Keywords: squirrel–cage induction motors, finite element analysis, FEA, broken rotor bars, force calculations, modelling, motor speed, motor torque, mechanical stresses, rotor shaft
Analysis and force calculations for induction motors with broken bars using ABC frame model combined with 2D finite element method
In this paper, an ABC transient model of the three–phase induction motor is developed that depends on self and mutual inductance calculations based on accurate finite element analysis (FEA). This model can represent both healthy and faulty motor conditions. The rotor broken bars faults are studied thoroughly including their effects on the rotor bar currents distribution, the forces exerted on the rotor bars, the motor speed and motor torque. It was observed that broken bar faults will cause fluctuations in the motor speed and torque. It was found that the non–uniform distribution of the rotor bar currents will lead to non–uniform radial forces affecting the bars. This will increase the mechanical stresses on the rotor shaft.