Experimental study on no-load loss characteristics of alternating current excitation motor

Abstract

The key technical problems of pumped storage alternating current excitation motor engineering in China need to be solved urgently. Herein, the no-load loss characteristic test of the 3MW alternating current excited motor was mainly carried out using the test prototype of the 3MW alternating current excitation motor. Further, with the aid of the finite element method, the numerical study of no-load loss characteristics of a 3MW alternating current excited motor was performed. No-load characteristics, no-load loss characteristics, the relationship between constant loss and voltage unit value, and the variation law of no-load core loss of the motor under different loads are carefully analyzed. The results demonstrate that under no-load condition when the applied voltage is less than the rated voltage, the voltage was proportional to the current. When the applied voltage was more significant than the rated voltage, the current increased with the voltage increase, but the relationship between the two was no longer proportional. The constant loss of the motor maintains a linear relationship with the square of the unit value of the voltage scale. When the square of the unit value of the voltage scale was zero, the loss was equivalent to the wind friction loss under no load. Core loss increases with the increase of load, and the greater the load, the faster the increase rate of the motor iron loss. The comparison deviation between the test and simulation results was less than 10%. The simulation and experimental results verify the effectiveness of the finite element modeling and finite element calculation method.