Turn-to-turn insulation failure diagnosis of stator winding of low voltage induction motor with the aid of support vector machine

Turn-to-turn short-circuit of stator winding due to deterioration of electrical insulation is one of the most probable faults in motor drive systems. This paper proposes two diagnostic methods to detect the fault based on Support Vector Machine. In the first method, magnitude and phase of load currents at fixed rotating speeds are considered as features reflecting winding condition. It is found that the method is effective particularly in slight insulation failure like one turn-to-turn short-circuit. Classification of winding condition, i.e. specification of number of short-circuit turns, is also achieved by this method. In the second method, only magnitude of load currents is treated as feature aiming at diagnosis available when load current varies. The method also has the advantage of low cost and short data processing time. It is found that two turn-to-turn short-circuit can be diagnosed with practically acceptable accuracy. An appropriate choice of the two methods should be recommended depending on the goal as well as circumstance of diagnosis.