SU1420634A1 - Method and apparatus for measuring electromagnetic characteristics of stators of electric machines - Google Patents

Abstract

The invention relates to techno-logic from 1 () comrade, 1 to electrically electic mansion, and can be used in electronic engineering. The purpose of the invention is to improve the accuracy of determining the electromagnetic characteristics. A magnetic core is installed on a calibrated rotor 1 from a three-phase (magnetising 2 and a single-phase measuring 3 windings, included in the measuring circuit, the amplitude of the measured current values in three phases is measured, the magnetising current of the magnetic circuit is determined and the ratio of I and 1 is 1) - L ,.) where .i K () -.ff11ts11ent amnlitudy current of the running path .tektrodvigatel; 1 ,,, 1 1 в and i.,; C amnlitute values of the magnetizing winding current in phases A, B, C; 1. „t is the amplitude value of the magnetizing current of the gated rotor. 2 s. And 1 s. P. f-ly, kl. se (/ С

Description

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about: os

The invention relates to the technology of manufacturing electrical machines and can be used in the electrical industry.

The purpose of the invention is to improve the accuracy of determining the electromagnetic characteristics.

The drawing shows a device for carrying out the proposed method.

The device contains a calibrated rotor 1 with a three-phase magnetizing winding 2 and a single-phase measuring winding 3, to the terminals of which a medium-voltmeter 4 is connected and a current indicator 5 of the magnetizing winding 2, and the current indicator 5 contains three single-phase current converters 6, a voltmeter 7 DC with a large input impedance and switching device (not shown in the drawing) with one m. closing contact 8 and three opening contacts 9. Each converter 6 contains a current transformer 10, two resistors 11 and 12, the rectifier 13 and the capacitor 14, the primary winding of each current transformer 10 is connected in series with one of the phases of the magnetizing winding 2, a resistor 11 is connected to the terminals of its secondary winding, in parallel with which the rectifier 13 is connected to the capacitor 14, parallel to the capacitor 14 through one of the switching contacts 9 of the switching device is connected to the second resistor 12, the capacitors 14 of all current converters 6 are connected in series to the circuit, the ends of which are connected through the closing contact 8 of the switching appr rata to the voltmeter 7 d.c. with bolschoy input impedance.

The diagram also shows wattmeters 15, designed to measure losses in the magnetic circuit, and a three-phase measuring winding 16 for supplying voltage circuits to wattmeters 15.

In the initial position, the measured stator magnet conductor is placed on a calibrated rotor 1, and the leads of the measuring circuit are disconnected from the regulated power source.

To determine the electromagnetic characteristics of the magnetic circuit, the circuit leads are connected to a regulating power source and smoothly increase the voltage of the power source until the average average voltmeter indicates a predetermined voltage corresponding to the flow of the nominal magnetic flux.

Using the switching device, contacts 9 are opened, after which contact 8 is closed after a delay of about 1 s.

When contacts 9 are opened, additional charging of capacitors 14 occurs to a voltage equal to the amplitude of the voltage drop on the corresponding resistors 11, since in this mode the current through the rectifier becomes zero and the voltage drop on the rectifiers is excluded.

With the closure of the contact 8 to the circuit of series-connected capacitors

14, a DC voltmeter 7 is connected and its readings are recorded. At the same time, the readings of the wattmeters are recorded. According to the readings of the voltmeter 7, the sum of the amplitude values is determined

currents in the three phases of the measuring circuit according to the formula

 that

+ + W

R ,,

(one)

where and, the indication of a voltmeter 7, V;

RII resistance of resistors 11, Ohm; K - transformation ratio of current transformers.

Substituted the sum of the amplitude values of the Institute of currents, calculated by the formula (1), into the formula

t L cbpA + ImS + biCI / 9

I Kad (3 W;, ()

The magnetizing current of the magnetic circuit, which is its electromagnetic characteristic, is determined. Kad - the coefficient of the amplitude of the no-load current of the engine - determined by typical engine tests as the ratio of the amplitude of the current

to its effective value. For the majority of electric motors, this coefficient can be taken equal to 1.41. Lt is the amplitude value of the current required to pass the nominal magnetic

the flow of the engine through the magnetic core of the rotor, which is determined during the calibration of the rotor.

Claims (3)

Invention Formula 1- Method for determining the electromagnetic characteristics of the magnetic circuits of the stator of an electric vehicle, including the installation of a magnetic circuit on a calibrated rotor with a three-phase magnetizing and single-phase measuring windings included Measuring the magnitude of the current in the magnetizing winding and determining the magnetisation current of the magnetic circuit, characterized in that, in order to improve the accuracy of determining the electromagnetic characteristics, the magnitudes of the amplitude values of the currents in three phases are measured, and the magnetizing current of the magnetic core is determined from the ratio 1/1-t - 1tib ),   5G ( Jvip where Kad is the amplitude coefficient of the no-load current of the electric motor; 1mA, 1tvi 1, c - amplitude values of the magnetizing winding current in phases A, B, C; 1, „t is the amplitude value of the magnetizing current of the rotor. 2. A device for determining the electromagnetic characteristics of the magnetic circuits of the stators of electric machines, containing a calibrated rotor with a three-phase magnetizing winding and a single-phase measuring winding, to the terminals of which an average voltmeter and an indicator of the magnetizing winding current are connected, in order to improve the accuracy of the determination of electromagnetic characteristics, the current indicator contains three single-phase current transformer, DC voltmeter and switching device with one closing contact and three normally closed contacts, each current converter containing a current transformer, two resistors, a rectifier and a capacitor, the primary winding of each current transformer is connected in series with one of the phases of the magnetizing winding , one of the resistors is connected to the terminals of its secondary winding, in parallel with which a capacitor is connected via a rectifier, parallel to the capacitor one time switching contact snapping on r the second resistor, the capacitors of all current transducers are connected in series to the circuit, the terminals of which are connected via a switching contact of the switching apparatus to a DC voltmeter. 3. The device according to claim 2, characterized in 0 that the DC voltmeter is made in the form of a digital voltmeter.