Degradation and Fatigue of Epoxy Impregnated Traction Motors Due to Thermal and Thermal Induced Mechanical Stress: Part I: Thermal Mechanical Simulation of Single Wire due to Evenly Distributed Temperature

The focus of this work is to characterize the mechanical stresses and fatigue along the enameled wire due to thermal expansion. The stresses and fatigue is estimated for a single wire and as a function of evenly distributed temperature. The estimation is based on both analytical equations and 3D Finite Element (FE) model. This characterization of mechanical stresses and fatigue is then used to examine the outcome of the accelerated test based on the measured thermal loads on the motorette specimen. The outcome of this work is not only to detect the cause of insulation failure but also provide useful hints for the traction motor designers.