Influences of a Bar Breakage Evaluated through the Finite Element 3D Model of the Squirrel-cage Induction Motor Start-up

The finite element analysis in time domain of a squirrel-cage induction motor is considered in order to evaluate the influence of a rotor bar breakage fault on the stator current, on the electromagnetic torque, on the rotor unbalanced force and on the magnetic flux density in a point of the motor airgap.Results for healthy and faulty operation states of the motor, based on the 3D model of the no-load motor start-up, for an initial short period of time are obtained and studied.The presence of the bar breakage faults is very well reflected by the rotor unbalanced force and by the magnetic field in the particular point specially chosen for the investigations related the rotor bar breakages.