Umudike Journal of Engineering and Technology

Magnetic field simulation of electric motor operation is particularly useful for gaining an insight into their dynamic behaviour and electro-mechanical interaction during fault condition. A suitable model enables motor faults to be simulated and the change in corresponding parameters to be predicted without physical experimentation. This paper presents finite element analysis of a faulty electric motor. The 10.1 Hp squirrel cage motor was simulated and operated under normal healthy operation and faulty operation. A load of 20 Nm was applied at 0.2s while a short-circuit fault between Phase A and Phase B occurred at 0.4s as was observed in the faulty motor. From simulation results, it was observed that simulation of the motor with fault leads into undesirable operation of machine with excessive inrush as well as steady state currents of 101.9328 A. The faulty motor went into generating mode after recording transients of about 1898.6847rpm. In addition it results in to oscillating torque 158.9053Nm, which is highly undesirable. Operation of the loaded motor under healthy condition shows the controlled behaviour of the machine in terms of its inrush current and steady state current, speed build up or torque oscillations. It was revealed that speed buildup, current sequences and harmonic of torque ripples is an indicator for detecting this fault.