Erosion Models of Rotor Bar and End Ring Faults in Progress to Diagnose Induction Motor Status

Abstract

Erosion models of rotor bar and end ring segment in induction motors are presented for diagnosing induction machines containing an abnormal rotor bar and end ring faults in progress. The leakage inductance and resistance of the rotor bar and end ring segment are varied during the erosion process. Consequently, the variation causes the rotor asymmetry which induces abnormal harmonics in the stator current spectra. The leakage inductances of the erosion models are derived by the Ampere's law. The winding function method (WFM) is used to conveniently calculate the machine inductance, and the slot width effect (SWE) of rotor bars is concerned more practical motor model. By the erosion models, it is shown that the rotor bar and end ring faults in progress are detectable by the motor current signature analysis (MCSA). Simulated and experimental results are presented to validate the proposed erosion model with 3.7 kW, 3-phase, and squirrel cage induction motors.