FEM based Assessment of Winding Inter-Tum Fault Indicators in Line Connected Induction Motors

The paper aims at the definition of proper indicators for the effective detection of stator inter-turn faults in line connected induction motors. The procedure uses a finite element model related to a standard medium rated motor, tuned taking into account both magnetic saturation and the actual winding scheme. After the experimental check with reference to different load conditions, multiple fault indicators are evaluated by elaborating the motor current components. The same model predicts the effects of asymmetric voltage supply on the current harmonics to prevent misleading fault detection. Moreover, a relation between fault severity and the experimental setup to reproduce similar current asymmetries as in the actual fault condition has been examined. On this basis, some measurements have been carried out, enabling to have a broad check on the fault indicator effectiveness.