Insulation diagnosis of motor winding based on feature distributions

Insulation failure of motor windings is one of faults that are likely to occur during the lifetime of motors. The authors have proposed a novel and simple method to diagnose insulation failure in a stator winding in terms of “fault probability”, which is calculated on the basis of feature distributions of magnitude and phase of current flowing into windings. Validity of the method was confirmed under no load condition in the previous report. In this paper, it will be shown that the proposed method is also quite effective under loaded conditions based on the results of a series of laboratory experiments using motors with an artificially introduced insulation failure in a stator winding.