Detection of Rotor Fault in an Induction Motor Under Standstill Condition – A Power Quality Perspective

The purpose of this paper is to present a study on the power quality issue based on the harmonics present in the air gap flux due to broken bar fault in induction motors. The numerical magnetic field analysis of squirrel cage induction motor based on finite element method is performed to carry out this study. Finite element analysis can be used for predicting the performance of an induction motor having different faults implemented in their structure. Magnetic field is calculated for the case of symmetrical rotor cage and for several cases of rotor electrical asymmetry due to broken rotor bars. The induction motor torque in healthy and faulty condition is also obtained and compared. It shows the relation between the increasing number of broken bars and unproportional distribution of induced rotor currents, which results as a degradation of steady-state and dynamic performance of induction motor. For this study, a squirrel cage induction motor with thirty six stator slots and twenty eight rotor bars has been investigated. This study provides quality assessment of stator and rotor independent of load operating conditions. In this paper, a two-dimensional FEM is performed for modeling and analysis of an Induction motor with broken bar fault using ANSYS software.