RU31068U1 - Device for stress testing large asynchronous motors - Google Patents

Description

MKI NO2K 15/00, NO2R9 / 00, G01R31 / 34

LARGE LOAD TEST DEVICE

ASYNCHRONOUS ELECTRIC MOTORS

(Utility model)

The proposed solution relates to the field of electrical engineering, in particular to the testing of large asynchronous electric motors.

For load tests of asynchronous motors, the return operation schemes 1 are widespread. As a rule, they include 5-7 machines, including load machines, each of which is equal or greater in test power. Thus, a solid converter station is required for testing induction motors, and no more than half of the consumed power is returned to the network. Therefore, the natural desire to simplify equipment for load tests and increase their efficiency led to the emergence of mutual load circuits in which the test motor is paired with the same number of poles asynchronous motor operating in the regime of an asynchronous synchronous generator, the phase rotor of which is supplied with an adjustable low frequency voltage . The stators of the test and load machines are connected to a common power source, which covers only losses in these machines.

In 2.3, a complex low-frequency source is presented, consisting of three DC machines connected in a three-phase group and having lined poles excited from the rings of the low-frequency adjuster of the DC machine, six of which beam traverses are connected to the rings and rotate from the auxiliary drive. The speed of rotation of the setter itself is unchanged.

A device for load tests 4, containing the test and load machines, in which a low frequency to the rotor of the load machine is supplied from a collector frequency converter driven by an auxiliary DC motor. The above devices, differing in the method of supplying an adjustable low frequency, contain as a load - asynchronous machine with

phase rotor (dual-power machines) with the same number of poles as the test subject. This complicates the selection of pairs.

The task of creating a utility model is to simplify the selection of pairs for testing.

The problem is achieved due to the fact that in the known device for load testing large asynchronous electric motors containing the test and load machines, power supplies of constant main and adjustable low frequency and a dual-power machine, this dual-power machine is included in the unit: a racing engine, synchronous the generator, while the synchronous generator is connected to the tested machine, the rotor of the dual-power machine is connected to an adjustable low frequency source, and the stator is connected to the load m bus.

The utility model is illustrated in the drawing, which shows a diagram for stress testing.

The device for load tests of large asynchronous electric motors consists of a test engine 1, a load machine 2, an assembly, which includes a racing engine 3, a synchronous generator 4, a dual-power machine 5, and a converter 6. The converter 6 can be of any type, in particular, both in the above analogs and in semiconductors. In the latter case, deviations of the voltage curve of the converter from the sinusoid can be reflected on the load machine 2, but do not affect the test 1. Position 7 indicates the network. The arrows indicate the direction of energy transfer.

The racing engine 3 provides rotation of the unit and covers losses in it, in test 1 and load 2 machines. The generator 4 provides power to the test machine 1 with a sinusoidal voltage that does not depend on the curve shape of the converter 6 and the network 7. The dual-power machine 5 performs several functions: transfers recuperated energy to the unit shaft, provides load machine 2 with reactive energy, sums the frequencies at the output of the load machine 2-fl (l-Sl-S2) and 6-fl (Sl + S2) converter frequencies, equalizing them with unit frequencies

and networks, fl, where S1 and S2 are the slip frequencies of test 1 and load 2 of the machines, respectively.

The device can be used for carrying out load tests of synchronous machines, in this case, direct current is supplied to the rotor clamps of the dual-power machine, adjustable both in magnitude and in direction from two independent sources, from one to clamps AB (not indicated in the drawing) the rotor of the dual-power machine 5, from the other to the CB terminals.

The technical significance of the proposed solution lies in the dry simplification of the selection of the test-load machine pair, in particular, they can both be squirrel-cage or with a phase rotor, and the power of the load machine can be equal to or greater than the power of the test person.

Literature:

1. Gervais G.K. Industrial testing of electrical machines. Energoatomizdat, LO, 1984

2. Sharipov A.M. Methods of loading, determination of heating and additional losses of large AC machines. The dissertation for the degree of candidate of technical sciences. L, 1969, VNII Elektromash

3.Sharipov A.M. Test Method for Large Short-Circuit Asynchronous Motors under Load — In the book: Investigation of electromagnetic fields, parameters, and losses in powerful electric machines, M, Nauka, 1966

4.Levin V.I., Tedliashvili T.A. Scheme of load tests of induction motors. Electrical Engineering, 1974, No. 9.

Claims (1)

A device for load tests of large asynchronous electric motors, containing the test and load machines, power supplies of a constant main and adjustable low frequency and a dual-power machine, characterized in that the dual-power machine is included in the unit: a racing engine, a synchronous generator, while the synchronous generator is connected with the tested machine, the rotor of the dual-power machine with a regulated low frequency source, and the stator with a load machine.