Stator Faults Diagnostics in Symmetrical Six-Phase Induction Motors Fed by a Three-Phase System

This paper addresses the diagnostics of inter-turn short-circuit faults in the stator windings of symmetrical six-phase induction motors supplied by an unbalanced voltage three-phase system, or under the occurrence of a single-phasing condition. A new approach based on the analysis of the zero-sequence component of the apparent power is proposed to diagnose the inter-turn short circuit faults, independently of the presence of unbalanced supply voltages or single-phasing conditions. Additionally, the voltage Park's vector modulus, and the analysis of the rms values of the six-phase motor currents are also considered in the proposed technique, to monitor and detect the existence of unbalanced supply voltage conditions and open-circuit faults, respectively. Experimental results prove the effectiveness of the proposed approach in discriminating between all these conditions.