RU1793379C - Device for measuring rotation speed of asynchronous electric motor with short-circuited rotor - Google Patents

Abstract

And the invention relates to the technique of electrical measurements of non-electric quantities, and more specifically to devices for measuring the speed of asynchronous motors (AM) with a squirrel-cage rotor. The purpose of the invention is to expand the scope of application. The voltage is supplied to the stator windings AD 1 from the industrial frequency source 2 through the regulator 3. From the high frequency generator 4, through the isolation capacitors 5, the high voltage voltages are supplied to the beginning and end of one of the phase windings 6 of the motor stator. When the AM rotates from the beginning of the stator windings 9 through isolation capacitors 8 and a high-pass filter 7, a high-frequency EMF is proportional to the rotational speed of the motor rotor. 1 ill.

Description

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The invention relates to techniques for electrical measurements of non-electrical quantities.

The purpose of the invention is to expand the scope.

The drawing shows a functional diagram of the device.

A device for measuring the speed of a squirrel-cage induction motor 1 comprises an industrial frequency power supply 2 connected to the stator windings of the motor through a voltage (frequency) chopper-regulator 3, a high-frequency alternating voltage generator 4 connected through 5 k isolation capacitors one of the phase windings of the stator of the motor, a high-pass filter 7 connected to the beginning of two other phase windings 9 of the motor by an input through isolation capacitors 8, and an output to The test device 10 or (and) to the input of the voltage regulator 3.

The device operates as follows. -....-.-.; -. . ...

A voltage is supplied from the power supply source 2 to the controller 3 and the high frequency generator A. From the regulator 3, the power voltage is supplied to the stator winding of the motor 1. From the high-frequency generator 4, which is powered by source 2

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Formula A device for measuring the speed of an asynchronous squirrel-cage induction motor, comprising an industrial frequency power supply connected to the stator windings of the motor included in the star through a chopper-regulator voltages and measuring device, resulting in that, with

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of industrial frequency, through isolation capacitors 5, an alternating single-phase high-frequency voltage significantly exceeding the industrial frequency is supplied to the beginning and end of one of the phase windings of the motor stator. If the rotor of the motor 1 does not rotate, then there is no high-frequency voltage at the beginning of two other phase windings 9 of the stator of the induction motor, since the vector of the high-frequency linear EMF at the beginnings of the phase windings 9 is 90 degrees apart from the vector of the high-frequency phase EMF on the winding used motor stator. ;

When the motor rotates, the high-frequency emf at the beginning of the stator windings 9 is proportional to the rotational speed of the motor rotor and is independent of the high-frequency carrier. Said high-frequency EMF through isolation capacitors 8 and a high-pass filter 7 can be used as feedback from the rotor speed to control the regulator 3 or connected to a measuring device 10 that controls the rotor speed of the motor. Separating capacitors 5, 8 serve to decouple the output of the generator 4 and the input of the filter 7 from high voltage industrial frequency.

In order to expand the scope of application, a high-frequency alternating voltage generator is connected to one of the phase windings of the motor through an isolation capacitor, and the beginning of the other two phase stator windings are connected to a measuring device and / or to the input of the regulator-chopper via isolation capacitors and a high-pass filter for example