Early Intervention: Impulse Testing and Turn Insulation Deterioration in Electric Motors

This paper presents very expensive impulse testing (also called surge testing) and turn insulation deterioration in electric motors. The tests include multiple start and stops under normal line conditions. The stresses introduced into the winding during startup and stopping process were two-fold. These stresses were the cause of the shorted turn-turn. The insulation failure mechanisms, fundamentals of impulse testing and results of various tests are presented.