Influence of rotor faults on induction motor stator current concordia patterns

It is not uncommon for induction motor to develop various faults in rotor during its operating life. It is important to develop methods to identify these faults in their early stages to enable timely preventive maintenance. Fitting sensor in the rotor to detect such faults being intricate and costly, amore realizable and hence popular method for rotor fault diagnoses is by processing and analyzing the stator current signal. The present work attempts to utilize current Concordia patterns obtained using Park's Transformation of stator line current signals for analyzing different rotor faults in an induction motor. Hardware experiments have been performed on an induction motor with various rotor faults as pointed out earlier. Each fault was studied under varying degree of load level to obtain more realistic results. Shape, size, and inclination of Concordia patterns thus obtained are found to have clear influences of the type of corresponding rotor fault and degree of load level.