the operation of motor 20, fan 12 and the variable speed pumps and also effect 7 automatic adjustment of the RPM of motor 20 and of the permanent magnet motors in 8 the variable speed pumps (see FIG. 26). The feedback loops shown in FIG.
3 allows 9 motor 20 to be operated in any one of a plurality of modes of operation which are discussed in the ensuing description.
11 Flying Start Mode 12 The variable process control system of the present invention is configured to 13 operate in a "Flying Start Mode" of operation with infinite control of fan 12. A flow chart 14 of this mode of operation is shown in FIGS. 16B. In this mode of operation, VFD device 22 senses the direction of the fan 12 (i.e. clockwise or counter-clockwise) and then: (a) 16 applies the appropriate signal to motor 20 in order to slow fan 12 to a stop (if rotating in 17 reverse), or (b) ramps motor 20 to speed, or (c) catches fan 12 operating in the correct 18 direction and ramps to speed. The graph in FIG. 16C illustrates the "Flying Start Mode".
19 The nomenclature in FIG. 16C is defined as follows:
"A" is a desired, fixed or constant speed for motor 20 (i.e. constant RPM);
21 "B" is the Time in seconds for VFD device 22 to bring motor 20 from 0.0 RPM to 22 desired RPM (i.e. Ramp-Up Time).
23 "C" is the Time in seconds for VFD device 22 to bring motor 20 from desired 1 RPM to 0.0 RPM (i.e. Ramp-Down Time).
2 Angle D" is the acceleration time in RPM/second and is defined as "cos(A/B)";
3 Angle E" is the deceleration time in RPM/second and is defined as "cos(A/C)";
4 Angle D and Angle E may be identical, but they do not have to be.
The "Flying Start" mode may be implemented if any of the following conditions 6 exist:
7 Condition #2: Motor 20 is detected at 0.0 RPM. The VFD device 22 accelerates 8 motor 20 to desired RPM in "B" seconds.
9 Condition #1: Motor 20 is detected running in reverse direction. The VFD
device 22 calculates time to bring motor 20 to 0.0 RPM at rate of D. Motor 20 is then 11 accelerated to "A" RPM. Total time for motor to reach "A" RPM is greater than "B"
12 seconds.
13 Condition #3: Motor 20 is detected running in forward direction. VFD
device 22 14 calculates position of motor 20 on ramp and uses rate "D" to accelerate motor to "A"
RPM. Total time for motor 20 to reach "A" RPM is less than "B" seconds.
16 Condition #4 ¨ Motor is detected running greater than "A" RPM. VFD
device 22 17 calculates time to decelerate motor to "A" RPM using rate E.
18 This Flying Start mode of operation is possible because the novel bearing design 19 of motor 20 allows the fan to windmill in reverse.
21 Soft Start Mode 22 The variable process control system of the present invention is configured to 23 operate in a "Soft Start Mode" of operation. In this mode of operation, with VFD device 1 22 is programmed to initiate acceleration in accordance with predetermined ramp rate.
2 Such a controlled rate of acceleration eliminates breakage of system components with 3 " across the line starts". Such "breakage" is common with prior art gearbox fan drive 4 systems.

7 Hot Day Mode 8 Another mode of operation that can be implemented by the variable process 9 control system of the present invention is the "hot day" mode of operation. The "hot day" mode of operation is used when more cooling is required and the speed of all fans 11 is increased to 100% maximum fan tip speed. The "hot day" mode of operation can 12 also be used in the event of an emergency in order to stabilize an industrial process that 13 may require more cooling.
14 Energy Optimization Mode The variable process control system of the present invention is configured to 16 operate in an "Energy Optimization Mode". In this mode of operation, the fan 12 and 17 the variable speed pumps 1722, 1730, 1738, and 1752 (see FIG. 26) are operated to 18 maintain a constant basin temperature. The control of fan speed is based upon the 19 cooling tower design, predicted and actual process demand and historical environmental conditions with corrections for current process and environmental 21 conditions. Industrial computer 300 uses historical data to predict the process demand 22 for a current day based on historical process demand patterns and historical 23 environmental conditions, and then calculates a fan speed curve as a function of time.

1 The calculated fan speed curve represents the minimal energy required to operate the 2 fan throughout the variable speed range for that current day in order to meet the 3 constant basin temperature demand required by the industrial process. In real time, the 4 variable process control system processes the actual environmental conditions and industrial process demand and provides predictions and corrections that are used to 6 adjust the previously calculated fan speed curve as a function of time.
VFD device 22 7 outputs electrical power signals in accordance with the corrected fan speed curve. The 8 system utilizes logic based on current weather forecasts, from on-site weather station 9 316, as well as historical trends pertaining to past operating data, past process demand, and past environmental conditions (e.g. weather data, temperature and wet-bulb 11 temperature) to calculate the operating fan speed curve. In this Energy Optimization 12 Mode, the fan operation follows the changes in the daily wet-bulb temperature. Fan 13 operation is represented by a sine wave over a 24 hour period, as shown in the top 14 portion of the graph in FIG. 9, wherein the fan speed transitions are smooth and deliberate and follow a trend of acceleration and deceleration. In FIG. 9, the "Y" axis is 16 " Motor Speed" and the "X" axis is "Time". The fan speed curve in the top portion of the 17 graph in FIG. 9 (Energy Optimization Mode"is directly related to wet-bulb temperature.
18 The duration of time represented by the "X" axis is a twenty-four period. The variable 19 process control system of the present invention uses a Runge-Kutter algorithm that analyzes historical process demand and environmental stress as well as current 21 process demand and environmental stress to generate a fan speed curve that results in 22 energy savings. This control of the fan speed is therefore predictive in nature so as to 23 optimize energy consumption as opposed to being reactive to past data.
Such a 1 process minimizes the energy consumed in varying the fan speed. Such smooth fan 2 speed transitions of the present invention are totally contrary to the abrupt fan speed 3 transitions of the prior art fan drive systems, which are illustrated at the bottom of the 4 graph in FIG. 9. The fan speed transitions of the prior art fan drive system consist of numerous, abrupt fan-speed changes occurring over a twenty-four period in short 6 spurts. Such abrupt fan speed changes are the result of the prior art variable speed 7 logic which is constantly "switching" or accelerating and decelerating the fan to satisfy 8 the basin temperature set point.
9 Therefore, the Energy Optimization Mode of the present invention uses the cooling tower data, process demand, geographical location data, current environmental ii data and historical trends to predict fan speed according to loading so as to provide a 12 smooth fan-speed curve throughout the day. Such operation minimizes the fan speed 13 differential and results in optimized energy efficiency.

" S oft-S to p Mode"
16 The variable process control system and motor 20 of the present invention are 17 configured to operate in a "Soft-Stop Mode" of operation. In this mode of operation, 18 DAQ device 200 provides signals to VFD device 22 to cause VFD device 22 to 19 decelerate motor 20 under power RPM in accordance with a predetermined negative ramp rate to achieve a controlled stop. This mode of operation also eliminates 21 breakage of and/or damage to system components. This "Soft-Stop Mode"
quickly 22 brings the fan to a complete stop thereby reducing damage to the fan.
The particular 23 architecture of motor 20 allows the fan to be held at zero RPM to prevent the fan from 1 windmilling in reverse. Such a feature prevents the fan from damaging itself or 2 damaging other components during high winds and hurricanes. Such a "Soft Stop 3 Mode" of operation is not found in prior art fan drive systems using induction motors.

7 Fan Hold Mode 8 The variable process control system and motor 20 of the present invention are 9 configured to operate in a "Fan-Hold Mode". This mode of operation is used during a lock-out, tag-out (LOTO) procedure which is discussed in detail in the ensuing 11 description. "If a LOTO procedure is to be implemented, then motor 20 is first brought 12 to 0.00 RPM using the "Soft-Stop Mode", then the "Fan-Hold Mode" is implemented in 13 order to prevent the fan from windmilling. Fan-hold is a function of the design of 14 permanent magnet motor 20. DAQ device 200 provides signals to VFD device 22 to cause VFD device 22 to decelerate motor 20 under power at a predetermined negative 16 ramp rate to achieve a controlled stop of fan 12 in accordance with the "Soft-Stop 17 Mode". VFD device 22 controls motor 20 under power so that fan 12 is held stationary.
18 Next, the motor shaft 24 is locked with a locking mechanism (as will be described in the 19 ensuing description). Then, all forms of energy (e.g. electrical power) are removed according to the Lock-Out-Tag-Out (LOTO) procedure and then fan 12 can be secured.
21 In prior art drive systems using prior art induction motors, attempting to brake and hold 22 a fan would actually cause damage to the induction motor. However, such problems 23 are eliminated with the "Soft-Stop and "Fan-Hold Modes".

1 The variable process control system and motor 20 of the present invention can 2 also implement a "Reverse Operation Mode". In this mode of operation, motor 20 is 3 operated in reverse. This mode of operation is possible since there are no restrictions 4 or limitations on motor 20 unlike prior art gearbox fan drive systems which have many limitations (e.g. lubrication limitations). The unique bearing system of motor 20 allows 6 unlimited reverse rotation of motor 20. Specifically, the unique design of motor 20 7 allows design torque and speed in both directions.

9 Reverse Flying Start Mode The variable process control system and motor 20 of the present invention can ii also implement a "Reverse Flying-Start Mode" of operation. In this mode of operation, 12 the Flying Start mode of operation is implemented to obtain reverse rotation. The motor 13 20 is first decelerated under power until 0.00 RPM is attained than then reverse rotation 14 is immediately initiated. This mode of operation is possible since there are no restrictions or limitations on motor 20 in reverse. This mode of operation is useful for 16 de-icing.
17 Lock-Out Tag Out 18 In accordance with the invention, a particular Lock-Out Tag-Out (LOTO) 19 procedure is used to stop fan 12 in order to conduct maintenance on fan 12. A flow-chart of this procedure is shown in FIG. 16. Initially, the motor 20 is running at the 21 requested speed. In one embodiment, in order to initiate the LOTO
procedure, an 22 operator uses the built-in keypad of DAQ device 200 to implement "Soft-Stop Mode" so 23 as to cause motor 20, and thus fan 12, to decelerate to 0.0 RPM. Once the RPM of 1 motor 20 is at 0.0 RPM, the "Fan-Hold Mode" is implemented to allow VFD
device 22 2 and motor 20 hold the fan 12 at 0.0 RPM under power. A fan lock mechanism is then 3 applied to motor shaft 24. All forms of energy (e.g. electrical energy) are then removed 4 so as to lock out VFD 22 and motor 20. Operator or user interaction can then take place. The fan lock mechanism can be either manually, electrically, mechanically or 6 pneumatically operated, and either mounted to or built-in to motor 20.
This fan lock will 7 mechanically hold and lock the motor shaft 24 thereby preventing the fan 12 from 8 rotating when power is removed. Such a fan lock can be used for LOTO as well as 9 hurricane service. Fan lock configurations are discussed in the ensuing description.
Once the maintenance procedures are completed on the fan or cooling tower, all safety ii guards are replaced, the fan lock is released and the mechanical devices are returned 12 to normal operation. The operator then unlocks and powers up VFD device 22. Once 13 power is restored, the operator uses the keypad of DAQ device 200 to restart and 14 resume fan operation. This LOTO capability is a direct result of motor 20 being directly coupled to fan hub 16. The LOTO procedure provides reliable control of fan 12 and is 16 significantly safer than prior art techniques. This LOTO procedure complies with the 17 National Safety Council and OSHA guidelines for removal of all forms of energy.
18 One example of a fan lock mechanism that may be used on motor 20 is shown in 19 FIGS. 21A, 21 B and 21C. The fan lock mechanism is a solenoid-actuated pin-lock system and comprises enclosure or housing 1200, which protects the inner components 21 from environmental conditions, stop-pin 1202 and solenoid or actuator 1204. The 22 solenoid or actuator 1204 receives an electrical actuation signal from DAQ device 200 23 when it is desired to prevent fan rotation. The fan lock mechanism may be mounted on 1 the drive portion of motor shaft 24 that is adjacent the fan hub, or it may be mounted on 2 the lower, non-drive portion of the motor shaft 24. FIG. 21B shows solenoid 1204 so 3 that stop-pin 1202 engages rotatable shaft 24 of motor 20 so as to prevent rotation of 4 shaft 24 and the fan. In FIG. 21A, solenoid 1204 is deactivated so that stop pin 1202 is disengaged from rotatable shaft 24 so as to allow rotation of shaft 24 and the fan. FIG.
6 21C shows the fan-lock mechanism on both the upper, drive end of shaft 24, and the 7 lower, non-drive end of shaft 24.
8 In an alternate embodiment, the fan-lock mechanism shown in FIGS. 21A
and 9 21B can be cable-actuated. In a further embodiment, the fan-lock mechanism shown in FIGS. 21A and 21B is actuated by a flexible shaft. In yet another embodiment, the fan-ii mechanism shown in FIGS. 21A and 21B is motor-actuated.
12 Referring to FIG. 22, there is shown a caliper type fan-lock mechanism which can 13 be used with motor 20. This caliper type fan lock mechanism comprises cover 1300 14 and a caliper assembly, indicated by reference numbers 1302 and 1303.
The caliper type fan lock mechanism also includes discs 1304 and 1305, flexible shaft cover 1306 16 and a shaft or threaded rod 1308 that is disposed within the flexible shaft cover 1306.
17 The caliper type fan lock mechanism further includes fixed caliper block 1310 and 18 movable caliper block 1311. In an alternate embodiment, a cable is used in place of the 19 shaft or threaded rod 1308. In alternate embodiments, the fan lock mechanism can be activated by a motor (e.g. screw activated) or a pull-type locking solenoid.
FIG. 22 21 shows the fan lock mechanism mounted on top of the motor 20 so it can engage the 22 upper portion of motor shaft 24. FIG. 23 shows the fan lock mechanism mounted at the 23 bottom of motor 20 so the fan lock mechanism can engage the lower, non-drive end 25 1 of motor shaft 24. This caliper-type fan-lock mechanism comprises housing or cover 2 1400 and a caliper assembly, indicated by reference numbers 1402 and 1404. This 3 caliper-type fan-lock mechanism includes disc 1406, flexible shaft cover 1410 and shaft 4 or threaded rod 1408 that is disposed within the flexible shaft cover 1410.
Referring to FIG. 25, there is shown a band-type fan-lock mechanism which can 6 be used with motor 20. This band-type fan lock mechanism comprises cover 1600, 7 flexible shaft cover 1602 and a shaft or threaded rod 1604 that is disposed within the 8 flexible shaft cover 1604. The band-type fan lock mechanism further includes fixed 9 lock bands 1606 and 1610 and lock drum 1608. In an alternate embodiment, a cable is used in place of the shaft or threaded rod 1604. In alternate embodiments, the band-11 type fan lock mechanism can be activated by a motor (e.g. screw activated) or a pull-12 type locking solenoid. FIG. 25 shows the fan lock mechanism mounted on top of the 13 motor 20 so it can engage the upper portion of motor shaft 24. FIG. 24 shows the fan 14 lock mechanism mounted at the bottom of motor 20 so the fan lock mechanism can engage the lower, non-drive end 25 of motor shaft 24.
16 In another embodiment, the fan lock is configured as the fan lock described in 17 U.S. Patent Application Publication No. 2006/0292004, the disclosure of which 18 published application is hereby incorporated by reference.

De-Ice Mode 21 The variable process control system and motor 20 are also configured to 22 implement a "De-Ice Mode" of operation wherein the fan is operated in reverse. Icing of 23 the fans in a cooling tower may occur depending upon thermal demand (i.e. water from 1 the industrial process and the return demand) on the tower and environmental 2 conditions (i.e. temperature, wind and relative humidity). Operating cooling towers in 3 freezing weather is described in the January, 2007 "Technical Report", published by 4 SPX Cooling Technologies. The capability of motor 20 to operate in reverse in order to reverse the fan direction during cold weather will de-ice the tower faster and completely 6 by retaining warm air in the cooling tower as required by the environmental conditions.
7 Motor 20 can operate in reverse without limitations in speed and duration. However, 8 prior art gear boxes are not designed to operate in reverse due to the limitations of the 9 gearbox's bearing and lubrication systems. One prior art technique is to add lubrication pumps (electrical and gerotor) to the prior art gearbox in order to enable lubrication in 11 reverse operation. However, even with the addition of a lubrication pump, the 12 gearboxes are limited to very slow speeds and are limited to a typical duration of no 13 more than two minutes in reverse operation due to the bearing design.
For most 14 cooling towers, the fans operate continuously at 100% fan speed. In colder weather, the additional cooling resulting from the fans operating at 100% fan speed actually 16 causes the cooling tower to freeze which can lead to collapse of the tower. One prior 17 art technique utilized by cooling tower operators is the use of two-speed motors to drive 18 the fans. With such a prior art configuration, the two-speed motor is continually jogged 19 in a forward rotation and in a reverse rotation in the hopes of de-icing the tower. In some cases, the gearboxes are operated beyond the two minute interval in order to 21 perform de-icing. However, such a technique results in gearbox failure as well as icing 22 damage to the tower. If the motors are shut off to minimize freezing of the towers, the 23 fan and its mechanical system will ice and freeze. Another prior art technique is to de-1 ice the towers late at night with fire hoses that draw water from the cooling tower basin.
2 However, this is a dangerous practice and often leads to injuries to personnel. In order 3 to solve the problems of icing in a manner that eliminates the problems of prior art de-4 icing techniques, the present invention implements an automatic de-icing operation without operator involvement and is based upon the cooling tower thermal design, 6 thermal gradient data, ambient temperature, relative humidity, wet-bulb temperature, 7 wind speed and direction. Due to the bearing design and architecture of motor 20 and 8 design torque, fan 12 is able to rotate in either direction (forward or reverse). This 9 important feature enables the fan 12 to be rotated in reverse for purposes of de-icing.
DAQ device 200 and VFD device 22 are configured to operate motor 20 at variable ii speed which will reduce icing in colder weather. This variable speed characteristic 12 combined with design torque and fan speed operation in forward or reverse minimizes 13 and eliminates icing of the tower. DAQ device 200 is programmed with temperature set 14 points, tower design parameters, plant thermal loading, and environmental conditions and uses this programmed data and the measured temperature values provided by the 16 temperature sensors to determine if de-icing is necessary. If DAQ device 17 determines that de-icing is necessary, then the de-icing mode is automatically initiated 18 without operator involvement. When such environmental conditions exist, DAQ device 19 200 generates control signals that cause VFD device 22 to ramp down the RPM of motor 20 to 0.0 RPM. The Soft-Stop Mode can be used to ramp the motor RPM down 21 to 0.00 RPM. Next, the motor 20 is operated in reverse so as to rotate the fan 12 in 22 reverse so as to de-ice the cooling tower. The Reverse Flying Start mode can be used 23 to implement de-icing. Since motor 20 does not have the limitations of prior art 1 gearboxes, supervision in this automatic de-ice mode is not necessary.
Upon initiation 2 of de-icing, DAQ device 200 issues a signal to industrial computer 300.
In response, 3 display screen 306 displays a notice that informs the operators of the de-icing operation.
4 This de-icing function is possible because motor 20 comprises a unique bearing design and lubrication system that allows unlimited reverse operation (i.e. 100% fan speed in 6 reverse) without duration limitations. The unlimited reverse operation in combination 7 with variable speed provides operators or end users with infinite speed range in both 8 directions to match ever changing environmental stress (wind and temperatures) while 9 meeting process demand. Since DAQ device 200 can be programmed, the de-icing program may be tailored to the specific design of a cooling tower, the plant thermal ii loading and the surrounding environment. In a preferred embodiment, DAQ
device 200 12 generates email or SMS text messages to notify the operators of initiation of the de-ice 13 mode. In a preferred embodiment, DAQ device 200 generates a de-icing schedule 14 based on the cooling tower design, the real time temperature, wet-bulb temperature, wind speed and direction, and other environmental conditions. In an alternate 16 embodiment, temperature devices maybe installed within the tower to monitor the 17 progress of the de-icing operation or to trigger other events. The variable process 18 control system of the present invention is configured to allow an operator to manually 19 initiate the De-Ice mode of operation. The software of the DAQ device 200 and industrial computer 300 allows the operator to use either the keypad at the DAQ device 21 200, or user input device 304 which is in data signal communication with industrial 22 computer 300. In alternate embodiment, the operator initiates the De-Icing mode via 23 Distributed Control System 315. In such an embodiment, the control signals are routed 1 to industrial computer 300 and then DAQ device 200.
2 In a multi-cell system, there is a separate VFD device for each permanent 3 magnet motor but only one DAQ device for all of the cells. This means that every 4 permanent magnet motor, whether driving a fan or part a variable speed pump, will receive control signals from a separate, independent, dedicated VFD device.
Such a 6 multi-cell system is described in detail in the ensuing description. The DAQ device is 7 programmed with the same data as described in the foregoing description and further 8 includes data representing the number of cells. The DAQ device controls each cell 9 individually such that certain cells may be dwelled, idled, held at stop or allowed to windmill while others may function in reverse at a particular speed to de-ice the tower 11 depending upon the particular design of the cooling tower, outside temperature, wet 12 bulb, relative humidity, wind speed and direction. Thus, the DAQ device determines 13 which cells will be operated in the de-ice mode. Specifically, DAQ
device 200 is 14 programmed so that certain cells will automatically start de-icing the tower by running in reverse based upon the cooling tower design requirements. Thus, the fan in each cell 16 can be operated independently to retain heat in the tower for de-icing while maintaining 17 process demand.
18 In either the single fan cooling tower, or a multi-cell tower, temperature sensors 19 in the cooling towers provide temperature data to the DAQ device 200 processes these signals to determine if the De-Ice mode should be implemented. In a multi-cell tower, 21 certain cells may need de-icing and other cells may not. In that case, the DAQ device 22 sends the de-icing signals to only the VFDs that correspond to fan cells requiring de-23 icing.

1 The DAQ device is also programmed to provide operators with the option of just 2 reducing the speed of the fans in order to achieve some level of de-icing without having 3 to stop the fans and then operate in reverse.
4 In another embodiment of the invention, VFD device 22 is configured as a regenerative (ReGen) drive device. A regenerative VFD is a special type of VFD
with 6 power electronics that return power to the power grid. Such a regenerative drive 7 system captures any energy resulting from the fan "windmilling" and returns this energy 8 back to the power grid. "Windmilling" occurs when the fan is not powered but is rotating 9 in reverse due to the updraft through the cooling tower. The updraft is caused by water in the cell. Power generated from windmilling can also be used to limit fan speed and 11 prevent the fan from turning during high winds, tornados and hurricanes.
The 12 regenerative VFD device is also configured to generate control signals to motor 20 that 13 to hold the fan at 0.00 RPM so as to prevent windmilling in high winds such as those 14 experienced during hurricanes.
Referring to FIG. 2, the variable process control system of the present invention 16 further comprises a plurality of sensors and other measurement devices that are in 17 electrical signal communication with DAQ device 200. Each of these sensors has a 18 specific function. Each of these functions is now described in detail.
Referring to FIG. 4 19 and 5B, motor 20 includes vibration sensors 400 and 402 which are located within motor casing 21. Sensor 400 is positioned on bearing housing 50 and sensor 402 is 21 positioned on bearing housing 52. In a preferred embodiment, each sensor 400 and 22 402 is configured as an accelerometer, velocity and displacement. As described in the 23 foregoing description, sensors 400 and 402 are electrically connected to quick-1 disconnect adapter 108 and cable 110 is electrically connected to quick-disconnect 2 adapter 108 and communication data junction box 111. Cable 112 is electrically 3 connected between communication data junction box 111 and DAQ device 200.
4 Vibration sensors 400 and 402 provide signals that represent vibrations experienced by fan 12. Vibrations caused by a particular source or condition have a unique signature.
6 All signals emanating from sensors 400 and 402 are inputted into DAQ
device 200 7 which processes these sensor signals. Specifically, DAQ device 200 includes a 8 processor that executes predetermined vibration- analysis algorithms that process the 9 signals provided by sensors 400 and 402 to determine the signature and source of the vibrations. Such vibration-analysis algorithms include a FFT (Fast Fourier Transform).
ii Possible reasons for the vibrations may be an unbalanced fan 12, instability of motor 12 20, deformation or damage to the fan system, resonant frequencies caused by a 13 particular motor RPM, or instability of the fan support structure, e.g.
deck. If DAQ
14 device 200 determines that the vibrations sensed by sensors 400 and 402 are caused by a particular RPM of motor 20, DAQ device 200 generates a lock-out signal for input 16 to VFD device 22. The lock-out signal controls VFD device 22 to lock out the particular 17 motor speed (or speeds) that caused the resonant vibrations. Thus, the lock-out signals 18 prevent motor 20 from operating at this particular speed (RPM). DAQ
device 200 also 19 issues signals that notify the operator via DCS 315. It is possible that there may be more than one resonant frequency and in such a case, all motor speeds causing such 21 resonant frequencies are locked out. Thus, the motor 20 will not operate at the speeds 22 (RPM) that cause these resonant frequencies. Resonant frequencies may change over 23 time. However, vibration sensors 400 and 402, VFD device 22 and DAQ
device 200 1 constitute an adaptive system that adapts to the changing resonant frequencies. The 2 processing of the vibration signals by DAQ device 200 may also determine that fan 3 balancing may be required or that fan blades need to be re-pitched.
4 Fan trim balancing is performed at commissioning to identify fan imbalance, which is typically a dynamic imbalance. Static balance is the norm. Most fans are not 6 dynamically balanced. This imbalance causes the fan to oscillate which results in wear 7 and tear on the tower, especially the bolted joints. In prior art fan drive systems, 8 measuring fan imbalance can be performed but requires external instrumentation to be 9 applied to the outside of the prior art gearbox. This technique requires entering the cell.
However, unlike the prior art systems, DAQ device 200 continuously receives signals ii outputted by vibration sensors 400 and 402. Dynamic system vibration can be caused 12 by irregular fan pitch, fan weight and or installation irregularities on the multiple fan 13 blade systems. Fan pitch is usually set by an inclinometer at commissioning and can 14 change over time causing fan imbalance. If the pitch of any of the fan blades 18 deviates from a predetermined pitch or predetermined range of pitches, then a 16 maintenance action will be performed on fan blades 18 in order to re-pitch or balance 17 the blades. In a preferred embodiment, additional vibration sensors 404 and 406 are 18 located on bearing housings 50 and 52, respectively, of motor 20 (see FIG. 4). Each 19 vibration sensor 404 and 406 is configured as an accelerometer or a velocity probe or a displacement probe. Each vibration sensor 404 and 406 has a particular sensitivity and 21 a high fidelity that is appropriate for detecting vibrations resulting from fan imbalance.
22 Signals emanating from sensors 404 and 406 are inputted into DAQ device 200 via 23 cable 110, communication data junction box 111 and cable 112. Sensors 404 and 406 1 provide data that allows the operators to implement correct fan trim balancing. Fan trim 2 balancing provides a dynamic balance of fan 12 that extends cooling tower life by 3 reducing or eliminating oscillation forces or the dynamic couple that causes wear and 4 tear on structural components caused by rotating systems that have not been dynamically balanced. If the measured vibrations indicate fan imbalance or are 6 considered to be in a range of serious or dangerous vibrations indicating damaged 7 blades or impending failure, then DAQ device 200 automatically issues an emergency 8 stop signal to VFD device 20. If the vibrations are serious, then DAQ
device 200 issues 9 control signals to VFD device 22 that causes motor 20 to coast to a stop.
The fan would be held using the Fan-Hold mode of operation. Appropriate fan locking mechanisms ii would be applied to the motor shaft 24 so that the fan could be inspected and serviced.
12 DAQ device 200 then issues alert notification via email or SMS text messages to the 13 DCS 315 to inform the operators that then fan has been stopped due to serious 14 vibrations. DAQ device 200 also issues the notification to industrial computer 300 for display on display 306. If the vibration signals indicate fan imbalance but the imbalance 16 is not of a serious nature, DAQ device 200 issues a notification to the DCS 315 to alert 17 the operators of the fan imbalance. The operators would have the option cease 18 operation of the cooling tower or fan cell so that the fan can be inspected and serviced if 19 necessary. Thus, the adaptive vibration-monitoring and compensation function of the variable process control system of the present invention combines with the bearing 21 design and structure of motor 20 to provide low speed, dynamic fan trim balance 22 thereby eliminating the "vibration couple".
23 The adaptive vibration feature of the variable process control system provides 1 100% monitoring, supervision and control of the direct drive fan system with the 2 capability to issue reports and alerts to DCS 315 via e-mail and SMS.
Such reports and 3 alerts notify operators of operating imbalances, such as pitch and fan imbalance. Large 4 vibrations associated with fan and hub failures, which typically occur within a certain vibration spectrum, will result in motor 20 being allowed to immediately coast down to 6 0.0 RPM. The fan-hold mode is then implemented. Industrial computer 300 then 7 implements FFT processing of the vibration signals in order to determine the cause of 8 the vibrations and to facilitate prediction of impeding failures. As part of this processing, 9 the vibration signals are also compared to historic trending data in order to facilitate understanding and explanation of the cause of the vibrations.
ii In an alternate embodiment, the variable process control system of the present 12 invention uses convenient signal pick-up connectors at several locations outside the fan 13 stack. These signal pick-up connectors are in signal communication with sensors 400 14 and 402 and can be used by operators to manually plug in balancing equipment (e.g.
Emerson CSI 2130) for purposes of fan trim.
16 In accordance with the invention, when sensors 400, 402, 404 and 406 are 17 functioning properly, the sensors output periodic status signals to DAQ
device 200 in 18 order to inform the operators that sensors 400, 402, 404 and 406 are working properly.
19 If a sensor does not emit a status signal, DAQ device 200 outputs a sensor failure notification that is routed to DCS 315 via email or SMS text messages. The sensor 21 failure notifications are also displayed on display screen 306 to notify the operators of 22 the sensor failure. Thus, as a result of the continuous 100% monitoring of the sensors, 23 lost sensor signals or bad sensor signals will cause an alert to be issued and displayed 1 to the operators. This feature is a significant improvement over prior art systems which 2 require an operator to periodically inspect vibration sensors to ensure they are working 3 properly. When a sensor fails in a prior art fan drive system, there is no feedback or 4 indication to the operator that the sensor has failed. Such deficiencies can lead to catastrophic results such as catastrophic fan failure and loss of the cooling tower asset.
6 However, the present invention significantly reduces the chances of such catastrophic 7 incidents from ever occurring. In the present invention, there is built-in redundancy with 8 respect to the sensors. In a preferred embodiment, all sensors are Line Replaceable 9 Units (LRU) that can easily be replaced. In a preferred embodiment, the Line Replaceable Units utilize area classified Quick Disconnect Adapters such as the Turck ii Multifast Right Angle Stainless Connector with Lokfast Guard, which was described in 12 the foregoing description.
13 Examples of line replaceable vibration sensor units that are used to detect 14 vibrations at motor 20 are shown in FIGS. 18, 19 and 20. Referring to FIG. 18, there is shown a line-replaceable vibration sensor unit that is in signal communication with 16 instrument junction box 900 that is connected to motor housing or casing 21. This 17 vibration sensor unit comprises cable gland 902, accelerometer cable 904 which 18 extends across the exterior surface of the upper portion 906 of motor casing 21.
19 Accelerometer 908 is connected to upper portion 906 of motor casing 21.
In a preferred embodiment, accelerometer 908 is connected to upper portion 906 of motor casing 21 21 with a Quick Disconnect Adapters such as the Turck Multifast Right Angle Stainless 22 Connector with Lokfast Guard which was described in the foregoing description.
23 Sensor signals from accelerometer 908 are received by DAQ device 200 for processing.

1 In a preferred embodiment, sensor signals from accelerometer 908 are provided to DAQ
2 device 200 via instrument junction box 900. In such an embodiment, instrument 3 junction box 900 is hardwired to DAQ device 200.
4 Another line-replaceable vibration sensor unit is shown in FIG. 19. This line-s replaceable vibration sensor unit that is in signal communication with instrument 6 junction box 900 that is connected to motor housing or casing 21 and comprises cable 7 gland 1002, and accelerometer cable 1004 which extends across the exterior surface of 8 the upper portion 1006 of motor casing 21. This vibration sensor unit further comprises 9 accelerometer 1008 that is joined to upper portion 1006 of motor casing 21.
Accelerometer 1008 is joined to upper portion 1006 of motor casing 21. In a preferred 11 embodiment, accelerometer 1008 is hermetically sealed to upper portion 1006 of motor 12 casing 21. Sensor signals from accelerometer 1008 are received by DAQ
device 200 13 for processing. In one embodiment, sensor signals from accelerometer 1008 are 14 provided to DAQ device 200 via instrument junction box 900. In such an embodiment, instrument junction box 900 is hardwired to DAQ device 200.
16 Another line-replaceable vibration sensor unit is shown in FIG. 20. This line-17 replaceable vibration sensor unit that is in signal communication with instrument 18 junction box 900 that is connected to motor housing or casing 21 and comprises cable 19 gland 1102, and accelerometer cable 1104 which extends across the exterior surface of the upper portion 1110 of motor casing 21. This vibration sensor unit further comprises 21 accelerometer 1108 that is joined to upper portion 1110 of motor casing 21.
22 Accelerometer 1108 is joined to upper portion 1100 of motor casing 21.
In a preferred 23 embodiment, accelerometer 1108 is hermetically sealed to upper portion 1100 of motor 1 casing 21. Sensor signals from accelerometer 1108 are received by DAQ
device 200 for 2 processing. In one embodiment, sensor signals from accelerometer 1108 are provided 3 to DAQ device 200 via instrument junction box 900. In such an embodiment, instrument 4 junction box 900 is hardwired to DAQ device 200.
It is to be understood that in alternate embodiments, one or more vibrations 6 sensors can be mounted to the motor structure, or mounted to the exterior of the motor, 7 or mounted on the exterior of the motor housing or casing, or mounted to 8 instrumentation boxes or panels that are attached to the exterior of the motor. In an 9 alternate embodiment, additional vibration sensors can be mounted to the cooling tower structure at various locations.
11 Referring to FIGS. 2 and 4, the variable process control system of the present 12 invention further comprises a plurality of temperature sensors that are positioned at 13 different locations within the variable process control system and within cooling 14 apparatus 10. In a preferred embodiment, each temperature sensor comprises a commercially available temperature probe. Each temperature sensor is in electrical 16 signal communication with communication data junction box 111.
Temperature sensors 17 located within motor casing 21 are electrically connected to quick-disconnect adapter 18 108 which is in electrical signal communication with communication data junction box 19 111 via wires 110. The temperature sensors that are not located within motor casing 21 are directly hardwired to communication data junction box 111. The functions of these 21 sensors are as follows:
22 1) sensor 420 measure the temperature of the interior of motor casing 21 (see 23 FIG. 4);

1 2) sensors 421A and 421B measure the temperature of the motor bearing 2 housings 50 and 52, respectively (see FIG. 4);
3 3) sensor 422 measures the temperature of stator 32, the end turns of the coils 4 or windings, the laminations, etc. that are within the motor casing 21 (see FIG. 4);
6 4) sensor 426 is located near motor casing 21 to measure the ambient 7 temperature of the air surrounding motor 20 (see FIG. 2);
8 5) sensor 428 is located in a collection basin (not shown) of a wet-cooling tower 9 to measure the temperature of the water in the collection basin (see FIG. 2);
6) sensor 430 measures the temperature at DAQ device 200 (see FIGS. 2 and 11 4);
12 7) sensor 432 measures the wet-bulb temperature (see FIG. 2);
13 8) sensor 433 measures the temperature of the airflow created by the fan (see 14 FIG. 4);
9) sensor 434 measures the external temperature of the motor casing (see FIG.
16 4);
17 10) sensor 435 detects gas leaks or other emissions (see FIG. 4).
18 In a preferred embodiment, there is a plurality of sensors that perform each of the 19 aforesaid tasks. For example, in one embodiment, there are is plurality of sensors 428 that measure the temperature of the water in the collection basin.
21 Sensors 426, 428, 430, 432, 433, 434 and 435 are hard wired directly to 22 communication data junction box 111 and the signals provided by these sensors are 23 provided to DAQ device 200 via cable 112. Since sensors 421A, 421B and 422 are 1 within motor casing 21, the signals from these sensors are fed to quick-disconnect 2 adapter 108. The internal wires in motor 20 are not shown in FIG. 2 in order to simplify 3 the diagram shown in FIG. 2. A sudden rise in the temperatures of motor casing 21 or 4 motor stator 32 (stator, rotor, laminations, coil, end turns) indicates a loss of airflow and/or the cessation of water to the cell. If such an event occurs, DAQ device 6 issues a notification to the plant DCS 315 and also simultaneously activates alarms, 7 such as alarm device 438 (see FIG. 2), and also outputs a signal to industrial computer 8 300. This feature provides a safety mechanism to prevent motor 20 from overheating.
9 In an alternate embodiment, sensor 430 is not hardwired to communication data junction box 111, but instead, is directly wired to the appropriate input of DAQ device ii 200.

Thus, DAQ device 200, using the aforesaid sensors, measures the parameters 13 set forth in Table I:

Parameter Measured Purpose Internal motor temperature: end turns, coil Monitoring, supervision, health analysis;
lamination, stator, internal air and magnets detect motor overheating; detect wear or damage of coil, stator, magnets; detect lack of water in cell External motor temperature Monitoring, supervision, health analysis;
detect motor overheating; detect lack of water in cell Bearing Temperature Monitoring, supervision, health analysis;
detect bearing wear or impending failure;
detect lubrication issues; FFT processing Fan Stack Temperature Monitoring, supervision, health analysis;
determine Cooling Tower Thermal Capacity; determine existence of icing;
operational analysis Plenum Pressure Monitoring, supervision, health analysis;
plenum pressure equated to fan inlet pressure for mass airflow calculation Motor Load Cells Determine fan yaw loads; system weight;
assess bearing life; FFT processing Bearing Vibration Monitoring, supervision, health analysis;
trim balance; adaptive vibration monitoring; modal testing Gas Leaks or Emissions Monitoring, supervision, health analysis;
detect fugitive gas emissions; monitoring heat exchanger and condenser for gas emissions 2 The desired temperature of the liquid in the collection basin, also known as the 3 basin temperature set-point, can be changed by the operators instantaneously to meet 4 additional cooling requirements such as cracking heavier crude, maintain vacuum backpressure in a steam turbine, prevent fouling of the heat exchanger or to derate the 6 plant to part-load. Industrial computer 300 is in electronic signal communication with 7 the plant DCS (Distributed Control System) 315 (see FIG. 2). The operators use plant 8 DCS 315 to input the revised basin temperature set-point into industrial computer 300.
9 Industrial computer 300 communicated this information to DAQ device 200.
Sensor 428 continuously measures the temperature of the liquid in the collection basin in order to 11 determine if the measure temperature is above or below the basin temperature set-12 point. DAQ device 200 processes the temperature data provided by sensor 428, the 13 revised basin temperature set point, the current weather conditions, thermal and 14 process load, and pertinent historical data corresponding to weather, time of year and time of day.
16 In one embodiment, wet-bulb temperature is measured with suitable 17 instrumentation such as psychrometers, thermohygrometers or hygrometers which are 18 known in the art.

1 As a result of the adaptive characteristics of the variable process control system 2 of the present invention, a constant basin temperature is maintained despite changes in 3 process load, Cooling Tower Thermal Capacity, weather conditions or time of day.
4 DAQ device 200 continuously generates updated sinusoidal fan speed curve in response to the changing process load, Cooling Tower Thermal Capacity, weather 6 conditions or time of day.
7 Temperature sensor 430 measures the temperature at DAQ device 200 in order 8 to detect overheating cause by electrical overload, short circuits or electronic 9 component failure. In a preferred embodiment, if overheating occurs at DAQ device 200, then DAQ device 200 issues an emergency stop signal to VFD device 22 to initiate 11 an emergency "Soft Stop Mode" to decelerate motor 20 to 0.00 RPM and to activate 12 alarms (e.g. alarm 438, audio alarm, buzzer, siren, horn, flashing light, email and text 13 messages to DCS 315, etc.) to alert operators to the fact that the system is attempting 14 an emergency shut-down procedure due to excessive temperatures. In one embodiment of the present invention, if overheating occurs at DAQ device 200, DAQ
16 device 200 issues a signal to VFD device 22 to maintain the speed of motor 20 at the 17 current speed until the instrumentation can be inspected.
18 The operating parameters of motor 20 and the cooling tower are programmed 19 into DAQ device 200. DAQ device 200 comprises a microprocessor or mini-computer and has computer processing power. Many of the operating parameters are defined 21 over time and are based on the operating tolerances of the system components, fan 22 and tower structure. Gradual heating of motor 20 (stator, rotor, laminations, coil, end 23 turns, etc.) in small increments as determined by trending over months, etc. as 1 compared with changes (i.e. reductions) in horsepower or fan torque over the same 2 time interval, may indicate problems in the cooling tower such as clogged fill, poor water 3 distribution, etc. Industrial computer 300 will trend the data and make a decision as to 4 whether to display a notice on display 306 that notifies the operators that an inspection of the cooling tower is necessary. A sudden rise in motor temperature as a function of 6 time may indicate that the cell water has been shut-off. Such a scenario will trigger an 7 inspection of the tower. The variable process control system of the present invention is 8 designed to notify operators of any deviation from operating parameters.
When 9 deviations from these operating parameters and tolerances occur (relative to time), DAQ device 200 issues signals to the operators in order to notify them of the conditions ii and that an inspection is necessary. Relative large deviations from the operating 12 parameters, such as large vibration spike or very high motor temperature, would cause 13 DAQ device 200 to generate a control signal to VFD device 22 that will enable motor 20 14 to coast to complete stop. The fan is then held by the Fan Hold mode of operation.
DAQ device 200 simultaneously issues alerts and notifications via email and/or text 16 messages to DCS 315.
17 As described in the foregoing description, VFD device 22, DAQ device 200 and 18 industrial computer 300 are housed in Motor Control Enclosure (MCE) 26.
The variable 19 process control system includes a purge system that maintains a continuous positive pressure on cabinet 26 in order to prevent potentially explosive gases from being drawn 21 into MCE 26. Such gases may originate from the heat exchanger. The purge system 22 comprises a compressed air source and a device (e.g. hose) for delivering a continuous 23 source of pressurized air to MCE 26 in order to create a positive pressure which 1 prevents entry of such explosive gases. In an alternate embodiment, MCE
26 is cooled 2 with Vortex coolers that utilize compressed air. In a further embodiment, area classified 3 air conditioners are used to deliver airflow to MCE 26.
4 Referring to FIG. 2, in a preferred embodiment, the system of the present invention further includes at least one pressure measurement device 440 that is located 6 on the fan deck and which measures the pressure in the cooling tower plenum. In a 7 preferred embodiment, there is a plurality of pressure measurement devices 400 to 8 measure the pressure in the cooling tower plenum. Each pressure measurement 9 device 440 is electrically connected to communication data junction box 111. The measured pressure equates to the pressure before the fan (i.e. fan inlet pressure). The ii measured pressure is used to derive fan pressure for use in cooling performance 12 analysis.
13 It is critical that the fan be located at the correct fan height in order to produce the 14 requisite amount of design fan pressure. The fan must operate at the narrow part of the fan stack in order to operate correctly, as shown in FIG. 13. Many prior art fan drive 16 systems do not maintain the correct fan height within the existing parabolic fan stack 17 installation. Such a misalignment in height causes significant degradation in cooling 18 capacity and efficiency. An important feature of the load bearing direct drive fan system 19 of the present invention is that the design architecture of motor 20 maintains or corrects the fan height in the fan stack. Referring to FIGS. 13 and 14, there is shown a diagram 21 of a wet cooling tower that uses the load bearing direct drive fan system of the present 22 invention. The wet cooling tower comprises fan stack 14 and fan deck 250. Fan stack 23 14 is supported by fan deck 250. Fan stack 14 has a generally parabolic shape. In 1 other embodiments, fan stack 14 can have a straight cylinder shape (i.e.
cylindrical 2 shape). Fan stack 14 and fan deck 250 were discussed in the foregoing description. A
3 parabolic fan stack 14 requires that the motor height accomodate the proper fan height 4 in the narrow throat section of fan stack 14 in order to seal the end of the fan blade at the narrow point of the parabolic fan stack 14. This assures that the fan will operate 6 correctly and provide the proper fan pump head for the application. The wet cooling 7 tower includes fan assembly 12 which was described in the foregoing description. Fan 8 assembly 12 comprises fan hub 16 and fan blades 18 that are connected to fan hub 16.
9 Fan assembly 12 further comprises fan seal disk 254 that is connected to the top of fan hub 16. Fan hub 16 has a tapered bore 255. Motor 20 has a locking keyed shaft ii which interfaces with a complementary shaped portion of tapered bore 255.
12 Specifically, as shown in FIG. 14, motor shaft 24 is configured to have a key channel 13 256 that receives a complementary shaped portion of fan hub 16. Tapered bushing 257 14 is fastened to motor shaft 24 with set screw 258 so as to prevent movement of tapered bushing 257. The height H indicates the correct height at which the fan blades 16 should be located (see FIG. 13) within fan stack 14. The height H
indicates the 17 uppermost point of the narrow portion of fan stack 14. This is the correct height at 18 which the fan blades 18 should be located in order for the fan assembly 12 to operate 19 properly and efficiently. An optional adapter plate 260 can be used to accurately position the fan blades 18 at the correct height H (see FIGS. 13 and 14).
Retrofitting 21 motor 20 and adapter plate 260, as required, and correcting fan height can actually 22 increase airflow through the cooling tower by setting the fan assembly 12 at the correct 23 height H. Adapter plate 260 is positioned between ladder frame/torque tube 262 and 1 motor 20 such that motor 20 is seated upon and connected to adapter plate 260. Motor 2 20 is connected to a ladder frame or torque tube or other suitable metal frame that 3 extends over the central opening in the fan deck 250. Motor 20 is designed such that 4 only four bolts are needed to connect motor 20 to the existing ladder frame or torque tube. As shown in FIG. 12B, motor housing 21 has four holes 264A, 264B, 264C
and 6 264D extending therethrough to receive four mounting bolts. Adapter plate 260 is 7 designed with corresponding through-holes that receive the aforementioned four bolts.
8 The four bolts extend through corresponding openings 264A, 264B, 264C and 9 through the corresponding openings in adapter plate 260 and through corresponding openings in the ladder frame or torque tube. Thus, by design, the architecture of motor ii 20 is designed to be a drop-in replacement for all prior art gearboxes (see FIG. 1) and 12 maintains or corrects fan height in the fan stack 14 without structural modifications to 13 the cooling tower or existing ladder frame or torque tubes. Such a feature and 14 advantage is possible because motor 20 is designed to have a weight that is the same or less than the prior art gearbox system it replaces. The mounting configuration of 16 motor 20 (see FIG. 12B) allows motor 20 to be mounted to existing interfaces on 17 existing structural ladder frames and torque tubes and operate within the fan stack 18 meeting Area Classification for Class 1, Div. 2, Groups B, C, D.
Therefore, new or 19 additional ladder frames and torque tubes are not required when replacing a prior art gearbox system with motor 20. Since motor 20 has a weight that is the same or less 21 than the prior art gearbox it replaces, motor 20 maintains the same weight distribution 22 on the existing ladder frame or torque tube 262. Motor 20 is connected to fan hub 16 in 23 the same way as a prior art gearbox is connected to fan hub 16. The only components 1 needed to install motor 20 are: (a) motor 20 having power cable 105 wired thereto as 2 described in the foregoing description, wherein the other end of power cable 105 is 3 adapted to be electrically connected to motor disconnect junction box 106, (b) the four 4 bolts that are inserted into through-holes 264A, 264B, 264C and 264D in motor casing or housing 21, (c) cable 110 having one terminated at a quick-disconnect adapter 108, 6 and the other end adapted to be electrically connected to communication data junction 7 box 111(d) power cable 107 which is adapted to be electrically connected to motor 8 disconnect junction box 106 and VFD device 22. Power cables 105 and 107 were 9 described in the foregoing description. As a result of the design of motor 20, the process of replacing a prior art drive system with motor 20 is simple, expedient, requires ii relatively less crane hours, and requires relatively less skilled labor than required to 12 install and align the complex, prior art gearboxes, shafts and couplings. In a preferred 13 embodiment, motor 20 includes lifting lugs or hooks 270 that are rigidly connected to or 14 integrally formed with motor housing 21. These lifting lugs 270 are located at predetermined locations on motor housing 21 so that motor 20 is balanced when being 16 lifted by a crane during the installation process. Motor 20 and its mounting interfaces 17 have been specifically designed for Thrust, Pitch, Yaw, reverse loads and fan weight 18 (dead load).
19 Thus, motor 20 is specifically designed to fit within the installation envelope of an existing, prior art gearbox and maintain or correct the fan height in the fan stack. In one 21 embodiment, the weight of motor 20 is less than or equal to the weight of the currently-22 used motor-shaft-gearbox drive system. In a preferred embodiment of the invention, the 23 weight of motor 20 does not exceed 2500 lbs. In one embodiment, motor 20 has a 1 weight of approximately 2350 lbs. Motor shaft 24 has been specifically designed to 2 match existing interfaces with fan-hub shaft diameter size, profile and keyway. Motor 3 20 can rotate all hubs and attaching fans regardless of direction, blade length, fan 4 solidity, blade profile, blade dimension, blade pitch, blade torque, and fan speed.
It is to be understood that motor 20 may be used with other models or types of 6 cooling tower fans. For example, motor 20 may be used with any of the commercially 7 available 4000 Series Tuft-Lite Fans manufactured by Hudson Products, Corporation of 8 Houston, Texas. In an alternate embodiment, motor 20 is connected to a fan that is 9 configured without a hub structure. Such fans are known are whisper-quiet fans or single-piece wide chord fans. The single-piece wide chord fan operates at slower ii speeds for noise attenuation. The single-piece wide chord fan has no fan hub and is of 12 a direct-bolt configuration. When single-piece wide chord fans are used, rotatable motor 13 shaft 24 is directly bolted or connected to the fan. One commercially available whisper-14 quiet fan is the PT2 Cooling Tower Whisper Quiet Fan manufactured by Baltimore Aircoil Company of Jessup, Maryland.
16 Motor 20 is designed to withstand the harsh chemical attack, poor water quality, 17 mineral deposits and pH attack, biological growth, and humid environment without 18 contaminating the lubrication system or degrading the integrity of motor 20. Motor 20 19 operates within the fan stack and does not require additional cooling ducts or flow scoops.
21 For a new installation (i.e. newly constructed cooling tower), the installation of 22 motor 20 does not require ladder frames and torque tubes as do prior art gearbox 23 systems. The elimination of ladder frames and torque tubes provides a simpler 1 structure at a reduced installation costs. The elimination of the ladder frame and torque 2 tubes significantly reduces obstruction and blockage from the support structure thereby 3 reducing airflow loss. The elimination of ladder frames and torque tubes also reduce 4 fan pressure loss and turbulence. The installation of motor 20 therefore is greatly simplified and eliminates multiple components, tedious alignments, and also reduces 6 installation time, manpower and the level of skill of the personnel installing motor 20.
7 The electrical power is simply connected at motor junction box 106. The present 8 invention eliminates shaft penetration through the fan stack thereby improving fan 9 performance by reducing airflow loss and fan pressure loss.
As described in the foregoing description, cable 105 is terminated or prewired at ii motor 20 during the assembly of motor 20. Such a configuration simplifies the 12 installation of motor 20. Otherwise, confined-space entry training and permits would be 13 required for an electrician to enter the cell to install cable 105 to motor 20. Furthermore, 14 terminating cable 105 to motor 20 during the manufacturing process provides improved reliability and sealing of motor 20 since the cable 105 is assembled and terminated at 16 motor 20 under clean conditions, with proper lighting and under process and quality 17 control. If motor 20 is configured as a three-phase motor, then cable 105 is comprised 18 of three wires and these three wires are to be connected to the internal wiring within 19 motor disconnect junction box 106.
Test Results 21 The system of the present invention was implemented with a wet-cooling 22 tower system. Extensive Beta Testing was conducted on the system with 23 particular attention being directed to vibrations and vibration analysis.
24 FIG. 11A is a bearing vibration report, in graph form, which resulted from a beta test of the system of the present invention. FIG. 11B is the same 26 bearing vibration report of FIG. 11A and shows a prior art (i.e.
gearbox) 1 trip value of 0.024G. FIG. 11C is a vibration severity graph showing the 2 level of vibrations generated by the system of the present invention.
3 These test results reveal motor 20 and its drive system operate 4 significantly smoother than the prior art gearbox systems thereby producing a significantly lower vibration signature. Such smooth operation 6 is due to the unique bearing architecture of motor 20. The average 7 operating range of the motor 20 is 0.002G with peaks of 0.005G as 8 opposed to the average prior art gearbox trip value of 0.024G.

The aforementioned smooth operation of motor 20 and its drive system allows ii accurate control, supervision, monitoring and system-health management because the 12 variable process control system of the present invention is more robust.
On the other 13 hand, prior art gear-train meshes (i.e. motor, shaft, couplings and subsequent multiple 14 gear-train signatures) have multiple vibration signatures and resultant cross-frequency noise that are difficult to identify and manage effectively. Motor 20 increases airflow 16 through a cooling tower by converting more of the applied electrical energy into airflow 17 because it eliminates the losses of the prior art gearbox systems and is significantly 18 more efficient than the prior art gearbox systems.
19 A common prior art technique employed by many operators of cooling towers is to increase water flow into the cooling towers in order to improve condenser 21 performance. FIG. 17 shows a graph of approximated condenser performance.
22 However, the added stress of the increased water flow causes damage to the cooling 23 tower components and actually reduces cooling performance of the tower (L/G ratio). In 24 some cases, it can lead to catastrophic failure such as the collapse of a cooling tower.
However, with the variable process control system of the present invention, increasing 26 water flow is totally unnecessary because the cooling tower design parameters are 27 programmed into both DAQ device 200 and industrial computer 300.
Specifically, in the 1 variable process control system of the present invention, the cooling tower pumps and 2 auxiliary systems are networked with the fans to provide additional control, supervision 3 and monitoring to prevent flooding of the tower and dangerous off-performance 4 operation. In such an embodiment, the pumps are hardwired to DAQ device 200 so that DAQ device 200 controls the operation of the fan, motor and pumps. In such an 6 embodiment, pump-water volume is monitored as a way to prevent the collapse of the 7 tower under the weight of the water. Such monitoring and operation of the pumps will 8 improve part-load cooling performance of the tower as the L/G ratio is maximized for all 9 load and environmental conditions. Such monitoring and operation will also prevent flooding and further reduce energy consumption. The flow rate through the pumps is a ii function of process demand or the process of a component, such as the condenser 12 process. In a preferred embodiment, the variable process control system of the present 13 invention uses variable speed pumps. In an alternate embodiment, variable frequency 14 drive devices, similar to VFD device 22, are used to control the variable speed pumps in order to further improve part-load performance. In a further embodiment, the cooling 16 tower variable speed pumps are driven by permanent magnet motors that have the 17 same or similar characteristics as motor 20.
18 Thus, the variable process control system of the present invention operates the 19 fan at a constant speed and varies the speed of the fan to maintain a constant basin temperature as the environmental and process demand conditions change. The 21 variable process control system of the present invention uses current wet-bulb 22 temperature and environmental stress and past process demand and past 23 environmental stress to anticipate changes in fan speed, and accordingly ramp fan 1 speed up or ramp fan speed down in accordance with a sine wave (see FIG.
9) in order 2 to meet cooling demand. This important characteristic and feature saves energy with 3 relatively smaller and less frequent changes in fan speed. The variable process control 4 system varies the speed of the fan to maintain a constant basin temperature as environmental stress and process demands change and maintains pre-defined heat 6 exchanger and turbine back-pressure set-points in the industrial process in order to 7 maintain turbine back-pressure and avoid heat exchanger fouling. The variable process 8 control system also varies the speed of the fan and the speed of the variable speed 9 pumps to maintain a constant basin temperature as environmental stress and process demands change and maintains pre-defined heat exchanger and turbine back-pressure 11 set-points in the industrial process in order to maintain turbine back-pressure and avoid 12 heat exchanger fouling. The variable process control system of the present invention 13 can also vary the speed of the fan to maintain a constant basin temperature as 14 environmental stress and process conditions change and maintain pre-defined heat exchanger and turbine back-pressure set-points in the industrial process in order to 16 maintain turbine back-pressure and avoid heat exchanger fouling and prevent freezing 17 of the cooling tower by either reducing fan speed or operating the fan in reverse. The 18 variable process control system of the present invention also can vary the speed of the 19 fan to change basin temperature as environmental stress and process conditions change and maintain pre-defined heat exchanger and turbine back-pressure set-points 21 in the industrial process in order to maintain turbine back-pressure and avoid heat 22 exchanger fouling AND prevent freezing of the cooling tower by either reducing fan 23 speed or operating the fan in reverse. The variable process control system of the 1 present invention can also vary the speed of the fan and the speed of the variable 2 speed pumps to change the basin temperature as environmental stress and process 3 conditions change and maintain turbine back-pressure and avoid heat exchanger 4 fouling and prevent freezing of the cooling tower by either reducing fan speed or operating the fan in reverse.
6 Referring to FIG. 26, there is shown a schematic diagram of the variable process 7 control system and motor 20 of the present invention used with a wet-cooling tower that 8 is part of an industrial process. In this embodiment, the variable process control system 9 includes a plurality of variable speed pumps. In this embodiment, motor 20 is configured as the load bearing permanent magnet motor that was discussed in the ii foregoing discussion. Each variable speed pump comprises a load bearing permanent 12 magnet motor that has the same operational characteristics as the permanent magnet 13 motor that was discussed in the foregoing description. Thus, each variable speed pump 14 comprises a permanent magnet motor that has the same operational characteristics as motor 20. Wet-cooling tower 1700 comprises tower structure 1702, fan deck 1704, fan 16 stack 1706 and collection basin 1708. Cooling tower 1700 includes fan 1710 and 17 permanent magnet motor 20 which drives fan 1710. Fan 1710 has the same structure 18 and function as fan 12 which was described in the foregoing description.
Cooling tower 19 1700 includes inlet for receiving make-up water 1712. The portion of cooling tower 1700 that contains the fill material, which is well known in the art, is not shown in FIG.
21 26 in order to simplify the drawing. Collection basin 1708 collects water cooled by fan 22 1710. Variable speed pumps pump the cooled water from collection basin 1708, to 23 condenser 1714, and then to process 1716 wherein the cooled water is used in an 1 industrial process. It is to be understood that condenser 1714 is being used as an 2 example and a similar device, such as a heat exchanger, can be used as well. The 3 condenser temperature set-point is typically set by the operators through the Distributed 4 Control System 315 (see FIG. 3) via signal 1717. The industrial process may be petroleum refining, turbine operation, crude cracker, etc. The variable speed pumps 6 also pump the heated water from process 1716 back to condenser 1714 and then back 7 to cooling tower 1700 wherein the heated water is cooled by fan 1710.
Cooled water 8 exiting collection basin 1708 is pumped by variable speed pump 1722 to condenser 9 1714. Variable speed pump 1722 further includes an instrumentation module which outputs pump status data signals 1726 that represent the flow rate, pressure and 11 temperature of water flowing through variable speed pump 1722 and into condenser 12 1714. Data signals 1726 are inputted into DAQ device 200. This feature will be 13 discussed in the ensuing description. Water exiting condenser 1714 is pumped to 14 process 1716 by variable speed pump 1730. Variable speed pump 1730 includes an instrumentation module that outputs pump status data signals 1734 that represent the 16 flow rate, pressure and temperature of water flowing through variable speed pump 17 1730. Water leaving process 1716 is pumped back to condenser by 1714 by variable 18 speed pump 1738. Variable speed pump 1738 includes an instrumentation module 19 which outputs pump status data signals 1742 that represent the flow rate, pressure and temperature of water flowing through variable speed pump 1738. The water exiting 21 condenser 1714 is pumped back to cooling tower 1700 by variable speed pump 1752.
22 Variable speed pump 1752 further includes an instrumentation module that outputs 23 pump status data signals 1756 that represent the flow rate, pressure and temperature of 1 water flowing through variable speed pump 1752.
2 VFD device 22 comprises a plurality of Variable Frequency Devices.
Specifically, 3 VFD device 22 comprises VFD devices 23A, 23B, 23C, 23D and 23E. VFD
device 23A
4 outputs power over power cable 107. Power cables 107 and 105 are connected to junction box 106. Power cable 105 delivers the power signals to motor 20.
Power 6 cables 105 and 107 and junction box 106 were discussed in the foregoing description.
7 VFD device 23B outputs power signal 1724 for controlling the permanent magnet motor 8 of the variable speed pump 1722. VFD device 23C outputs power signal 1732 for 9 controlling the permanent magnet motor of the variable speed pump 1730.
VFD device 23D outputs power signal 1740 for controlling the permanent magnet motor of the ii variable speed pump 1738. VFD device 23E outputs power signal 1754 for controlling 12 the permanent magnet motor of the variable speed pump 1752. DAQ device 200 is in 13 electronic signal communication with VFD devices 23A, 23B, 23C, 23D and 23E. DAQ
14 device 200 is programmed to control each VFD device 23A, 23B, 23C, 23D
and 23E
individually and independently. All variable speed pump output data signals 1726, 16 1734, 1742 and 1756 from the variable speed pumps 1722, 1730, 1738 and 1752, 17 respectively, are inputted into DAQ device 200. DAQ device 200 processes these 18 signals to determine the process load and thermal load. DAQ device 200 determines 19 the thermal load by calculating the differences between the temperature of the water leaving the collection basin and the temperature of the water returning to the cooling 21 tower. DAQ device 200 determines process demand by processing the flow-rates and 22 pressure at the variable speed pumps. Once DAQ device 200 determines the thermal 23 load and process load, it determines whether the rotational speed of the fan 1710 is 1 sufficient to meet the process load. If the current rotational speed of the fan is not 2 sufficient, DAQ device 200 develops a fan speed curve that will meet the thermal 3 demand and process demand. As described in the foregoing description, DAQ
device 4 200 uses Cooling Tower Thermal Capacity, current thermal demand, current process demand, current environmental stress, and historical data, such as historic process and 6 thermal demand and historic environmental stress to generate a fan speed curve.
7 As shown in FIG. 26, DAQ device 200 also receives the temperature and 8 vibration sensor signals that were discussed in the foregoing description. Typically, the 9 basin temperature set-point is based on the condenser temperature set-point which is usually set by the plant operators. DAQ device 200 determines if the collection basin 11 temperature meets the basin temperature set-point. If the collection basin temperature 12 is above or below the basin temperature set-point, then DAQ device 200 adjusts the 13 rotational speed of motor 20 in accordance with a revised or updated fan speed curve.
14 Therefore, DAQ device 200 processes all sensor signals and data signals from variable speed pumps 1722, 1730, 1738 and 1752. DAQ device 200 is programmed to utilize 16 the processed signals to determine if the speed of the variable speed pumps should be 17 adjusted in order to increase cooling capacity for increased process load, adjust the flow 18 rate of water into the tower, prevent condenser fouling, maintain vacuum back-pressure, 19 or adjust the flow-rate and pressure at the pumps for plant-part load conditions in order to conserve energy. If speed adjustment of the variable speed pumps is required, DAQ
21 device 200 generates control signals that are routed over data bus 202 for input to VFD
22 devices 23B, 23C, 23D and 23E. In response, these VFD devices 23B, 23C, 23D and 23 23E generate power signals 1724, 1732, 1740 and 1754, respectively, for controlling the 1 permanent magnet motors of variable speed pumps 1722, 1730, 1738 and 1752, 2 respectively. DAQ device 200 controls each VFD devices 23A, 23B, 23C, 23D
and 23E
3 independently. Thus, DAQ device 200 can increase the speed of one variable speed 4 pump while simultaneously decreasing the speed of another variable speed pump and adjusting the speed of the fan 1710.
6 In an alternate embodiment of the invention, all variable speed pump output data 7 signals 1726, 1734, 1742 and 1756 are not inputted into DAQ device 200 but instead, 8 are inputted into industrial computer 300 (see FIG. 3) which processes the pump output 9 data signals and then outputs pump control signals directly to the VFD
devices 23B, 23C, 23D and 23E.
11 Each instrumentation module of each variable speed pump includes sensors for 12 measuring motor and pump vibrations and temperatures. The signals outputted by 13 these sensors are inputted to DAQ device 200 for processing.
14 It is to be understood that instrumentation of than the aforesaid instrumentation modules may be used to provide the pump status signals. The electrical power source 16 for powering all electrical components and instruments shown in FIG. 26 is not shown in 17 order to simplify the drawing. Furthermore, all power and signal junction boxes are not 18 shown in order to simplify the drawing.
19 Furthermore, the DAQ device 200 and industrial computer 300 enable the health monitoring of Cooling Tower Thermal Capacity, energy consumption and cooling tower 21 operation as a way to manage energy and thereby further enhance cooling 22 performance, troubleshooting and planning for additional upgrades and modifications.
23 The Federal Clean Air Act and subsequent legislation will require monitoring of 1 emissions from cooling towers of all types (Wet Cooling, Air and HVAC).
Air and 2 hazardous gas monitors can be integrated into the motor housing 21 as Line 3 Replaceable Units to sense leaks in the system. The Line Replaceable Units (LRU) are 4 mounted and sealed into the motor in a manner similar to the (LRU) vibration sensors described in the foregoing description. The LRUs will use power and data 6 communication resources available to other components of the variable process control 7 system. Hazardous gas monitors can also be located at various locations in the cooling 8 tower fan stack and air-flow stream. Such monitors can be electronically integrated 9 with DAQ device 200. The monitors provide improved safety with 100%
monitoring of dangerous gases and also provide the capability to trace the source of the gas (e.g.
ii leaking condenser, heat exchanger, etc.). Such a feature can prevent catastrophic 12 events.
13 In response to the data provided by the sensors, DAQ device 200 generates 14 appropriate signals to control operation of motor 20, and hence fan assembly 12. Thus, the variable process control system of the present invention employs feedback control 16 of motor 20 and monitors all operation and performance data in real-time. As a result, 17 the operation of motor 20 and fan assembly 12 will vary in response to changes in 18 operating conditions, process demand, environmental conditions and the condition of 19 subsystem components. The continuous monitoring feature provide by the feedback loops of the variable process control system of the present invention, shown in FIG. 3, is 21 critical to efficient operation of the cooling tower and the prevention of failure of and 22 damage to the cooling tower and the components of the system of the present 23 invention. As a result of continuously monitoring the parameters of motor 20 that 1 directly relate to the tower airflow, operating relationships can be determined and 2 monitored for each particular cooling tower design in order to monitor motor health, 3 cooling tower health, Cooling Tower Thermal Capacity, provide supervision, trigger 4 inspections and trigger maintenance actions. For example, in the system of the present invention, the horsepower (HP) of motor 20 is related to airflow across fan 12. Thus, if 6 the fill material of the tower is clogged, the airflow will be reduced.
This means that 7 motor 20 and fan assembly 12 must operate longer and under greater strain in order to 8 attain the desired basin temperature. The temperature within the interior of motor 9 casing 21 and stator 32 increases and the motor RPM starts to decrease.
The aforementioned sensors measure all of these operating conditions and provide DAQ
ii device 200 with data that represents these operating conditions. The feedback loops 12 continuously monitor system resonant vibrations that occur and vary over time and 13 initiate operational changes in response to the resonant vibrations thereby providing 14 adaptive vibration control. If resonant vibrations occur at a certain motor speed, then the feedback loops cause that particular motor speed (i.e. RPM) to be locked out.
16 When a motor speed is locked out, it means that the motor 20 will not be operated at 17 that particular speed. If the vibration signature is relatively high, which may indicate 18 changes in the fan blade structure, ice build-up or a potential catastrophic blade failure, 19 the feedback loops will cause the system to shut down (i.e. shut down motor 20). If a vibration signature corresponds to stored data representing icing conditions (i.e.
21 temperature, wind and fan speed), then DAQ device 200 will automatically initiate the 22 De-Icing Mode of operation. Thus, the feedback loops, sensors, pump status signals, 23 and DAQ device 200 cooperate to:

1 a) measure vibrations at the bearings of motor 20;
2 b) measure temperature at the stator of motor 20;
3 measure temperature within motor casing 21;
4 d) measure environmental temperatures near motor 20 and fan assembly 12;
determine process demand;
6 f) measure the temperature of the water in the cooling tower collection 7 basin;
8 identify high vibrations which are the characteristics of "blade-out" or 9 equivalent and immediately decelerate the fan to zero (0) RPM and hold the fan from windmilling, and immediately alert the operators using the 11 known alert systems (e.g. email, text or DCS alert);
12 h) lock out particular motor speed (or speeds) that create resonance;
13 identify icing conditions and automatically initiate the De-Icing Mode of 14 operation and alert operators and personnel via e-mail, text or DCS alert;
and 16 j) route the basin-water temperature data to other portions of the industrial 17 process so as to provide real-time cooling feedback information that can 18 be used to make other adjustments in the overall industrial process.
19 In a preferred embodiment, the variable process control system of the present invention further comprises at least one on-sight camera 480 that is located at a 21 predetermined location. Camera 480 is in electrical signal communication with 22 communication data junction box 111 and outputs a video signal that is fed to DAQ
23 device 200. The video signals are then routed to display screens that are being 1 monitored by operations personnel. In a preferred embodiment, the video signals are 2 routed to industrial computer 300 and host server 310. The on-sight camera 480 3 monitors certain locations of the cooling tower to ensure authorized operation. For 4 example, the camera can be positioned to monitor motor 20, the cooling tower, the fan, etc. for unauthorized entry of persons, deformation of or damage to system 6 components, or to confirm certain conditions such as icing. In a preferred embodiment, 7 there is a plurality of on-sight cameras.
8 Industrial computer 300 is in data communication with data base 301 for storing 9 (1) historical data, (2) operational characteristics of subsystems and components, and (3) actual, real-time performance and environmental data. Industrial computer 300 is 11 programmed to use this data to optimize energy utilization by motor 20 and other 12 system components, generate trends, predict performance, predict maintenance, and 13 monitor the operational costs and efficiency of the system of the present invention.
14 Industrial computer 300 uses historical data, as a function of date and time, wherein such historical data includes but is not limited to (1) weather data such as dry bulb 16 temperature, wet bulb temperature, wind speed and direction, and barometric 17 temperature, (2) cooling tower water inlet temperature from the process (e.g. cracking 18 crude), (3) cooling tower water outlet temperature return to process, (4) fan speed, (5) 19 cooling tower plenum pressure at fan inlet, (6) vibration at bearings, (7) all motor temperatures, (8) cooling tower water flow rate and pump flow-rates, (9) basin 21 temperature, (10) process demand for particular months, seasons and times of day, 22 (11) variations in process demand for different products, e.g. light crude, heavy crude, 23 etc., (12) previous maintenance events, and (13) library of vibration signatures, (14) 1 cooling tower design, (15) fan map, (16) fan pitch and (17) Cooling Tower Thermal 2 Capacity.
3 Industrial computer 300 also stores the operational characteristics of subsystems 4 or components which include (1) fan pitch and balancing at commissioning, (2) known motor characteristics at commissioning such as current, voltage and RPM
ratings, 6 typical performance curves, and effects of temperature variations on motor 7 performance, (3) variation in performance of components or subsystem over time or 8 between maintenance events, (4) known operating characteristics of variable frequency 9 drive (VFD), (5) operating characteristics of accelerometers including accuracy and performance over temperature range, and (6) cooling tower performance curves and (7) ii fan speed curve. Actual real-time performance and environmental data are measured 12 by the sensors of the system of the present invention and include:
13 1) weather, temperature, humidity, wind speed and wind direction;
14 2) temperature readings of motor interior, motor casing, basin liquids, air flow generated by fan, variable frequency drive, and data acquisition device;
16 3) motor bearing accelerometer output signals representing particular vibrations 17 (to determine fan pitch, fan balance and fan integrity);
18 4) plenum pressure at fan inlet;
19 5) pump flow-rates which indicate real-time variations in process demand;
6) motor current (amp) draw and motor voltage;
21 7) motor RPM (fan speed);
22 8) motor torque (fan torque);
23 9) motor power factor;

1 10) motor horsepower, motor power consumption and efficiency;
2 11) exception reporting (trips and alarms);
3 12) system energy consumption; and 4 13) instrumentation health.
Industrial computer 300 processes the actual real-time performance and 6 environmental data and then correlates such data to the stored historical data and the 7 data representing the operational characteristics of subsystems and components in 8 order to perform the following tasks: (1) recognize new performance trends, (2) 9 determine deviation from previous trends and design curves and related operating tolerance band, (3) determine system power consumption and related energy expense, ii (4) determine system efficiency, (5) development of proactive and predictive 12 maintenance events, (6) provide information as to how maintenance intervals can be 13 maximized, (7) generate new fan speed curves for particular scenarios, and (8) highlight 14 areas wherein management and operation can be improved. VFD device 22 provides DAQ device 200 with data signals representing motor speed, motor current, motor 16 torque, and power factor. DAQ device 200 provides this data to industrial computer 17 300. As described in the foregoing description, industrial computer 300 is programmed 18 with design fan map data and cooling tower thermal design data. Thus, for a given 19 thermal load (temperature of water in from process, temperature of water out from process and flow, etc.) and a given day (dry bulb temp, wet bulb temp, barometric 21 pressure, wind speed and direction, etc.), the present invention predicts design fan 22 speed from the tower performance curve and the fan map and then compares the 23 design fan speed to operating performance. The design of each tower is unique and 1 -- therefore the programming of each tower is unique. The programming of all towers 2 -- includes the operational characteristic that a tower clogged with fill would require the 3 -- motor to run faster and longer and would be captured by trending. Fan inlet pressure 4 -- sensors are in electronic signal communication with DAQ device 200 and provide data -- representing airflow. Since industrial computer 300 determines operating tolerances 6 -- based on trending data, the operation of the fan 12 at higher speeds may trigger an 7 -- inspection. This is totally contrary to prior art fan drive systems wherein the operators 8 -- do not know when there are deviations in operational performance when tower fill 9 -- becomes clogged.
Industrial computer 300 is programmed to compare the signals of the vibration 11 -- sensors 400, 402, 404 and 406 on motor the bearing housings 50 and 52 as a way to 12 -- filter environmental noise. In a preferred embodiment, industrial computer 300 is 13 -- programmed so that certain vibration frequencies are maintained or held for a 14 -- predetermined amount of time before any reactive measures are taken.
Certain -- vibration frequencies indicate different failure modes and require a corresponding 16 -- reaction measure. The consistent and tight banding of the vibration signature of motor 17 -- 20 allows for greater control and supervision because changes in the system of the 18 -- present invention can be isolated and analyzed immediately thereby allowing for 19 -- corrective action. Isolated vibration spikes in the system of the present invention can be -- analyzed instantaneously for amplitude, duration, etc. Opposing motor bearing 21 -- signatures can be compared to minimize and eliminate trips due to environmental 22 -- vibrations without impacting safety and operation (false trip). As described in the 23 -- foregoing description, industrial computer 300 is also programmed with operational 1 characteristics of the wet-cooling tower and ACHE. For example, industrial computer 2 300 has data stored therein which represents the aerodynamic characteristics of the fill 3 material in the cooling tower. The processor of industrial computer 300 implements 4 algorithms that generate compensation factors based on these aerodynamic characteristics. These compensation factors are programmed into the operation 6 software for each particular cooling tower. Thus, the positive or negative aerodynamic 7 characteristics of the fill material of a particular wet-cooling tower or ACHE are used in 8 programming the operation of each wet-cooling tower or ACHE. As described in the 9 foregoing description, industrial computer 300 is programmed with the historical weather data for the particular geographical location in which the wet-cooling tower or ACHE is ii located. Industrial computer 300 is also programmed with historical demand trend 12 which provides information that is used in predicting high-process demand and low-13 process demand periods. Since industrial computer 300 and DAQ device 200 are 14 programmed with the cooling tower thermal design data that is unique to each tower including the fan map, each cooling tower can be designed to have its own unique set of 16 logic depending on its geographical location, design (e.g. counter-flow, cross flow, 17 ACHE, HVAC) and service (e.g. power plant, refinery, commercial cooling, etc.). When 18 these characteristics are programmed into industrial computer 300, these 19 characteristics are combined with sufficient operational data and trending data to establish an operational curve tolerance band for that particular cooling tower. This 21 enables cooling tower operators to predict demand based upon historical operational 22 characteristics and optimize the fan for energy savings by using subtle speed changes 23 as opposed to dramatic speed changes to save energy.

1 A significant feature of the present invention is that the air flow through the 2 cooling tower is controlled via the variable speed fan to meet thermal demand and 3 optimize energy efficiency of the system. DAQ device 200 generates motor-speed 4 control signals that are based on several factors including cooling tower basin temperature, historical trending of weather conditions, process cooling demand, time of 6 day, current weather conditions such as temperature and relative humidity, cooling 7 tower velocity requirements, prevention of icing of the tower by reducing fan speed, and 8 de-icing of the tower using reverse rotation of the fan. Thus, the system of the present 9 invention can anticipate cooling demand and schedule the fan (or fans) to optimize energy savings (ramp up or ramp down) while meeting thermal demand. The system of ii the present invention is adaptive and thus learns the cooling demand by historical 12 trending (as a function of date and time).
13 The speed of the fan or fans may be increased or decreased as a result of any 14 one of several factors. For example, the speed of the fan or fans may be decreased or increased depending upon signals provided by the basin water temperature sensor. In 16 another example, the speed of the fan or fans may be increased or decreased as a 17 result of variable process demand wherein the operator or programmable Distributed 18 Control System (DCS) 315 generates a signal indicating process-specific cooling needs 19 such as the need for more cooling to maintain or lower turbine backpressure. In a further example, the speed of the fan or fans may be increased or decreased by raising 21 the basin temperature if the plant is operating at part-load production.
Fan speed can 22 also be raised in "compensation mode" if a cell is lost in a multiple-cell tower in order to 23 overcome the cooling loss. Since motor 20 provides more torque than a comparable 1 prior art induction motor, motor 20 can operate with increased fan pitch providing 2 required design airflow at slower speeds. Since most 100% speed applications operate 3 at the maximum fan speed of 12,000 fpm to 14,000 fpm maximum tip speed depending 4 upon the fan design, the lower speeds of motor 20 provide an airflow buffer that can be used for hot day production, compensation mode and future cooling performance.
6 A particular geographical location may have very hot summers and very cold 7 winters. In such a case, the variable process control system operates the fan in the 8 " hot-day" mode of operation on very hot summer days in order to meet the maximum 9 thermal load at 100%. When the maximum thermal load diminishes, the speed of the fan is then optimized at lower fan speeds for energy optimization. The fan will operate 11 in this energy optimization mode during the cooler months in order to optimize energy 12 consumption, which may include turning fan cells off. Since the torque of motor 20 is 13 constant, the shifting of fan speed between maximum operation and energy optimization 14 is without regard to fan pitch. The constant, high-torque characteristics of motor 20 allow the fan to be re-tasked for (true) variable speed duty. Thus, the variable process 16 control system of the present invention operates in a manner totally opposite to that of 17 prior art fan drive systems wherein an induction motor drives the fan at 100% speed, 18 typically between 12,000 and 14,000 ft/min tip speed, and wherein the fan remains at 19 constant speed and its pitch is limited by the torque limitations of the induction motor. In order to provide the required torque, the size of the prior art induction motor would have 21 to be significantly increased, but this would dramatically increase the weight of the 22 motor. On the other hand, in the present invention, permanent magnet motor 20 is able 23 to drive the fan at slower speeds with increased fan pitch without exceeding the fan tip 1 speed limitation of 12,000 feet/minute. Slower fan speed also allows for quieter 2 operation since fan noise is a direct function of speed. Motor 20 allows 100% design air 3 flow to be set below the maximum fan tip speed. This feature allows for a design buffer 4 to be built into the variable process control system of the present invention to allow for additional cooling capacity in emergency situations such as the compensation mode (for 6 multi-cell systems) or extremely hot days or for increased process demand such as 7 cracking heavier crude. The constant torque of motor 20 also means that part-load 8 operation is possible without the limitations and drawbacks of prior art fan drive systems 9 that use a gearbox and induction motor. In such prior art systems, part-load torque may not be sufficient to return the fan to 100% speed and would typically require a larger ii induction motor with increased part-load torque.
12 Motor 20 converts relatively more "amperes to air" than prior art gearbox 13 systems. Specifically, during actual comparison testing of a cooling system using motor 14 20 and a cooling system using a prior art gearbox system, motor 20 is at least 10%
more efficient than prior art gearbox systems. During testing, at 100% fan speed and 16 design pitch, a power-sight meter indicated the prior art gearbox system demanded 50 17 kW whereas motor 20 demanded 45 kW. Almost all existing towers are cooling limited.
18 Since motor 20 is a drop-in replacement for prior art gearboxes, motor 20 will have an 19 immediate impact on cooling performance and production.
The system and method of the present invention is applicable to multi-cell cooling 21 apparatuses. For example, a wet-cooling tower may comprise a plurality of cells 22 wherein each cell has a fan, fan stack, etc. Similarly, a multi-cell cooling apparatus may 23 also comprise a plurality of ACHEs, HVACs or chillers (wet or dry, regardless of 1 mounting arrangement). Referring to FIGS. 15A, 15B and 15C, there is multi-cell 2 cooling apparatus 600 which utilizes the variable process control system of the present 3 invention. Multi-cell cooling apparatus 600 comprises a plurality of cells 602. Each cell 4 602 comprises fan assembly 12 and fan stack 14. Fan assembly 12 operates within fan stack 14 as described in the foregoing description. Each cell 602 further comprises load 6 bearing permanent magnet motor 20. In this embodiment, the system of the present 7 invention includes Motor Control Center (MCC) 630. A Motor Control Center (MCC) 8 typically serves more than motor or fan cell. The Motor Control Center is typically 9 located outside of the Class One, Division Two area on the ground, at least ten feet from the cooling tower. The Motor Control Center is in a walk-in structure that houses ii VFD device 22, DAQ device 200, industrial computer 300, power electronics and 12 Switchgear. The Motor Control Center is air-conditioned to cool the electronics. The 13 Motor Control Center is typically a walk-in metal building that houses the DAQ device, 14 the Variable Frequency Drives, the industrial computer 300 and the power electronics.
MCC 630 comprises a plurality of Variable Frequency Drive (VFD) devices 650.
Each 16 VFD device 650 functions in the same manner as VFD device 22 described in the 17 forgoing description. Each VFD device 650 controls a corresponding motor 20. Thus, 18 each motor 20 is controlled individually and independent of the other motors 20 in the 19 multi-cell cooling apparatus 600. MCC 630 further comprises a single Data Acquisition (DAQ) device 660 which is in data signal communication with all of the VFD
devices 650 21 and all sensors (e.g. motor, temperature, vibration, pump-flow, etc.) in each cell. These 22 sensors were previously described in the foregoing description. DAQ
device 660 23 controls the VFD devices 650 in the same manner as DAQ device 200 controls VFD

1 device 22 which was previously described in the foregoing description.
DAQ device 660 2 is also in data signal communication with industrial computer 300 via data bus 670.
3 Industrial computer 300 is in data signal communication with database 301. Both 4 industrial computer 300 and database 301 were previously described in the foregoing description. As shown in FIG. 15A, there are a plurality of communication data junction 6 boxes 634 which receive the signals outputted by the sensors (e.g.
temperature, 7 pressure, vibration). Each communication data junction box 634 is in data signal 8 communication with DAQ device 660. Each communication data junction box 634 has 9 the same function and purpose as communication data junction box 111 described in the foregoing description. The power signals outputted by the VFD devices 650 are ii routed to motor disconnect junction boxes 636 which are located outside of fan stack 12 14. Each motor disconnect junction box 636 has the same configuration, purpose and 13 function as motor disconnect junction box 106 previously described in the foregoing 14 description. Since there is a dedicated VFD device 650 for each motor 20, each cell 602 is operated independently from the other cells 602. Thus, this embodiment of the 16 present invention is configured to provide individual and autonomous control of each 17 cell 602. This means that DAQ device 660 can operate each fan at different variable 18 speeds at part-load based on process demand, demand trend, air-flow characteristics of 19 each tower (or fill material) and environmental stress. Such operation optimizes energy savings while meeting variable thermal loading. Such a configuration improves energy 21 efficiency and cooling performance. For example, if all fans are operating at minimum 22 speed, typically 80%, and process demand is low, DAQ device 660 is programmed to 23 output signals to one or more VFD devices 650 to shut off the corresponding fans 12.

1 DAQ device 660 implements a compensation mode of operation if one of the cells 602 2 is not capable of maximum operation, or malfunctions or is taken off line. Specifically, if 3 one cell 602 is lost through malfunction or damage or taken off line, DAQ
device 660 4 controls the remaining cells 602 so these cells compensate for the loss of cooling resulting from the loss of that cell. End wall cells are not as effective as cells in the 6 middle of the tower and therefore, the end wall cells may be shut off earlier in hot 7 weather or may need to run longer in cold weather. In accordance with the invention, 8 the fan speed of each cell 602 increases and decreases throughout the course of a 9 cooling day in a pattern generally similar to a sine wave as shown in FIG. 9. DAQ
device 660 can be programmed so that when the basin temperature set-point is not met ii (in the case of a wet-cooling tower), DAQ device 660 issues signals to the VFD devices 12 650 to increase fan speed based on a predictive schedule of speed increments based 13 on (a) part-load based on process demand, (b) demand trend, (c) air flow characteristics 14 of each tower (or fill material) and (d) environmental stress without returning fan speed to 100%. This operational scheme reduces energy consumption by the cell and 16 preserves the operational life of the equipment. This is contrary to prior art reactive 17 cooling schedules which quickly increase the fans to 100% fan speed if the basin 18 temperature set-point is not met.
19 The system and method of the present invention provides infinite variable fan speed based on thermal load, process demand, historical trending, energy optimization 21 schedules, and environmental conditions (e.g. weather, geographical location, time of 22 day, time of year, etc.). The present invention provides supervisory control based on 23 continuous monitoring of vibrations, temperature, pump flow rate and motor speed. The 1 present invention uses historical trending data to execute current fan operation and 2 predicting future fan operation and maintenance. The system provides automatic de-3 icing of the fan without input from the operator.
4 De-icing cooling towers using load bearing permanent magnet motor 20 is relatively easier, safer and less expensive than de-icing cooling towers using prior art 6 gearbox fan drive systems. The capability of motor 20 to operate the fans at slower 7 speeds in colder weather reduces icing. Motor 20 has no restrictions or limitations in 8 reverse rotation and can therefore provide the heat retention required to de-ice a tower 9 in winter. DAQ device 200 is configured to program the operation of motor 20 to implement de-icing based on outside temperature, wind speed and direction, wet bulb 11 temperature, and cooling tower inlet/outlet and flow rate. All parameters are used to 12 develop a program of operation that is tailored made for the particular and unique 13 characteristics of each cooling tower, the cooling tower's location and environment 14 stress.
Motor 20 provides constant high torque thereby allowing the fan to operate at a 16 relatively slower speed with greater pitch to satisfy required air-flow while reducing 17 acoustic noise (acoustic noise is a function of fan speed) with additional airflow built into 18 the system for other functions. This is not possible with prior art fan drive systems that 19 use a single-speed gear-box and induction motor that drives the fan at 100% speed at the maximum tower thermal condition for 100% of the time. Unlike prior art fan drive 21 systems, motor 20 is capable of infinite variable speed in both directions. Motor 20 is 22 configured to provide infinite variable speed up to 100% speed with constant torque but 23 without the duration restrictions of prior art fan drive systems that relate to induction 1 motor torque at part-load, drive train resonance, torque load relative to pitch, and 2 induction motor cooling restrictions.
3 The infinite variable speed of motor 20 in both directions allows the fan to match 4 the thermal loading to the environmental stress. This means more air for hot-day cooling and less air to reduce tower icing. The infinite variable speed in reverse without 6 duration limitations enables de-icing of the tower. Motor 20 provides high, constant 7 torque in both directions and high, constant torque adjustment which allows for greater 8 fan pitch at slower fan speeds. These important features allow for a built-in fan-speed 9 buffer for emergency power and greater variation in diurnal environments and seasonal changes without re-pitching the fan. Thus, the infinite variable speed adjustment aspect ii of the present invention allows for built-in cooling expansion (greater flow) and built-in 12 expansion without changing a motor and gear box as required in prior art fan drive 13 systems. The present invention provides unrestricted variable speed service in either 14 direction to meet ever changing environmental stress and process demand that results in improved cooling, safety and reduced overhead. All parameters are used to develop 16 a unique programmed, operation for each cooling tower design, the cooling tower's 17 geographical location and the corresponding environmental stress. DAQ
device 200 18 operates motor 20 (and thus fan 12) in a part-load mode of operation that provides 19 cooling with energy optimization and then automatically shifts operation to a full-load mode that provides relatively more variable process control which is required to crack 21 heavier crude. Once the process demand decreases, DAQ device 200 shifts operation 22 of motor 20 back to part-load.
23 Due to the fan hub interface, the motor shaft 24 is relatively large.
The bearings 1 of motor 20 are relatively large in order to accomodate the relatively large motor shaft 2 24. Combined with the slow speed of the application, the bearing system is only 20%
3 loaded, thereby providing an L10 life of 875,000 hours. The 20% loading and unique 4 bearing design of motor 20 provides high fidelity of vibration signatures and consistent narrow vibration band signatures well below the current trip setting values.
As a result, 6 there is improved monitoring via historical trending and improved health monitoring via 7 vibration signatures beyond the operating tolerance. The bearing system of motor 20 8 enables motor 20 to rotate fans of different diameters and at all speeds and torques in 9 both directions and is specifically designed to bear radial and yaw loads from the fan, axial loads in both directions from fan thrust and fan dead weight, and reverse loads ii which depend upon the mounting orientation of motor 20, e.g. motor shaft up, motor 12 shaft down, motor shaft in horizontal orientation, or combinations thereof.
13 The variable process control system of the present invention determines Cooling 14 Tower Thermal Capacity so as to enable operators to identify proactive service, maintenance and cooling improvements and expansions. The present invention 16 provides the ability to monitor, control, supervise and automate the cooling tower 17 subsystems so as to manage performance and improve safety and longevity of these 18 subsystems. The system of the present invention is integrated directly into an existing 19 refinery Distributed Control System (DCS) so as to allow operators to monitor, modify, update and override the variable process control system in real time.
Operators can use 21 the plant DCS 315 to send data signals to the variable process control system of the 22 present invention to automatically increase cooling for cracking crude or to prevent 23 auxiliary system fouling or any other process. As shown by the foregoing description, for 1 a given fan performance curve, a cooling tower can be operated to provide maximum 2 cooling as a function of fan pitch and speed. Fan speed can be reduced if basin 3 temperature set-point is met. The present invention provides accurate cooling control 4 with variable speed motor 20 as a function of environmental stress (e.g.
cooling and icing), variable process control (i.e. part load or more cooling for cracking crude, etc.) 6 and product quality such as light end recovery with more air-per-amp for existing 7 installations. The variable process control system of the present invention allows 8 operators to monitor cooling performance in real time thereby providing the opportunity 9 to improve splits and production and identify service and maintenance requirements to maintain cooling performance and production throughput. Furthermore, the data ii acquired by the system of the present invention is utilized to trend cooling performance 12 of the cooling tower which results in predictive maintenance that can be planned before 13 outages occur as opposed to reactive maintenance that results in downtime and loss of 14 production. The unique dual-bearing design of motor 20, the placement of accelerometers, velocity probes and displacement probes on each of these bearings, 16 and the vibration analysis algorithms implemented by industrial computer 300 allow 17 significant improvements in fan vibration monitoring and provides an effective trim 18 balancing system to remove the fan dynamic couple. The trim balance feature removes 19 the fan dynamic couple which reduces structural fatigue on the cooling tower.
The present invention eliminates many components and machinery used in prior 21 art fan drive systems such as gearboxes, shafts and couplings, two-speed motors, 22 gearbox sprag clutches to prevent reverse operation, electric and gerotor lube pumps 23 for gearboxes and vibration cut-off switches. Consequently, the present invention also 1 eliminates the maintenance procedures related to the aforesaid prior art components, 2 e.g. pre-seasonal re-pitching, oil changes and related maintenance. The present 3 invention allows monitoring and automation of the operation of the cooling tower 4 subsystems to enable management of performance and improvement in component longevity. The present invention allows continuous monitoring and management of the 6 permanent magnet motor 20, the fan and the cooling tower itself. The present invention 7 allows for rapid replacement of a prior art fan drive system with motor 20, without 8 specialized craft labor, for mission critical industries minimizing production loss. The 9 system of the present invention provides an autonomous de-icing function to de-ice and/or prevent icing of the cooling tower.
11 The system of the present invention is significantly more reliable than prior art 12 systems because the present invention eliminates many components, corresponding 13 complexities and problems related to prior art systems. For example, prior art 14 gearboxes and corresponding drive trains are not designed for the harsh environment of cooling towers but were initially attractive because of their relatively lower initial cost.
16 However, in the long run, these prior art fan drive systems have resulted in high Life-17 Cycle costs due to continuous maintenance and service expense (e.g. oil changes, 18 shaft alignments, etc.), equipment failure (across-the-line start damage), application of 19 heavy duty components, poor reliability, lost production and high energy consumption.
The data collected by DAQ device 200, which includes motor voltage, current, 21 power factor, horsepower and time is used to calculate energy consumption. In 22 addition, voltage and current instrumentation are applied to the system to measure 23 energy consumption. The energy consumption data can be used in corporate energy 1 management programs to monitor off-performance operation of a cooling tower. The 2 energy consumption data can also be used to identify rebates from energy savings or to 3 apply for utility rebates, or to determine carbon credits based upon energy savings. The 4 system of the present invention also generates timely reports for corporate energy coordinators on a schedule or upon demand. The data provided by DAQ device 200 6 and the post-processing of such data by industrial computer 300 enables cooling 7 performance management of the entire system whether it be a wet-cooling tower, air-8 cooled heat exchanger (ACHE), HVAC systems, chillers, etc. Specifically, the data and 9 reports generated by DAQ device 200 and industrial computer 300 enable operators to monitor energy consumption and cooling performance. The aforesaid data and reports ii also provide information as to predictive maintenance (i.e. when maintenance of cooling 12 tower components will be required) and proactive maintenance (i.e.
maintenance to 13 prevent a possible breakdown). Industrial computer 300 records data pertaining to fan 14 energy consumption and thus, generates fan energy consumption trends.
Industrial computer 300 executes computer programs and algorithms that compare the 16 performance of the cooling tower to the energy consumption of the cooling tower in 17 order to provide a cost analysis of the cooling tower. This is an important feature since 18 an end user spends more money operating a poor performing tower (i.e.
lower flow 19 means more fan energy consumption and production loss) than a tower than is in proper operating condition. Industrial computer 300 implements an algorithm to express 21 the fan energy consumption as a function of the tower performance which can be used 22 in annual energy analysis reports by engineers and energy analysts to determine if the 23 tower is being properly maintained and operated. Energy analysis reports can be used 1 to achieve energy rebates from utilities and for making operational improvement 2 analysis, etc. With respect to large capital asset planning and utilization cost, a relation 3 is derived by the following formula:
4 N= (Cooling Tower Thermal Capacity)/(Cooling Tower Energy Consumption) 6 wherein the quotient "N" represents a relative number that can be used to determine if a 7 cooling tower is operating properly or if it has deteriorated or if it is being incorrectly 8 operated. Deterioration and incorrect operation of the cooling tower can lead to safety 9 issues such as catastrophic failure, poor cooling performance, excessive energy consumption, poor efficiency and reduced production.
11 The present invention provides accurate cooling control with variable speed 12 motor 20 as a function of environmental stress (cooling and icing), variable process 13 control (part load or more cooling for cracking, etc.) and product quality such as light 14 end recovery with more air-per-amp for existing installations. The present invention also provides automatic adjustment of fan speed as a function of cooling demand 16 (process loading), environmental stress and energy efficiency and provides adaptive 17 vibration monitoring of the fan to prevent failure due to fan imbalance and system 18 resonance. The present invention allows the fans to be infinitely pitched due to 19 constant, high torque. The built-in vibration monitoring system provides a simple and cost effective trim balance to eliminate fan dynamic couple and subsequent structural 21 wear and tear. The variable process control system of the present invention reduces 22 maintenance to auxiliary equipment, maintains proper turbine back pressure and 23 prevents fouling of the condensers. Motor 20 provides constant torque that drives the 24 fan at lower speed to achieve design airflow at a greater fan pitch thereby reducing fan 1 noise which typically increases at higher fan speeds (noise is a function of fan speed).
2 The present invention reduces energy consumption and does not contribute to global 3 warming. The high-torque, variable speed, load bearing permanent magnet motor 20 4 expands the operational range of the fan to meet ever changing process load changes and environmental conditions by providing high, constant torque for full fan pitch 6 capability. This enables increased airflow for existing installations, provides unrestricted 7 variable speed for energy savings and reduction of ice formation, and allows reverse 8 operation of the fan for retaining heat in the cooling tower for de-icing.
9 Although the previous description describes how motor 20 and the corresponding system components (e.g. VFD 22, DAQ device 200, etc.) may be used to retrofit an 11 existing cooling tower that used a prior art fan drive system, it is to be understood that 12 the direct-drive system and variable process control system of the present invention can 13 be used in newly constructed cooling towers, regardless of the materials used to 14 construct such new cooling towers, e.g. wood, steel, concrete pier mountings, pultruded fiber-reinforced plastic (FRP) structures, or combinations thereof.
16 In an alternate embodiment of the invention, the load bearing motor 20 is used to 17 drive fans that are supported by a separate, independent structure.
Specifically, in such 18 an embodiment, the axial yaw and most radial loads are supported by the separate, 19 independent structure and the load bearing motor provides torque, speed and some radial loading.
21 Referring to FIG. 27, there is shown another wet cooling tower that utilizes load 22 bearing, direct drive motor 20 and the variable process control system of the present 23 invention. Wet cooling tower 1800 comprises a cooling tower structure 1802 which 1 includes generally vertical walls 1804, 1805, 1806 and a forth, front wall that is not 2 shown, that form a duct. Wet cooling tower 1800 further comprises top structure 1808.
3 Motor 20 is attached to top structure 1808 and is oriented such that motor shaft 24 4 extends downward. Fan 12 is attached to motor shaft 24. Wet cooling tower structure 1800 includes water distribution device 1820, fill material or fill pack 1830 and collection 6 basin 1840. Collection basin 1840 collects fluids 1850 (e.g. water).
Since such cooling 7 tower structures are known in the art, the details of air-flow and water flow are not 8 discussed herein. In an alternate embodiment, motor 20 is attached to top structure 9 1808 and is oriented such that motor shaft 24 extends upward and fan 12 is attached to motor shaft 24. In such an embodiment, fan 12 is above motor 20.
11 Referring to FIG. 28, there is shown a diagram of one type of hybrid cooling 12 tower that utilizes the load bearing motor 20 and the variable process control system of 13 the present invention. Hybrid cooling tower 2000 comprises cooling tower structure 14 2002 which has interior 2003. Cooling tower structure 2002 comprises fan stack 2004 that is positioned at the upper portion of cooling tower structure 2002. Load bearing 16 motor 20 is supported by horizontal member 2006. Fan 12 is connected to shaft 24 of 17 load bearing motor 20. Hybrid cooling tower 2000 further comprises tube bundle or 18 tube network 2010 that is positioned beneath the fan 12. Hot fluid or hot water 2012 19 coming from the process is inputted into tube bundle 2010. Cold water 2014 exits tube bundle 2010. Hybrid cooling tower 2000 further comprises water distribution device 21 2020 and wet tower fill material or fill pack 2030. Fill material 2030 is positioned under 22 water distribution device 2020. Water distribution device 2020 distributes hot fluid or 23 water 2012 over water tower fill material 2030. Hybrid cooling tower 2000 further 1 comprises collection basin 2040 which collects the cooled fluid and outputs cooling 2 water 2050. Cooling water 2050 is returned to the process. Air 2060 is allowed to flow 3 into interior 2003 via air inlet device 2070. Typically, air inlet device 2070 is configured 4 as a shutter device. The rotation of fan 12 creates an air flow, indicated by reference numbers 3000, which flows upward and out through fan stack 2004. In some types of 6 hybrid cooling towers, mist elimination devices are used to eliminate mist carried by the 7 air flow from wet tower fill material 2030.
8 The present invention is also applicable to steel mills and glass processing, as 9 well as any other process wherein the control of cooling water is critical. Temperature control of the water is crucial for cooling the steel and glass product to obtain the correct ii material composition. The capability of the present invention to provide constant basin 12 water temperature is directly applicable to steel mill operation, glass processing and 13 resulting product quality and capacity. The capability of motor 20 and fan 12 to operate 14 in reverse without limitation allows more heat to be retained in the process water on cold days. This would be accomplished by slowing the fan 12 or operating the fan 12 in 16 reverse in order to retain more heat in the tower and thus, more heat in the process 17 water in the basin. The variable process control feature of the system of the present 18 invention can deliver infinite temperature variation on demand to the process as 19 required to support production and improve control and quality of the product.
It is to be understood that the direct-drive fan system of the present invention 21 may be configured with motors or prime drivers other than the permanent magnet motor 22 described in the forgoing description. For example, in one alternate embodiment, 23 permanent magnet motor 20 and the permanent magnet motors in variable speed 1 pumps 1722, 1730, 1738 and 1752 are replaced by synchronous reluctance motors. In 2 such an embodiment, the synchronous reluctance motor that rotates the fan comprises 3 a casing, stator, rotor, shaft, bearing system and sealing system that are designed to 4 support the fan loads (discussed in the foregoing description) with respect to operating temperature, operating speed, orientation and motor design characteristics. In one 6 embodiment, the synchronous reluctance motor that rotates the fan comprises the same 7 bearing configuration as the load bearing permanent magnet motor that was discussed 8 in the foregoing description. Thus, the modified load bearing synchronous reluctance 9 motor would be configured to bear all fan loads whether the fan is rotating in forward, reverse or is at 0.00 RPM and also bear all loads created by external forces exerted on ii the fan, such as relatively strong wind gusts. In such an embodiment, the Variable 12 Process Control system of the present invention controls the synchronous reluctance 13 motors in the same manner as was done for the permanent magnet motors.
14 Motor 20 and the motors of the variable speed pumps 1722, 1730, 1738 and 1752 may be realized by other suitable load bearing motors. For example, the load 16 bearing direct drive system of the present invention may comprise any of the motor 17 types listed below that are designed in accordance with the invention such that the 18 motor comprises a casing, stator, rotor, shaft, bearing system and sealing system that 19 support the fan loads (discussed in the foregoing description) with respect to operating temperature, operating speed, orientation and motor design characteristics.
These 21 motor types include:
22 a) single speed Totally Enclosed Fan Cooled (TEFC) AC induction motor (e.g.
23 asynchronous motor);

1 b) variable speed TEFC AC induction motor;
2 c) inverted rated induction motor with VFD;
3 d) switched reluctance motor;
4 e) brushless DC motor;
f) pancake DC motor;
6 g) synchronous AC motor;
7 h) salient pole interior permanent magnet motor;
8 i) interior permanent magnet motor;
9 j) finned laminated, permanent magnet motor;
k) series-wound motor or universal motor;
ii 1) traction motor;
12 m) series-wound, brushed DC motor; and 13 n) stepper motor.
14 It is to be understood that the casing, stator, rotor, shaft, bearing system and sealing system of the motor may be designed to have different sizes or dimensions in 16 order to provide a desired torque and speed range for a particular fan in a cooling tower 17 or ACHE tower.
18 The present invention may be applied to applications other than cooling towers, 19 air-cooled heat exchangers or hybrid cooling towers. For example, all of the embodiments of the direct-drive system and variable process control system of the 21 present invention may be used in other applications including HVAC, chillers, windmills 22 or wind turbine generators, paper machines, marine propulsion systems, ski-lifts and 23 elevators. The present invention is also applicable to steel mills and glass processing, 1 as well as any other process wherein the control of the temperature and flow of cooling 2 water is critical. Temperature control of the water is crucial for cooling the steel and 3 glass product to obtain the correct material composition. The capability of the present 4 invention to provide constant basin water temperature is directly applicable to steel mill operation, glass processing and resulting product quality and capacity. The capability of 6 the direct-drive system of the present invention and the fan to operate in reverse without 7 limitation allows more heat to be retained in the process water on cold days. This would 8 be accomplished by slowing the fan 12 or operating the fan 12 in reverse in order to 9 retain more heat in the tower and thus, more heat in the process water in the basin.
The variable process control system of the present invention can deliver infinite 11 temperature variation on demand to the process as required to support production and 12 improve control and quality of the product.

14 Air-Handling System for Heating, Ventilation and Air-Conditioning (HVAC) Office buildings, computer data centers, sport complexes, shopping malls and 16 skyscrapers are investing in Intelligent Building Systems that actively manage and 17 monitor the buildings for heating, cooling and humidity during changing weather 18 conditions. A properly operating HVAC system is paramount in maintaining the health, 19 safety and comfort of a building's occupants as well as maintaining and protecting the building's integrity and equipment within the building.
21 Accordingly, another aspect of the present invention is directed to an air-handling 22 system which may be utilized in a HVAC system. The air-handling system comprises at 23 least one direct-drive fan system that comprises a load bearing, variable speed motor 1 and a relatively large-diameter fan that is connected to the rotational shaft of the motor.
2 The air-handling system moves and balances air-flow through the HVAC
system. The 3 load bearing, variable speed motor rotates the fan at relatively slow rotational speeds in 4 order to facilitate balancing the HVAC system during dynamic weather conditions, provide energy savings and improve noise attenuation. The air-handling system uses 6 motor information for feedback to balance the thermal system in less time thereby 7 improving comfort and reducing energy consumption. The air-handling system also 8 eliminates or substantially minimizes system lead and lag with variable motor speed and 9 a variable process control system that is adaptive and which learns the process cooling demand by historical trending as a function of date and time. The air-handling system 11 uses feedback control loops, similar to the feedback control loops shown in FIG. 3 and 12 previously described herein. The air-handling system of the present invention can be 13 integrated with existing building sensors, thermostats and other electronic circuitry to 14 allow the HVAC system to anticipate thermal requirements based on trending, demand, weather station data and weather forecast data.
16 Referring to FIG. 29, there is shown a commercial HVAC system 3100 that 17 comprises a direct-drive air handling system 3150 in accordance with one embodiment 18 of the invention. Air-handling system 3150 comprises a load bearing, variable speed 19 motor 20 which has been described in the foregoing description and shown in FIGS. 5A
and 5B. Motor 20 includes the vibration and motor-heat sensors that were previously 21 described in the foregoing description and shown in FIG. 4. The aforesaid vibration 22 sensors sense the vibrations caused by the rotation of the fan and output signals that 23 represent the sensed vibrations. The motor-heat sensors sense the heat within the 1 interior of the motor and the heat of the motor stator and output signals that represent 2 the measured or sensed heat. Motor 20 directly controls the speed and torque of the 3 fan from one (1.0) RPM. A relatively large, diameter fan 3152 has a fan hub 3154 that 4 is directly connected to rotational shaft 24 of motor 20. In another embodiment, the fan 3152 is a one-piece fan assembly such as a wide chord fan with an integral hub or fan 6 hub system. However, it is to be understood that motor 20 may be used with any one of 7 a variety of fans. Fan 3152 operates within fan stack or ring 3160. Fan stack 3160 is 8 attached to fan deck 3170. Fan 3152 operates within fan stack or fan ring 3160 in order 9 to provide the proper fan-head to the particular application. In other embodiments, such as relatively large commercial ceiling fans, a fan stack or ring is not used.
Motor 20 ii rotates fan 3152 at a relatively slow speed. All modes of operation discussed in the 12 foregoing description, such as Soft Start and Soft Stop, can be implemented by the 13 direct-drive air handling system of the present invention. The plenum volume 3172 is 14 below the fan deck 3170. Rotation of fan 3152 moves air through a bank of condenser coils 3174. The plenum volume 3172 also allows a single axial fan to serve any shape 16 array of condenser coils. Motor 20 can be oriented so that motor shaft 24 is either 17 substantially vertical or substantially horizontal thereby allowing motor 20 to be used in 18 a variety of applications, such as exhaust and furnace blowers, mechanical mixers, 19 chillers, evaporators and pumps.
Direct-drive air handling system 3150 (a) improves wetted area or air flow around 21 the condenser coils 3174 and provides improved thermal management, (b) attenuates 22 noise as a result of slower speed fan and programmed Soft Start and Soft Stop modes 23 of operation, (c) provides variable process control and energy savings, (d) allows for 1 reverse operation of the fan for exhaust back pressure control and de-ice mode (e) can 2 be used with a relatively smaller condenser array thereby reducing weight, (f) uses 3 relatively less space of the installation envelope and promotes round duct work which 4 improves airflow, and (g) improves reliability, service and maintenance with a single fan that has one moving part. Fan 3152 is supported solely by the load bearing, variable 6 speed motor 20. As shown in FIGS. 5A and 5B, motor 20 has a bearing system that 7 enables the motor 20 to support and bear the fan loads while simultaneously 8 maintaining a critical rotor-to-stator gap. The critical rotor-to-stator gap ensures that 9 proper motor flux is generated in order to allow motor 20 to provide the required rotational speed and high torque. A variable frequency drive (VFD) device can be used ii to operate motor 20 as a low, variable speed motor that provides high torque even at 12 the low RPM of 1.0 RPM. Operating motor 20 with a VFD allows for controlled starts, 13 controlled stops and windmilling thereby reducing mechanical failures.
14 In other embodiments, an adjustable speed device (ASD) or variable speed device (VSD) is used in place of a variable frequency drive (VFD) device. In an 16 alternate embodiment, motor 20 is operated at a single speed. In such an alternate 17 embodiment, a VFD, ASD or VSD is not utilized.
18 FIG. 30A shows a commercial HVAC system 3200 in accordance with another 19 embodiment of the invention. HVAC system 3200 comprises direct-drive air-handling system 3150 shown in FIG. 29 with the addition of a down-stream, direct-drive 21 centrifugal blower 3250. FIG. 30B shows a top view of wide chord fan 3152. As shown 22 in FIGS. 31A and 31B, centrifugal blower 3250 comprises a cantilever fan 3252 that is 23 supported solely by load bearing motor 20. Such a configuration is referred to herein as 1 a single cantilevered bearing system. The single cantilevered bearing system allows 2 motor 20 to be integrated into the centrifugal fan 3252 so as to minimize installation 3 envelope and the width of the centrifugal blower 3250. Centrifugal fan 3252 comprises 4 fan hub 3254 which is connected to shaft 24 of motor 20. Motor 20 and fan 3252 are positioned within the interior of housing 3256. Motor 20 is connected to section 3258 of 6 housing 3256.
7 An alternate embodiment of the system shown in FIG. 31B is configured with an 8 "inside-out motor". In such an embodiment, the motor rotatable shaft is connected to 9 the centrifugal fan but the rotatable shaft does not rotate the fan.
Instead, the motor housing and stator are integral with the centrifugal fan to form one integral structure ii which rotates about the motor shaft.
12 In another embodiment, the centrifugal blower 3250 is configured so that motor 13 20 is positioned outside of plenum 3172.
14 An alternate embodiment of the centrifugal blower 3250 is shown in FIG.
32 as centrifugal blower 3260. Centrifugal blower 3260 comprises housing 3261 and a load 16 bearing, permanent magnet motor 3264 that is substantially the same in construction as 17 motor 20 except motor 3264 has a substantially longer rotatable shaft 3266. Centrifugal 18 blower 3260 comprises centrifugal fan 3268 which is supported by a dual bearing 19 system. This dual bearing system comprises the bearing system of motor 3264 and a second bearing 3270 that is mounted to housing 3261 and positioned at end 3272 of 21 shaft 3266.
22 In another embodiment, centrifugal blower 3260 is configured so that motor 3264 23 is positioned outside of plenum 3172.

1 Referring to FIG. 33, there is shown a commercial HVAC system 3500 that 2 comprises housing 3501, the first direct-drive air-handling system 3150, originally 3 shown in FIG. 29, and second direct-drive air handling system 3504.
Second air-4 handling system 3504 is a down-stream, direct-drive axial fan that comprises fan 3510 and load bearing permanent magnet motor 20. Fan 3510 comprises fan hub 3512 6 which is connected to shaft 24 of motor 20. Fan 3510 can be configured as any type of 7 fan as required to move air at various points through the air-handling system. For 8 example, there can be different motor- fan combinations in the same air-handling 9 system. In one embodiment, fan 3510 is a wide chord fan. As is known in the art, wide chord fans are configured to move large volumes of air at relatively low fan speed. Air ii handling systems 3150 and 3504 cooperate to move and balance air in the commercial 12 HVAC system. Using second air-handling system 3504 instead of a prior art centrifugal 13 blower results in a relatively shorter installation package with less weight and allows the 14 air-handling duct to have a round shape instead of a rectangular shape, which complements the circumference of the fan for required sealing and improved air-flow 16 through the duct work. Furthermore, using air-handling system 3504 instead of a prior 17 art centrifugal blower eliminates lead and lag thereby improving cooling performance 18 and reducing energy consumption. Using air-handling system 3504 also allows for 19 variable process control with feedback and supervision because fan 3510 is directly driven by motor 20. Motor 20 is configured so that fan 3510 can rotate in forward or 21 reverse directions. In one embodiment, a separate variable frequency drive device 22 (VFD) is used with each motor 20 of air-handling systems 3150 and 3504 in order to 23 rotate the fans in forward or reverse or bring the fans to idle. Using the VFDs also allow 1 implementation of the Soft Start and Soft Stop modes of operation which were 2 discussed in the foregoing description. Another important advantage is that air-handling 3 system 3504 can either eliminate or be combined with a prior art centrifugal blower 4 positioned at the end of an HVAC system to maintain system backpressure.
In some embodiments, variable speed devices (VSD) or adjustable speed 6 devices (ASD) are used to control each motor 20 of the air-handling systems 3150 and 7 3504.
8 Referring to FIG. 34, there is shown a block diagram of direct-drive air handling 9 system 3600 and corresponding variable process control system 3620 in accordance with another embodiment of the present invention. Air-handling system 3600 comprises ii a load bearing, electrically commutated motor (ECM) 3602. The motor 3602 comprises 12 a stator, rotor, rotatable shaft 3604 and integrated motor controller 3606. Fan 3608 is 13 connected to shaft 3604. In one embodiment, motor controller 3606 includes a 14 microprocessor that regulates speed and torque thereby alleviating the need for a separate feedback device. Motor controller 3606 is integrated into ECM 3602 and 16 includes an inverter that provides power signals and motor control signals in a manner 17 similar to a variable frequency device (VFD). In one embodiment, ECM
3602 is a 18 permanent magnet motor. In another embodiment, ECM 3602 is a switched reluctance 19 motor. In a further embodiment, ECM 3602 is an induction motor. The ECM

further includes vibration sensors that sense the vibrations of the fan and function in the 21 same manner as the vibration sensors of motor 20 as shown in FIG. 4. The 22 further includes temperature sensors that sense the temperature of the motor interior 23 and the heat of the stator and function in the same manner as the heat and temperature 1 sensors of motor 20 as shown in FIG. 4. The control system 3620 comprises digital 2 acquisition device (DAQ) 3624, industrial computer 3626 and a distributed control 3 system (DCS) 3628. The purpose and function of distributed control systems was 4 explained in the foregoing description (see DCS 315 in FIG. 2). In some embodiments, the DCS 3628 may be an existing building management system. Bi-directional 6 electronic data signal bus 3630 is in electronic signal communication with integrated 7 motor controller 3606 and DAQ 3624. Bi-directional electronic data signal bus 3631 is 8 in electronic signal communication with DAQ 3624 and industrial computer 3626.
9 Control system 3620 further includes a bi-directional electronic data signal bus 3634 that is in electronic signal communication with industrial computer 3626 and DCS 3628.
ii DAQ 3624 has data storage capability to store past demand data and trending data in a 12 manner similar to DAQ 200 discussed in the foregoing description and shown in FIGS. 2 13 and 4. DAQ 3624 functions in the same manner as DAQ 200 and, when combined with 14 motor-feedback signals, sensor signals and industrial computer 3626, provides a variable process control system that is adaptive and which learns the process cooling 16 demand by historical trending as a function of date and time thereby eliminating or 17 substantially minimizing system lead and lag.
18 HVAC systems typically utilize a plurality of pressure, temperature, air flow and 19 humidity sensors which output sensor signals 3640. In some scenarios, these HVAC
system sensors are pre-existing and are integrated with control system 3620.
21 Accordingly, these sensor signals 3640 are inputted into DAQ 3624 along with the 22 vibration sensor signals 3642 and motor-heat sensor signals 3644 which emanate from 23 corresponding vibration and heat sensors on or within ECM 3602. The vibration sensor 1 signals 3642 represent sensed vibrations resulting from rotation of fan 3608. The 2 motor-heat sensor signals 3644 represent the heat of the motor stator and the heat of 3 the interior of motor 3602. All sensor output signals 3640, 3642 and 3644 are then 4 further processed by industrial computer 3626. The power and motor control signals provided by the inverter of motor controller 3606 are also inputted into DAQ
3624 via 6 bus 3630 and then routed to industrial computer 3626 for further processing in order to 7 provide additional fan control, monitoring, supervision and integration with signals from 8 DCS 3628. Motor controller 3606 directly reads and monitors the poles of motor 3602 9 thereby eliminating a need for an encoder or specific motor feedback device. Motor controller 3606 always knows the direction of rotation and position of the motor rotor ii about its axis which allows ECM 3602 to rotate fan 3608 at variable speed and be 12 programmed with different ramp rates to accelerate and decelerate and hold at zero 13 (0.0) RPM to prevent windmilling. In an alternate embodiment, the motor 3602 includes 14 a feedback device. In one embodiment, the feedback device is an encoder.
In another embodiment, the motor 3602 is operated at a single speed.
16 Referring to FIGS. 35A and 35B, there is shown an HVAC system 3700 that 17 comprises a modified version of the air-handling system of FIG. 30A and the control 18 system 3620 shown in FIG. 34. Direct-drive air handling system 3710 comprises ECM
19 3602 that is shown in FIG. 34. Fan 3152 has fan hub 3154 which is connected to motor shaft 3604. Fan 3152 rotates within fan stack 3160 which is attached to fan deck 3170.
21 Fan 3152 was previously described herein and is shown in FIGS. 29 and 33. Rotation 22 of fan 3152 moves air through a bank of condenser coils 3174. The plenum volume 23 3172 is shown below fan deck 3170 and allows a single axial fan to serve any shape 1 array of condenser coils. Direct-drive centrifugal fan apparatus 3730 comprises an 2 electrically commutated motor (ECM) (not shown) that is identical in construction to 3 motor 3602 and includes a rotatable shaft and an integrated motor controller (not 4 shown). Control signals from DAQ 3624 are inputted into the integrated motor controller of centrifugal fan apparatus 3730 via bi-directional electronic data signal bus 3752.
6 HVAC system 3700 further includes temperature, pressure, air-flow and humidity 7 sensors 3760. The signals outputted by sensors 3760 are inputted into DAQ
3624 via 8 wire or cable network 3780 or via wireless system. Vibration sensor signals and motor-9 heat sensor signals (not shown) from each ECM of air-handling system 3710 and centrifugal fan apparatus 3730 are also inputted into DAQ 3624 via a wiring or cable ii network (not shown). The vibration and motor-heat sensors of each ECM, DAQ 3624, 12 industrial computer 3626, DCS 3628 and the HVAC system sensors 3760 cooperate to 13 provide additional monitoring, supervision and control. Existing HVAC
system 14 thermostats and weather stations can be integrated into the system shown in FIG. 35A
in order to allow this system to anticipate demand based on current weather conditions 16 and forecast data as well as trending and past demand data that is stored in DAQ 3624.
17 Referring to FIG. 36, there is shown HVAC system 3800 that comprises the 18 direct-drive air handling systems 3150 and 3504 of FIG. 33, a control system 3810 and 19 temperature, pressure, air-flow and humidity sensors 3840. Control system 3810 comprises a first variable frequency drive (VFD) 3820, data acquisition device (DAQ) 21 3822, industrial computer (IC) 3824 and second VFD 3826. Control system 22 further includes distributed control system (DCS) 3828. First VFD 3820 controls motor 23 20 of direct-drive air handling system 3150 and second VFD 3826 controls motor 20 of 1 direct-drive air handling system 3504. First VFD 3820 is in electronic signal 2 communication with DAQ 3822 via bi-directional electronic data signal bus 3830.
3 Second VFD 3826 is in electronic signal communication with DAQ 3822 via bi-4 directional electronic data signal bus 3831. DAQ 3822 is in electronic signal communication with industrial computer 3824 via bi-directional electronic data signal 6 bus 3832. Industrial computer 3824 is in electronic signal communication with DCS
7 3828 via bi-directional electronic data signal bus 3834. Temperature, pressure, 8 humidity and air-flow sensors 3840 are in electronic signal communication with DAQ
9 3822 via wiring or cable network 3850 or via a wireless system. Rotation of the fans 3152 and 3510 move air through the bank of condenser coils 3174. DAQ 3822 ii functions in the same manner as DAQ 200 and, when combined with motor-feedback 12 signals, sensor signals and industrial computer 3824, provides a variable process 13 control system that is adaptive and which learns the process cooling demand by 14 historical trending as a function of date and time thereby eliminating or substantially minimizing system lead and lag. Furthermore, the vibration and motor-heat sensor 16 signals (not shown) from each motor 20 cooperate with DAQ 3822, industrial computer 17 3824, DCS 3828 and HVAC system sensors 3840 to provide additional monitoring, 18 supervision and control. Existing HVAC system thermostats and weather stations can 19 be integrated into the system shown in FIG. 36 in order to allow this system to anticipate demand based on current weather conditions and forecast data as well as trending and 21 past demand data that is stored in DAQ 3822.
22 In another embodiment, the data acquisition devices (DAQ) of the control 23 systems described above are programmed to implement the method for optimizing 1 energy in an HVAC system that is described in international application no.
2 PCT/US2012/028007 entitled "Systems And Methods For Optimizing Energy And 3 Resource Management For Building Systems" and published under International 4 Publication No. WO 2012/122234. The disclosures of the aforesaid international application no. PCT/US2012/028007 and International Publication No. WO
6 2012/122234 are hereby incorporated by reference.
7 In another embodiment, the data acquisition devices (DAQ) of the control 8 systems described above are programmed to implement the method for determining 9 parameters for controlling a HVAC system that is described in U.S
application no.
13/816,325 entitled "Methods for Determining Parameters for Controlling An HVAC
ii System" and published under Patent Application Publication No. US
2013/0144444.
12 The disclosures of U.S. application no. 13/816,325 and publication no.
US
13 2013/0144444 are hereby incorporated by reference.
14 In another embodiment, the data acquisition devices (DAQ) of the control systems described above are programmed to implement the method for controlling 16 HVAC systems using set-point trajectories that are described in U.S
application no.
17 13/324,140 entitled "Method for Controlling HVAC Systems Using Set-Point 18 Trajectories" and published under Patent Application Publication No. US
2013/0151013.
19 The disclosures of the aforesaid U.S. application no. 13/324,140 and Publication No.
US 201 3/01 51013 are hereby incorporated by reference.
21 In other embodiments, the motor in the direct-drive air-handing system is a 22 permanent magnet motor that can be configured with either the fan being rotated by the 23 motor shaft or an "inside-out motor" wherein the stator is connected to the fan hub and 1 the rotor is stationary, such as in a ceiling fan application, or in the alternate 2 embodiment of the system shown in FIG. 31B described in the foregoing description.
3 Other applications include direct drive ceiling fans, furnace blowers, blast furnace 4 fans, mechanical mixers and chillers, condenser coolers and exhaust fans, such as the type used in tunnels.
6 While the foregoing description is exemplary of the present invention, those of 7 ordinary skill in the relevant arts will recognize the many variations, alterations, 8 modifications, substitutions and the like are readily possible, especially in light of this 9 description, the accompanying drawings and the claims drawn hereto. In any case, because the scope of the invention is much broader than any particular embodiment, ii the foregoing detailed description should not be construed as a limitation of the present 12 invention, which is limited only by the claims appended hereto.

Claims (17)

CLAIMS:
What is claimed is:

1. A heating ventilation and air-conditioning system (HVAC) comprising:
a condenser coil;
a fan;
a variable speed, load bearing permanent magnet motor comprising a casing having an interior, a stator and rotor located in the interior of the casing for creating flux, and a rotatable shaft connected to the fan, the motor comprising a bearing system for bearing fan loads and enabling the variable speed, load bearing motor to rotate the fan in a forward direction or reverse direction, wherein rotation of the fan causes air-flow through the condenser coil, the bearing system comprising a spherical roller thrust bearing for absorbing the thrust loads resulting from the weight of the fan and the airflow produced by rotation of the fan, a cylindrical roller bearing for opposing the radial loads at the thrust end of the rotatable shaft, and a tapered roller output bearing for opposing the reverse thrust loads resulting from reverse rotation of the fan and yaw loads; and a device to generate electrical signals that cause rotation of the rotatable shaft of the motor in order to rotate the fan.

2. The heating ventilation and air-conditioning system according to claim 1 further comprising a first bearing housing for housing the tapered roller output bearing and a second bearing housing for housing the cylindrical roller bearing and the spherical roller thrust bearing.

3. The heating ventilation and air-conditioning system according to claim 2 further comprising a first seal to isolate the first bearing housing from the interior of the casing and a second seal to isolate the second bearing housing from the interior of the casing.

4. The heating ventilation and air-conditioning system according to claim 3 wherein the motor further comprises a motor shaft seal in tandem with the first and second seals.

5. The heating ventilation and air-conditioning system according to claim 4 wherein the motor shaft seal comprises a bearing isolator.

6. The heating ventilation and air-conditioning system according to claim 1 wherein the motor comprises a load bearing permanent magnet motor.

7. The heating ventilation and air-conditioning system according to claim 1 wherein the motor includes at least one sensor for measuring vibrations and outputting signals representing the measured vibrations.

8. The heating ventilation and air-conditioning system according to claim 7 wherein the motor includes at least one temperature sensor to measure the temperature of the interior of the casing.

9. The heating ventilation and air-conditioning system according to claim 7 wherein the motor includes at least one temperature sensor positioned on the stator to measure the temperature of the stator.

10. The heating ventilation and air-conditioning system according to claim 7 further comprising a signal processor for processing the signals outputted by the at least one vibration sensor.

11. The heating ventilation and air-conditioning system according to claim 1 wherein the motor further comprises:
at least one vibration sensor positioned within the interior of the casing;
at least one temperature sensor positioned within the interior of the casing;
an internal wiring network within the interior of the casing and electrically connected to the at least one vibration sensor and the at least one temperature sensor;
a signal connector attached to the casing and electrically connected to the internal wiring network; and external wires connected to the signal connector for routing sensor signals to an external signal processing resource.

12. The heating ventilation and air-conditioning system according to claim 1 wherein the device to generate electrical signals comprises a variable frequency drive device.

13. The heating ventilation and air-conditioning system according to claim 1 wherein the device to generate electrical signals comprises a variable speed drive device.

14. The heating ventilation and air-conditioning system according to claim 1 wherein the motor is oriented such that the rotational shaft of the motor is vertically oriented.

15. The heating ventilation and air-conditioning system according to claim 1 wherein the motor is oriented such that the rotational shaft of the motor is substantially horizontal.

16. The heating ventilation and air-conditioning system according to claim 1 wherein the motor is oriented such that the rotational shaft is oriented at an angle.

17. A heating ventilation and air-conditioning system (HVAC) comprising:
a condenser coil;
a fan;
a variable speed, load bearing permanent magnet motor comprising a casing having an interior, a stator and rotor located in the interior of the casing for creating flux, and a rotatable shaft connected to the fan, the motor comprising a bearing system for bearing fan loads and enabling the variable speed, load bearing motor to rotate the fan in a forward direction or reverse direction, wherein rotation of the fan causes air-flow through the condenser coil, the bearing system comprising a spherical roller thrust bearing for absorbing the thrust loads resulting from the weight of the fan and the airflow produced by rotation of the fan, a cylindrical roller bearing for opposing the radial loads at the thrust end of the rotatable shaft, and a tapered roller output bearing for opposing the reverse thrust loads resulting from reverse rotation of the fan and yaw loads, said motor further comprising at least one vibration sensor positioned within the interior of the casing, at least one temperature sensor positioned within the interior of the casing, an internal wiring network within the interior of the casing and electrically connected to the at least one vibration sensor and the at least one temperature sensor, a signal connector attached to the casing and electrically connected to the internal wiring network, and external wires connected to the signal connector for routing sensor signals to a signal processing resource; and a device to generate electrical signals that cause rotation of the rotatable shaft of the motor in order to rotate the fan.