复杂电磁力作用下10kV交流电机端部绕组绝缘损伤应力强度分析

Stress intensity analysis on insulation damage of 10kV AC motor end winding under complex electromagnetic force

针对10 kV大功率牵引电机端部绕组绝缘层的早期故障问题,基于断裂力学理论分析了绝缘层裂纹损伤在复杂电磁力、机械力作用下的破坏机理。利用有限元方法建立三维分析模型,并通过分段加载电磁力对不同位置的绝缘层裂纹应力应变状态进行数值计算,同时引入应力强度因子对裂纹损伤扩展的程度进行评估。结果表明:与鼻端位置绝缘层裂纹损伤相比,线棒关节处裂纹扩展的速度更快、断裂程度更大;裂纹的初始损伤状态对断裂及扩展程度也有重要影响,横向裂纹更容易扩展。

Aimed at the early fault of 10 kV high power traction motor end winding insulation layer, the failure mechanism of insulation layer crack damage under complex electromagnetic and mechanical forces was analyzed on the basis of fracture mechanics theory. A three-dimensional analysis model was established by using the finite element method, and the stress-strain states of the insulating layer crack at different positions were calculated numerically by piecewise loading electromagnetic force. At the same time, the stress intensity factor was introduced to evaluate the degree of crack damage expansion. The results show that compared with the insulating layer crack damage at the nose end, the crack expansion speed at the rod joint is faster and the fracture degree is greater. The initial damage state of the crack also has an important influence on the fracture and expansion degree, and the transverse crack is easier to expand.