GB2239107A

GB2239107A - Motor control system

Info

Publication number: GB2239107A
Application number: GB8927332A
Authority: GB
Inventors: John Barrie Timmons
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-12-04
Filing date: 1989-12-04
Publication date: 1991-06-19
Also published as: GB8927332D0

Abstract

The speed/torque of a motor 5 is controlled by sensing the number of people using a building or facility. The use of two sensors 2 enables the control to differentiate between people entering and leaving the building. A counter 3 provides a signal 6 proportional to the usage and the motor speed 5 is regulated accordingly. In this example a frequency inverter 4 is used on a three phase supply 7. An application of this invention would be to control the air changes in a ventilation system as related to the building occupancy. Another example would be to control the water circulating rate at a swimming pool relative to the number of swimmers. <IMAGE>

Description

MOTOR CONTROL SYSTEM This invention relates to an automatic speed control of motors by sensing the usage of the facility.

Speed controllers for motors are becoming a reconised method of conserving energy. The signal operating the controller is of course dependant on the system to which the motor is attached. There are available units which control speed via pressure, temperature, chemical reaction times, to give but a few examples.

There are motors however whose demand is proportional to the usage of the building, for example with air conditioning, larger numbers of people require higher air turnover rates to maintain the quality of air. Another example of this would be the circulating motors at a public swimming pool where the water pollution is proportional to the number of swimmers.

Therefore the pumping capacity can be altered to suit the demand by "counting" the people using the facility.

A specific embodiment of the invention will now be described by way of example with referance to the accompanying drawing in which: Fig. 1 Shows a schematic plan of the automatic system.

Referring to the drawing the automatic control consists of one or more sensors 2 placed in an entrance hall, passage between changing rooms and pool hall 2 etc, where the people using the facility must pass.

The use of two sensors in one area enables the counter device 3 to differentiate between people entering and leaving, the facility. Thus enabling more accurate control of the motor speed as a proportion of the people using the facility.

The sensors could for example be of the infa-red or photo electric type.

Switches could be used on entrance doors to the building or changing rooms, which can supply the signal required to control the speed of the motors 5 The required signal could be supplied by the cash till buttons, for example adult swims used to control the large pool circulation whilst junior swims used for the learner pool.

The counter 3 could be a microprocesser which sets minimum and maximum motor speeds, rates of change, and a clock to override the counter at known maximum usage times. The output of the counter 6 in this example is controlling the motor speed via a frequency invertor 4 in the 3 phase supply 7. The output from the counter could also control single phase, or D.C. motors. An alternative would be to use the counter output 6 to regulate a servo 4 whose output would in turn control an internal combustion engine driven fan or pump.

Claims

1 A motor control system which has the speed/torque of the motor essentially controlled by sensing the number of people using the building and facility.

2 As in Claim 1 where the sensors are counting the people entering into a swimming pool hall or area and the information used to control the speed of the pool pumps and hence the circulation rate of the water.

3 As in Claim 1 where the sensors are controlling the fans in an air conditioning plant and thus the air turnover rate of the building.

4 A motor control system substantially as described herein with referance to the Figure of the accompanying drawing.

Amendments to the claims have been filed as follows 1. A system for controlling the water circulation rate for filtration and/ or sterilisation purposes of indoor and outdoor swimming pools comprising means for monitoring the number of swimmers using said swimming pool, and controlling the water circulation rate in dependence on such number.

2. A system according to claim 1, in which the or each monitoring means comprises a counter means for responding to swimmers entering the swimming pool or area thereof and the counter controlling the water circulation rate with respect to the number of swimmers in a given period of time. I.e. to maintain quality water conditions with respect to the theory of progressive dilution.

3. A system as in claim 1 and 2 where the means for monitoring the number of swimmers comprises a counter means using infa red sensors in an area through which swimmers pass prior to swimming effectively providing an automatic system.

4. As in claim 1, 2 and 3 where the system is capable of distinguishing between people entering and leaving the facility (by the same route) by which sensor receives the signal first, the system counts people in and out giving accurate control.

5. A system as in claim 1 and 2 where the means for monitoring the number of swimmers comprises a counter means using the frequency and/or duration of doors opening or closing through which swimmers pass, effectively providing an automatic system

6. A system as in claim 1 and 2 where the means for monitoring the number of swimmers comprises a counter means using signals from the till buttons at said swimming pool to provide information effectively providing an automatic system.

7. A swimming pool water circulation rate control system substantially as described herein with referance to the accompanying drawing.