Electromagnetic field analysis of 3-Phase induction motor drive under broken rotor bar fault condition using FEM

One of the common faults encountered in 3 Phase squirrel-cage induction motors (IM) is broken rotor bar faults which constitutes nearly 7% of all the IM failure. In this work, a study on the electromagnetic characteristics of open-loop pulse width modulated (PWM) inverter fed IM is carried out under healthy condition & broken bar fault condition using Finite Element Method (FEM) analysis. The importance of electromagnetic field analysis is, the electromagnetic field waveform contains the information about the position of stator, rotor and mechanical parameters of IM. Thus the method of monitoring airgap magnetic fields can be used for the diagnosis of faults in IM. Detection of single broken bar is difficult because the significant change in the motor parameters due to the fault is hard to identify. So for the analysis a healthy motor model and a model with one broken bar are created. Comparative analysis of the variation in electromagnetic fields obtained from these two models is done using ANSYS Maxwell Finite Element Analysis software tool.