中文摘要：

变频牵引电机定子绝缘用电磁线的失效是导致电机绝缘破坏的主要原因。该文以JD117变频牵引电机绝缘用电磁线为试验对象,进行了电击穿、热击穿和电树枝化击穿试验,结合扫描电镜和能谱分析研究了相应的击穿机制。试验结果表明,击穿点主体都是位于电磁线试样棱角和绝缘接缝处。电击穿过程中,炭化的程度非常大,介质发生了剧烈的化学反应。热击穿过程中,击穿主体外围温度很高,介质碳化严重;击穿主体内部炭化程度相对来说不是很大。发生的反应相对电击穿比较缓慢。电树枝化的击穿时间较长,电磁线试样的寿命为11h,经能谱分析测得铝元素含量最多。

英文摘要：

The failure of magnet wires used in inter-turn insulation of inverter-fed motor winding is the main cause which leads to the motor insulation breakdown. This paper conducted experiment, including electrical breakdown, thermal breakdown and electrical tree breakdown, on magnet wires used in the insulation of JDll7 inverter-fed motor and meanwhile combining with scanning electrical microscope （SEM） and energy spectrum analysis, the corresponding breakdown mechanisms were analyzed. The experiment results reveal that all the breakdown main bodies are located at the pointedness and insulation joint of magnet wires. During the process of electrical breakdown, the carbonization degree is very large and drastic chemical reaction takes place. During the process of thermal breakdown, the temperature of peripheral area of breakdown main body is very high and the carbonization degree is serious and however carbonization degree of inner part of breakdown main body is relatively smaller. The reaction is smaller compared with the electrical breakdown. The electrical tree breakdown time is quite long and the life span of magnet wire is 11 h. It is found that the aluminum occupies the highest content tested by energy spectrum analysis.