A Comparative Analysis of Two Winding Distribution Approaches for Fault Simulations of Induction Motors

To extract the small fault signatures in motor current signals, the impact of different winding distribution approaches is explored based on simulation and experiment for typical rotor faults such as broken rotor bar (BRB) in induction motors (IMs). The research focus is on the comparison of current responses obtained from two common methods: the trapezoidal and sinusoidal winding distributions. They are realised using the multiple coupled circuit (MCC) models which are deemed to be efficient and accurate. The simulation results from a 4-pole 4 kW AC motor confirms that both approaches can adequately simulate the twice slip characteristic frequency components around the supply frequency under BRB fault conditions. Moreover, the trapezoidal winding distribution approach can also yield features in the higher frequency range, allowing rotor bar pass frequency components and BRB frequency components to be simulated. In particular, the BRB components also presents them as the sidebands of the rotor frequency modulating with supply frequency. Through experimental testing, it confirmed that the trapezoidal winding distribution approach provides a more accurate reflection of the stator current characteristics under BRB fault conditions. This finding has demonstrated the viability of the trapezoidal distribution method as a potent approach for enhancing the diagnosis and detection of not only BRB but also rotor eccentricity and bearing deterioration by including the high frequency information inside current signatures.