SU1762278A1 - Method and device for detecting short-circuited wraps in electric machine winding - Google Patents

Abstract

The invention relates to a control and measuring technique and can be used in devices for quality control of manufacturing windings of electrical machines. The aim of the invention is to increase the sensitivity of determining the location of short-circuited turns. The method consists in that the voltage from the sound generator is applied to the inspected winding and to the X-input of the zero indicator, the value of the specified voltage is set to (0.2-0.3) of the nominal value and the frequency is 4-5 times higher nominal frequency, core measurement The invention relates to measuring and control technology and can be used in devices for quality control of the manufacture of windings of electrical machines. The purpose of the invention is to increase the sensitivity of determining the location of short-circuited turns. The drawing shows a functional diagram of a device implementing the proposed instrumental sensor with a coil is sequentially mounted on the teeth of a test magnetic circuit with a tested winding. Find the location of the short-circuited coil in the test winding by the phase shift of the EMF of the measuring sensor coil relative to the voltage of the sound generator. If the tooth of the magnetic conductor is enclosed by a short-circuited coil, an ellipse is observed on the screen of the null indicator 2, and in the absence of a short-circuited coil of the corresponding tooth, an inclined straight line. By adjusting the null indicator, its corresponding modes are preliminarily set in amplitude and phase angle (with respect to the voltage of the sound generator), and at the same time the possibility of detecting a defect in the winding is checked. A device that implements the proposed method, contains a sound generator, a null indicator with a screen, a measuring sensor containing a core with a coil wound on it, an additional magnetic circuit. identical to the subject with a control winding containing a short-circuit and a closed loop. 2 sp.f-ly. 1 il. The device contains a sound generator 1. a null indicator 2 with a screen 3 as an information display element, a measuring sensor containing a ferromagnetic core 4 with a coil 5 wound around it. The drawing also shows the first magnetic circuit 6 of the electric machine with the winding 7 under test. additional magnetic conductor 8. identical to the subject with the control winding 9 containing the loops S o h x | with

Description

rotary closed coil 10 The first output of the sound generator 1 is connected to the first leads of the subject 7 and the control 9 windings, to the first lead of the X input of the zero indicator 2. The second lead of the sound generator 1 is connected to the second leads of the test 7 and control 9 windings, as well as to the second the output of the X input of the zero-indicator 2, the conclusions of the coil 5 of the measuring sensor connected to the terminals of the Y-input of the zero indicator,

The device that implements the method works as follows.

Previously, in order to tune the device and select the optimum mode, the voltage is applied to the test winding 9 of the additional magnetic core 8 and to the input X of the null indicator 2. The voltage of this voltage is set to (0.2-0.3) of the nominal value and frequency 4-5 times higher than the nominal frequency. The core 4 of the measuring sensor is installed on the tooth of the magnetic circuit 8 with a winding 9 that is not covered by a short-circuited coil 10. The induced electromotive force in the coil 5 of the measuring sensor is fed to the Y-zero-indicator input 2. By adjusting the phase angle and the amplitude of the emf by means of corresponding regulators included into the null indicator 2, on the screen 3, images of an inclined straight line are obtained, which indicates the equality of the amplitudes and phase angles of the EMF in the coil 5 and the voltage of the sound generator 1. This completes the first stage, during which the operability of the device is checked and the corresponding voltage and frequency parameters are set.

A second stage follows, during which the possibility of detecting short-circuited turns is checked. For this purpose, the core 4 of the measuring sensor is mounted on the tooth of the magnetic circuit 8, covered by the short-circuited coil 10. At the same time, an ellipse should be observed on the screen 3 of the null indicator 2.

Finally, at the third stage, the location of the short-circuited coil in the tested winding 7 is determined by the phase shift of the EMF of the coil 5 of the measuring sensor relative to the voltage of the sound generator 1. For this purpose, the voltage from the generator to the checked winding is applied, the core 4 of the measuring sensor is sequentially mounted on the teeth the magnetic conductor b with the tested winding 7; Moreover, if the tooth is covered by a short-circuited coil, an ellipse is observed on the screen of the null indicator 2, and in the absence of a short-circuited turn, tine - inclined right.

The invention makes it possible to increase the sensitivity of the method, as a result of which it is possible to detect one short-circuited turn.

Claims (2)

1. A method for detecting short-circuited coils in a winding of an electric machine, in which a magnetic flux in a magnetic core with a checked winding is excited by a voltage from a sound generator, characterized in that. in order to increase the sensitivity of determining the location of short-circuited coils, the voltage from the sound generator is applied to the tested winding and to the control winding with a short-circuited coil a magnetic conductor identical to a magnetic conductor with a tested winding, and on the X input of the null indicator, the value of said voltage is set to (0.2-0.3) of the nominal value and frequency is 4-5 times above the nominal frequency, an induced emf is produced in the measuring coil by mounting its core on a magnetic circuit tooth with a control winding not covered by a short-circuited coil, it is fed through the amplifier to the control plates along the Y axis of the cathode ray tube of the null indicator; its phase angle and amplitude are set by adjusting the same as for the sound voltage the generator, while on the screen of the null indicator there should be an oblique straight line, check the possibility of detecting short-circuited coils by installing a ferromagnetic core of the measuring coil on the magnetic circuit tooth, covered by a short-circuited coil, while on the screen of the null indicator should see an ellipse, then find the location short-circuited coil or turns in the magnetic core with the test winding on the phase shift of the EMF of the measuring coil relative to the voltage of the sound generator At the same time, an ellipse should be observed on the screen of the null-indicator if the corresponding magnetic circuit prong is covered by a short-circuited coil. 2. A device for detecting short-circuited turns in the winding of an electric machine, comprising a sound generator, the first terminal of which is connected to the first output of the tested winding of the test magnetic circuit, characterized in that identical the subject under test has an additional magnetic conductor with a control winding having a short-circuited coil, a null indicator, a measuring sensor in the form of a ferromagnetic core with a coil, the output of the sound generator is connected to the first output of the X input of the null indicator and the first output of the control winding of the additional magnetic circuit, The second output of the sound generator is connected to the second terminals of the tested winding of the first magnetic circuit and the second output of the X input of the zero organ, the first and second terminals of the measuring sensor coil with unified respectively with said first and second input terminals Y-null indicator. 8xU memory. r t /