Graphical investigation of the induction motor rotor cage currents under faulty operation

The paper is aimed at an investigation of the effects of different faulty scenarios on the induction motor (IM) operation with emphasis on the currents in the rotor bars and end rings. To do so, the modeling of the IM followed by a graphical representation-based analysis of the rotor steady-state currents is treated in a first step. Then, a case study is considered in order to investigate the faulty operation of the IM with a focus on the rotor cage currents. It has been found that the rotor faults greatly affect the currents in the bars and in the end rings both in amplitude and in harmonic content. These vary according to the relative positions with respect to the fault such that: (i) the currents in the bars adjacent to the faulty one(s) have the highest amplitudes with the lowest harmonic content, and (ii) the ones in the ring portions adjacent to the faulty one have the lowest amplitudes with the highest harmonic content.