Discriminating rotor cage faults and mechanical load oscillations in three-phase induction motors by the stator instantaneous complex apparent impedance

This paper deals with a new independent parameter diagnostic scheme based on the use of the stator instantaneous complex apparent impedance signature analysis for rotor cage faults diagnosis and their discrimination from mechanical load torque oscillation effects in operating three-phase squirrel cage induction motors. Both simulation and experimental results are presented to demonstrate the effectiveness and the capability of the new proposed approach that offers the possibility to distinguish between the two abnormality conditions by comparing the signature analyses of the real and imaginary parts of the considered quantity for each abnormality condition.