Condition Monitoring of Permanent Magnet Synchronous Motor under Different Stator Fault Severity

Stator fault accounts for almost 40% in motor faults, and inter-turn short fault is regarded as the primary cause for the fault. To detect the inter-turn insulation fault, this paper uses the three-phase current unbalance degree as the fault indicator to monitor motor condition in real-time. Firstly, the fault characteristic is calculated, and then the implementation of the fault diagnosis algorithm is introduced through a step-by-step procedure. Furthermore, experimental results from a 400W permanent magnet synchronous motor are shown before and after the stator inter-turn fault occurs. Moreover, the fault characteristic at various stator fault severities under different number of shorting turns and connection resistances are demonstrated, which indicates that the current unbalance is an importance parameter to realize the stator fault online monitoring and diagnosis.