Methods to evaluate the quality of stator and rotor of electric motors

This paper describes some innovative methods for evaluating the design quality and the actual condition of an electric motor. Some techniques discussed below were developed in company with the aim of increasing reliability in the assessment of the stator and/or the rotor of a squirrel cage motor. The methods discussed for stator evaluation involve the measurement of iron losses and the realization of accelerated ageing tests, concerning quality in the design stage of an electric motor. The methods discussed for rotor evaluation involve procedures to check the continuity of the bars and short circuit rings, concerning quality in the manufacturing stage and allowing assessments of the actual condition of the machine in the field.