A new method to separate broken rotor failures and low frequency load oscillations in three-phase induction motor

Abstract

For a time-varying loads, the presence of load fluctuation may sometimes have the same effect as broken rotor failure in a stator current of induction motors. In recent years, many methods, which are used to distinguish these two effects, have been published. In this study, a new method, which is based on Analytical Signal Angular Fluctuation (ASAF) signal, is developed to separate effects of load oscillation from broken rotor bar, especially when load oscillation is close to twice slip frequency. The simulation results are presented for the proposed method to show that, discerning broken rotor bar faults from low frequency load oscillation is possible. The developed method is independent of motor parameters.