Method for automatic assessment of electric motor condition before its startup

Abstract

A new method for identification of defects in winding insulation of switched off electric motors connected by a cable to a power source. To assess condition of a motor, rectangular voltage pulse is applied to one of motor connection phases. Mathematical simulation and experimental studies of motors with defects have shown that AC voltage between phases emerges at the subsequent discharge of interphase capacitances. Frequency of such voltage is a function of defect and location of its origin. This method can be applied for three phase motors of all transport vehicles and industrial plants motors, which are cable jointed.