Multiphysics Model for Induction Machine Bearing Fault Diagnosis by Stator Current Analysis

This paper presents a modelling and simulation approach for diagnosing bearing faults in induction motors. Unlike existing magnetic models requiring up to two days of simulation, a simplified dq model is proposed for improved computational efficiency. The electrical model considers the stator windings and rotor loops, while a dynamic rotor-bearing model accounts for displacement variations due to outer race spall defects. These variations influence the air gap length, which is integrated into the electrical model via inductances. An iterative numerical method then simulates the stator current in healthy and faulty conditions. Simulations reveal fault-related spectral components, validated through experimental tests on a dedicated test bench. The agreement between simulated and measured currents confirms the model's accuracy and suitability for fault diagnosis.