Multiphysics Coupling Model to Characterise the Behaviour of Induction Motors with Eccentricity and Bearing Faults

Bearing faults and eccentricity faults are significant contributors to induction motor performance degradation and failures. This paper presents a multiphysics model for induction motors, integrating both the electromagnetic and mechanical systems to effectively characterise their behaviour in the presence of bearing faults and eccentricity faults. The proposed model incorporates the interactions between the two systems through the unbalanced magnetic pull, the electromagnetic torque, and the rotor motion. Bearing faults are represented as physical spalls with specific width and depth located on the bearing components. Eccentricity faults, on the other hand, are modelled as a non-uniformed distribution of air gap. Both the bearing fault models and the eccentricity fault models are integrated into the mechanical part of the multiphysics model. The model is validated by the comparison with the reference data from the motor manufacturer and the finite element method. Results show the proposed model achieves remarkable accuracy with moderate computational cost. The effects of fault severity, fault location, load torque, and external load on the unbalanced magnetic pull produced in induction motors and the rotor radial displacement are studied.