MX2009005501A

MX2009005501A - Device for the predictive monitoring and thermal protection of motors and electrical machines.

Info

Publication number: MX2009005501A
Application number: MX2009005501A
Authority: MX
Inventors: Francisco Manuel Togno Murguia
Original assignee: Francisco Manuel Togno Murguia
Priority date: 2009-05-25
Filing date: 2009-05-25
Publication date: 2010-11-24
Also published as: WO2010137935A1

Abstract

The novel features of the invention are summarised below. The device conditions the start-up of the motor to the state thereof in terms of age and moisture level, as detected in the insulator of the sector. The program of the device takes account of climatological variables to ensure that the motor is not needlessly disconnected and that it is always in response to an exact increase so that the recovery capability of the sector varnish is not exceeded. Depending on the program, an audible and visible alarm is triggered when an anomaly approaches the disconnection threshold. In addition, the device constantly monitors and displays the internal temperatures. The device can be installed in a motor and check same wirelessly or via cables when the motor is more than one kilometre from the monitoring device and screen. When the motor is disconnected, the device leaves the key that represents the reason for the disconnection on the screen.

Description

DEVICE FOR PREDICTIVE MONITORING AND THERMAL PROTECTION OF ENGINES AND ELECTRICAL MACHINES DESCRIPTION OBJECT OF THE INVENTION The object of this invention is to provide the industry and any user of machines and electric motors, a new reliable and precise monitor protector that efficiently protects the production that the motor or machine executes, allowing to obtain the maximum performance with the less deterioration for the engine. All electric motors and machines when they suffer an anomaly such as: phase fall, forced rolling, over work requirements, voltage imbalance, mechanical misalignment, etc., increase the winding temperature, which due to thermal inertia, this increase Continues for a variable time, even after the motor has been disconnected, this device resolves this unwanted situation. This new device, following the standard IEC standards, guarantees that the programming of the stoppage of the same, will be at the correct time, since it conforms to the specific norm of the manufacturer, adjusting automatically after being programmed, with the climatological variables (temperature and height above sea level) of the engine environment surveyed. This device measures the internal temperature of the motor or machine, and that of the surrounding environment and compares the difference between the two, and as a result, the disconnection threshold goes up or down.

In other words, each moment calculates the variable capacity that the environment has to absorb the temperature that the motor dissipates. Also, with a screen, it shows the hottest temperature of the coils, allowing to anticipate and correct any anomaly detected, when it starts, and if by X circumstance, the temperature reading is not verified, it will call the attention of the user with an alarm , alerting you of a problem, before it automatically stops the machine or motor, leaving after the fixed disconnection on the screen, the reason why the shutdown of the supply of electricity to the motor was ordered. All this information is transmitted over a cable or wirelessly to the computer screen or to a computer (as installed). For the programming of the constant of the limit of disconnection of the apparatus, the comparative base was considered the table 1EC of thermal classification of windings, type Y, A, E; B, F, H, according to NEMA MG-1, as well as the height above sea level, where the motor or apparatus is fixed, as well as the result of the previous analysis of the conductive resistivity of the motor winding carried out by the same device. BACKGROUND Due to the fact that currently there are various methods of protection for electric motors and machines, which, directly and indirectly, try to avoid the deterioration or total destruction of the machine or motor in their charge, and considering that none of the they take into account together the related environmental variables among others, with the state of aging of the engine in question, thus reducing the effectiveness of protection offered by them, which in addition to the loss of the engine, unnecessarily affects production Another important sector of machines and electric motors, which nowadays operate in the industry, have no protection whatsoever, and for this reason they are an important market to be satisfied with the proposed sensors, which can be installed with relative ease, the same, They can also directly replace the RTD, PT100 thermistors, which are used in some cases for this purpose, and when replaced by ours (KTYs), the following aspects are substantially improved: low cost compared with the RTDs; high sensitivity, 5 Ohms for each degree Celsius, compared to 0.39 Ohms for each degree Celsius of the RTDs, so they make the present development an attractive system in the implementation of protection. The proposed sensor, can operate in the temperature range of minus 40 degrees centigrade, at plus 300 degrees Celsius, covering the range of all types of thermal insulation (from Y to H), to the rest of the sensor that we occupy, it presents greater protection against other adverse circumstances that can irreversibly damage the engine, particularized by having a approach more in accordance with the specific reality of the conditions that surround the place where the engine is implanted. For these reasons and considering that all the causes of damage, not by blow or explosion, of an electric motor, are finally manifested by the temperature rise of its electric windings, which when exceeding the resistance limit of the thermal insulation, are damaged irreversibly; therefore, it is proposed to design and build an electronic protector and monitor that estimates the variable ambient temperature and atmospheric pressure conditions that are related to each other, affecting the melting point of the insulator of the motor or machine coils, which will satisfy adequately real market to electric motors and machines, which have poor thermal protection, or none.

BRIEF DESCRIPTION OF THE FIGURES Figure 1 schematic block diagram DETAILED DESCRIPTION OF THE INVENTION The characteristic details are clearly shown in the following description and in the attached drawing marked as figure 1, an electronic protector and monitor, for electric motors and machines, which will estimate the ambient temperature, the atmospheric pressure and the thermal resistivity of the winding of the coils, to calculate the maximum suitable temperature allowed by the type of insulation installed in the mentioned coils Same that are censed and protected, with the following characteristics. It will show on a luminous screen the temperature of the hottest winding, by means of temperature sensors located between them, maximum at 120 ° mechanical, inside the aforementioned electric winding. The temperature range will encompass the thermal resistivity of all types of insulating varnishes for coils existing in the market, with a resolution of 1 ° C, which will be shown on the screen and another digit will indicate the temperature scale used, either in centigrade or degrees Fahrenheit. Through a control program and according to the type of classification of the thermal resistance of the varnish installed in the coils of the motor or machine, the necessary information for its operation will be entered into the device.

Figure 1 is a schematic block diagram, which clearly describes the integration of the elements of a thermal monitor protector for engines and induction machines, which estimates the atmospheric pressure and the ambient temperature surrounding the engine to calculate the temperature rise maximum in electric windings. A three-phase power source (10) that is responsible for supplying the electrical emergy to the motor (12) or induction machines. The electromechanical contactor (1 1), which, through its control coil, transfers the power from the three-phase power source (10) to the motor or induction machine (12). The control system is based on the microprocessor (13), the actions of control and protection of the motor (12), are given by 3 or more thermal sensors KTYS (14), which, each, are distributed maximum 120 ° mechanical inside the windings of the motor stator (12); the hottest temperature of the 3 or more windings will be recorded, which will be shown through a luminous screen (15); by means of a programming keypad (16), the maximum allowed temperature limit will be entered, according to the type of thermal classification of the motor (12) and to the atmospheric pressure where said motor (12) is installed; it will also be stored permanently in a serial memory (17); a fourth thermal sensor (18) will be used to measure the ambient temperature surrounding the motor (12), and this will be used, by the control system (13), to calculate, using a table that estimates the ambient temperature surrounding the motor (12), the maximum permissible limit in the motor windings (12); a 2-wire signal conditioning system (19), will be responsible for energizing the thermal sensors (14 and 18), which, due to their nature, significantly simplify the design of the signal conditioning system (19) .

A serial analog or equivalent analog converter will be the interface between the 2-wire signal conditioner (19) and the control system based on a microprocessor (13): when any of the internal temperatures of the motor windings (12) ) has reached dangerous levels exceeding 90% of the maximum temperature degrees allowed by the type of insulation, the control system (13), will activate an audible and / or visible alarm (20); which will be deactivated only if the temperature decreases below 90%, mentioned above; when any of the 3 temperatures of the internal windings of the motor (12) has reached the maximum temperature limit, the control system (13) will deactivate the power supply from the three-phase power source (10), by de-energizing the contactor control coil (11) through the relay (21), although the temperature that caused the disconnection of the three-phase power source (10) to the motor (12) has dropped below the maximum value allowed, the control system (13) will reconnect only when it has been manually reset, our invention also has a short circuit protection given by humidity at engine start (12), to prevent the destruction of the engine that is wet or immersed in water, by means of a sensor of low electrical conductivity connected between the insulating varnish of the winding of the coils and the motor housing (12), the microprocessor (13), before energizing the starter coil (1 1) sends a small impulse of low amperage and voltage, to measure the presence of conductivity, synonymous among others of water or carbon, if the presence of conductivity is positive, the r Elevator (21) will not energize the contactor coil (11), thus avoiding the eminent destruction of the motor (12), so that the motor (12) can start, all traces of humidity must be eliminated; the monitor in mention, has another protection to disconnect automatically and without warning to the motor (12), so that when for whatever reason, it is blocked (glued bearing), the microprocessor (13) will determine through the hottest sensor (14) the occurrence of a derivative sudden thermal transient temperature change, with respect to a pre-established threshold of time, presenting a behavior of asymptotic character.

Claims

CLAIMS Having sufficiently described my invention, I consider as a novelty and therefore claim as my exclusive property, what is contained in the following clauses:

1 . - Device for the predictive monitoring and thermal protection of electric motors and machines characterized, because it has a group of thermal sensors that transmit information of the windings of the stator and of the surrounding environment to an intelligent microprocessor, that through an analog converter, the interprets as standard temperature values, which are checked, by means of an intelligent control program of the device, together with the value corresponding to the installation height with respect to sea level, alarm trigger temperature and other information that will be incorporated into the memory serially organized to automatically increase or decrease the changing engine disconnection temperature, depending on the result of the circumstantial climatic variations.

2. - Device for predictive monitoring and thermal protection of motors and electrical machines characterized, because it has a thermal monitor protector that shows on a luminous digital display the temperature of the hottest coil of the stator, as well as the external environment surrounding the motor that protects and censuses.

3. - Device for the predictive monitoring and thermal protection of electric motors and machines characterized, because it has a thermal protection for electric motors particularized because it disconnects the motor using a relay connected in series to the starter coil when it reaches the preset variable limit, or when the program installed in its memory considers that the thermal rise speed drastically exceeds the relevant levels of increase.

4. - Device for predictive monitoring and thermal protection of electric motors and machines characterized, because the protector is designed with a mechanism that provides a pulse of low voltage and amperage to measure the surface conductivity of the stator insulation by carbonization or humidity conditioning the Start at an allowable level of dielectric strength.

5. - Device for predictive monitoring and thermal protection of electric motors and machines characterized, because said protector is constituted by the particular qualities of its thermal sensors (TY's), based on them its unique 2-wire transmission and reception scheme whose reach exceeds 100 meters distance without detracting from its efficiency.

6. - Device for predictive monitoring and thermal protection of engines and electrical machines characterized, because according to the program installed in its memory, it automatically shows the cause that caused any disconnection of the motor.