NETA World Industry Topics – Testing Rotating Machinery Polarization/Depolarization Current (PDC)


The insulation resistance (IR) and polarization index (PI) tests [IEEE Std. 43-2000, ANSI/NETA ATS/MTS], should be done prior to application of any high voltage tests or return to service to assure that the winding is not wet or dirty enough to pose a risk of failure that might be averted by a cleaning and drying-out procedure.