Impulse Voltage Strength of AC Rotating Machines

The absence of generally accepted standards for the impulse voltage withstand capability of ac rotating machines has led to inconsistency and uncertainty in insulation coordination in systems including these machines. An impulse voltage withstand envelope considered appropriate for ac rotating machines of recent design is presented in this report. The envelope is based principally on the satisfactory field performance of machines in severe transient environments existing in some applications. It is hoped that this material will provide an appropriate and consistent basis for insulation coordination including ac rotating machines.