SU1182447A1 - Apparatus for fault finding in short-circuited rotor of asynchronous motor - Google Patents

Abstract

A DEVICE FOR DETECTING DAMAGE TO A SHORT CAMERED: ROTOR OF AN ASYNCHRONOUS MOTOR, containing a speed sensor connected by an output to the first inputs of the first and second elements And connected to the outputs of the corresponding trigger inputs. The first meter and the rectifier, which is tacted by the fact that, in order to expand the functionality of the device, the power consumption sensor, the first and second low-pass filters, the frequency divider, the first and second pulse drivers, the nonlinear converter, the driver were introduced a sawtooth pulse, a second meter, a differential amplifier, a threshold element and a quiver, the output of the power consumption sensor connected via a frequency divider to the inputs of the first and second drivers: pulse S, connected by outputs, respectively, with the second inputs of the first and second elements, And the output of the trigger is connected through a serially connected driver of sawtooth pulses and the first low frequency filter to the input of the first meter and the first input of a differential amplifier connected to the second input through a serially connected nonlinear converter, second filter low frequency and expander with the output of the power sensor, the output with the input of the second meter directly, and through the threshold element nt: C INPUT indicator.

Description

one

The invention relates to instrumentation technology and can be used to control induction motors during operation.

The purpose of the invention is to expand the functionality of the device by providing automation for monitoring and diagnosing faults.

The drawing shows a block diagram of the proposed device.

The device contains a consumed sensor 1, power, a frequency divider 2, the first 3 and second 4 pulse shapers, the first 5 and second 6 elements And, the sensor 7 turns the trigger 8, the driver 9 sawtooth pulses, the first filter 10 low frequency, the first meter 11 , differential amplifier 12, nonlinear converter 13, second low-frequency filter 14, rectifier 15, second meter 16J threshold element 17, indicator 18. The output of speed sensor 7 is connected to the first inputs of the first 5 and second 6 And elements connected by the outputs with the trigger inputs B. The output of the sensor 1 power consumption is connected through a frequency divider 2 to the inputs of the first 3 and second 4 pulse shaper connected by the outputs respectively to the second inputs of the first 5 and second 6 elements I. The output of the trigger 8 is connected through serially connected shaper 9 sawtooth pulses and the first low-frequency filter 10 with the input of the first meter 11 and with the sing input of a differential amplifier 12 connected by a second input through a series-connected nonlinear transform The device 13, the second low-frequency filter 14 and the rectifier 15 with the output of the power sensor 1, the output with the input of the second meter 16 directly, and through the threshold element 17 with the input of the indicator 18.

The device works as follows.

Sensor 1 measures the magnitude of the consumed power of the motor or, at a constant value of the supply voltage, the magnitude of the stator current. The frequency of the signal from the sensor. one

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is determined by the frequency of the network, in the frequency of the signal from the speed sensor 7, the speed of rotation of the rotor. Frequency equalization is performed by frequency divider 2, the division ratio is equal to the number of pole pairs of the stator winding. A narrow, rectangular signal appears in the first half at the output of shaper 3.

period, and at the output of the former 4, a similar narrow, rectangular signal appears with a phase shift of 180, t, eo at the beginning of the second half period. During engine operation

the period between pulses from the speed sensor 7 is slightly longer than the periods between the pulses from the formers 3 and 4. When the pulses from the speed sensor 7 and the driver 3 coincide, the output of the element 5 appears. And a signal appears that flips trigger 8; After a time equal to half the period of the slip frequency, the pulses from the turn sensor 7 and the former 4 coincide, the output of element 6 appears. A signal appears which transfers trigger 8 to the initial state. Consequently,

the switching period of the trigger 8 is equal to the slip period. When switching the trigger 8, a signal appears at the output of the former 9 sawtooth pulses, the frequency of which

depends on the period of the signal at the output of the trigger 8. The low-frequency filter 10 produces a constant separation, which is directly proportional to the amount of slip. This

the signal is monitored by a meter

11. Using the rectifier 15 and the low-frequency filter 14, the variable signal from the sensor 1 is converted into a constant signal. The Converter 13 has a nonlinear transmission, the characteristic that provides the reference to the input of the differential amplifier 12 signal proportional to the reference value

slip values for a given load value, the relationship between them is non-linear. The load value is set to the input of the converter 13 by a signal from the output

a low-frequency filter 14 proportional to the amount of power consumed by the motor and, consequently, the magnitude of the load.

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With good rotor bars at the output of amplifier 12, there is no signal. When part of the rotor rods of an induction motor breaks, this leads to an increase in its resistance and, consequently, to an increase in slip. Equality of signals on

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the input of the differential amplifier 12 is disturbed and a signal appears at its output proportional to the magnitude of the damage to the rotor. This signal, that is, measuring 16, and when the threshold is reached, the element 17 is signaled by indicator 18.

Claims (1)

A DEVICE FOR DETECTING DAMAGES OF SHORT-CLOSED • ROTOR OF ASYNCHRONOUS MOTOR, comprising a speed sensor connected by an output to the first inputs of the first and second elements And connected by outputs to the corresponding inputs of the trigger. the first meter and rectifier, characterized in that, in order to expand the functionality of the device, a power consumption sensor, first and second low-pass filters, a frequency divider, first and second pulse shapers, a nonlinear converter, a sawtooth pulse shaper are introduced into it , a second meter, a differential amplifier, a threshold element and an indicator, and the output of the power consumption sensor is connected via a frequency divider to the inputs of the first and second pulse shapers, soy output signals respectively with the second inputs of the first and second elements AND, the trigger output is connected through serially connected sawtooth pulse shaper and the first low-pass filter to the input of the first meter and to the first input of the differential amplifier connected to the second input through a series-connected nonlinear converter, the second low-pass filter and a rectifier with the output of the power sensor, the output with the input of the second meter directly, and through the threshold element; with the input ind ikator. 1 1182447 2