Propagation Characteristics of End-Winding Insulation Fatigue Damage in Variable Frequency Motor Under Multi-Field Coupling

In this paper, the fatigue propagation mechanism of motor stator insulation damage under variable frequency drive is studied by combining theoretical analysis and finite element numerical simulation. Based on the magneto-thermo-solid coupling and fatigue damage theory, the stress-strain state, crack damage degree and propagation rate of motor stator insulation are analyzed. The crack damage propagation at different positions of the end winding outlet, middle and nose end is simulated and calculated by three-dimensional finite element method. It is found that the stress, strain and stress intensity factor of the end winding insulation at the outlet position change violently, which reflects that the crack damage is easier to expand and the propagation rate is greater. The results of this paper can provide reference for the evolution law, fault diagnosis and optimization design of insulation damage of variable frequency drive motor under complex working conditions.