关键词: 匝间短路, 绝缘故障, 电痕放电, 防水防潮

Abstract: To solve the turn-to-turn insulation fault of a certain type of traction motor, the mechanism and inducing factors of electrical tracking discharge were investigated by means of physical object verification experiments. The results show that the electrical tracking discharge phenomenon occurs when conductive contaminants exist between two turns of the winding,the turn-to-turn voltage reaches 230 V and maintains for 10 s continuously. It is confirmed that the critical conditions for turn-to-turn insulation failure induced by electrical tracking discharge include the presence of insulation
defects on both turns of the winding,the adhesion of conductive contaminants on the insulation surface,the application of sufficient voltage amplitude between turns,and the sustained duration of electrical tracking discharge. Based on the above research conclusions, water immersion insulation screening was carried out for this type of traction motor, with the unqualified rate detected to be 0. 49%, which is basically consistent with the actual failure rate of turn-to-turn insulation fault of the motor. After the adoption of the improved process measures of anhydrous cleaning combined with secondary varnish impregnation,the same type of turn-to-turn insulation fault of this traction motor has been completely eliminated and no similar failure cases have occurred again.

Key words: turn-to-turn short circuit, insulation fault, electrical tracking discharge, waterproof and moisture-proof