中文摘要：

变频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。为此,针对JD117变频电机匝间绝缘用电磁线进行试验研究,以绞线对为试验对象,在双极性高频脉冲电压下,进行了不同频率和不同时间的老化,测试并分析了试样的介电频率谱和温度谱,结合扫描电镜（SEM）研究了不同老化条件对绞线对表面形貌的影响。试验结果表明：随着老化程度的加深,通过分析tanδ的频率谱,其峰值点的数值可以被用来判断绝缘的老化状况。老化使得材料内部结构发生变化,长链发生断裂,生成了小分子量的极性分子,松弛极化更易建立。老化前后,绞线对表面的形貌有很大的不同并且差异随着老化程度的加深而加大。

英文摘要：

The failure of enameled wire used in inter-turn insulation of inverter-fed motor winding is the main reason leading to the motor insulation breakdown. The enameled wire used in inter-turn insulation of JD117 inverter-fed motor was experimentally researched by focusing on twisted pairs as test object. Bipolar pulse voltage aging test was conducted under various frequency and time,and dielectric frequency and temperature spectra of specimen were measured and analyzed.Moreover,combining with scanning electrical microscope （SEM）,the influence of different aging conditions on surface morphology was researched. The experiment results reveal that with the deepening of aging degree,through analyzing frequency spectrum of tanδ,its peak value can be used to judge the insulation condition. Aging will change the structure of material internal,for long-chains are fractured leading to the formation of polar molecules with low molecular weight,therefore,relaxation polarization is more easy to be established. The more severe the aging is,the more material internal defects are created resulting in the easier formation of defective polar particles and greatly increasing dielectric loss. There exists significant difference of surface morphology of twisted pair between non-aging and aging,and the difference becomes increasingly evident with the deepening of aging degree.