SU1176419A1 - Device for checking ball bearings of electric machine - Google Patents

Abstract

A DEVICE TO CONTROL BALL BEARINGS OF ELECTRIC MACHINE containing an electrical circuit connected to the machine terminals with a current ripple sensor, a notch filter connected in series with it, and a frequency meter, characterized by that, in order to increase the control accuracy, a phase detector, a controlled oscillator, an intermediate frequency filter, a rms voltage meter, a capacitor and a mixer, the first input of which is connected to the output of the notch filter, are introduced into it, the output is connected to the first input of the phase detector and the input intermediate frequency filter, the output of which is connected to the second input of the phase detector, to the output of which through the capacitor is connected the input of the meter rms voltage and directly in one controlled generator, the output of which (l is connected to the frequency meter and the second input of the mixer.

Description

Od 1

WITH

The invention relates to electric machines and is intended for use in the process of operation and maintenance, in particular, to determine the technical condition of the rolling bearings of electromagnets without disrupting.

The purpose of the invention is to increase the accuracy of the control.

The drawing shows a functional diagram of the proposed device.

The device includes a current pulsation sensor 1, a notch filter 2, mixers 3, intermediate frequency filter 4, frequency meter 5, controlled generator 6, phase detector 7, transmitter 8 of the root-mean-square voltage, capacitor 9 and electrical circuit 1 connected via pulsation sensor 1 to the terminals of the electric machine 11,

The device works in the following way,. From the current ripple sensor 1, which can be used as a shunt in the circuit of an electrical machine, contains a variety of its oral components, is fed to a notch filter 2, which suppresses the largest components in the current ripple spectrum that does not carry diagnostic information . For example, in DC machines, the maximum component of the ripple source of the supply voltage (100 Hz) for the source of rectifying voltage of the mains supply is suppressed, and in AC machines the main harmonic of the supply voltage, Rejection filter 2 can be fixed frequency settings, and with automatic adjustment. From the output of the rejection filter 2, the signal goes to the first input of the mixer 3, for which it is more expedient to use a balanced mixer, which gives the minimum number of combinations of frequencies of input voltages at the output. The second input of the mixer 3 receives the voltage from the controlled oscillator 6, which is tuned to the expected frequency of rotation of the balls with the disconnected communication with the phase detector 7, controlling the frequency by the frequency meter 5 Then the coupling of the phase detector 7 to the controlled generator 6 is activated capture component with

ball frequency and automatic tracking of it, which is controlled by the deviation of the display device.

Auto tracking is provided as follows.

With

f f - f pc - g w

where "C - intermediate frequency;

f g is the frequency of the controlled oscillator;

f | j, is the instantaneous value of the ball rotation frequency, i.e., e, when the intermediate frequency filter is fine-tuned. to a differential combination of the frequencies of the input signals of the mixer, the filter does not change the phase of the signal. When the deviation of the difference frequency (f g -). caused by the fluctuation of the frequency of the ball component f, from the frequency setting of the intermediate frequency filter f, to one side or the other at the output of the intermediate frequency filter, the phase of the signal undergoes corresponding changes, and the phase detector, comparing the phases of the signal at the input and output of the intermediate frequency filter, forms control The voltage that tunes the controlled oscillator, t, e, changes its frequency in accordance with the change of the ball frequency. The tracking of the informative component is carried out in the device with a static error, but the law of variation of the control voltage of the generator with sufficient accuracy repeats the law of variation of the frequency of the informative component,

The phase-shifting chain, which provides the initial phase shift of 90 ° for normal operation of the phase detector, is structurally included in the phase detector. The amplitude of the control voltage produced by the phase detector varies in accordance with the fluctuations of the instantaneous frequency of the ball frequency, t, e, contains a constant and variable component. This voltage from the output of the phase detector goes to the measuring converter of the rms voltage on the input of which is divided by a separator capacitor 9 for excluding a constant component from the signal. At the output of the measuring transducer there is a indicating device that shows the magnitude of the fluctuations of the instantaneous

 one

the frequency of the ball component, i.e. uneven rotation of the balls and separator.

When the state of the ball bearings deteriorates, the unevenness of the rotation of the balls increases, which leads to an increase in the readings of the indicating device. The frequency meter can additionally control the averaged frequency of rotation of the balls. The measurement is performed on a certain mode of operation of the electric machine, i.e. at a certain frequency of rotation of the rotor, which is determined by the electrical circuit of the machine (including the power source) and its load.

At the same time, sources for the power supply of the machine should be used whose electromotive force does not contain harmonics with a frequency of 764194

running in the passband of the notch filter and close to the frequency of rotation of the balls. For a DC machine, for example, a battery can be used, and for an AC machine, a high-power network can be used. When checking the bearings of the generators, the engines that have a close (with a difference of up to 15%) ball frequency value should not be included in the circuit.

The fluctuation of the ball frequency occurs at an early stage of deterioration of the operation of ball bearings, when slippage does not occur on all the balls. It is also caused by separating nests. Therefore, the measurement of the fluctuation of the ball frequency makes it possible to detect a deterioration

0 bearings work at an early stage, which increases the accuracy of control.

Claims (1)

ELECTRIC MACHINE BALL BEARING CONTROL DEVICE, containing an electric circuit connected to the terminals of the machine with a current ripple sensor, a notch filter and a frequency meter connected in series with it, characterized in that, in order to improve the control accuracy, a phase detector, a controlled generator, an intermediate frequency filter are introduced into it , rms voltage meter, capacitor and mixer, the first input of which is connected to the output of the notch filter, the output is the first input of the phase detector the switch and the input of the intermediate frequency filter, the output of which is connected to the second input of the phase detector, the output of which is connected via the capacitor to the input of the rms voltage meter and directly to the input of the controlled generator, the output of which is connected to the frequency meter and the second input of the mixer. SU, „, 1176419