Induction machine current space vector features to effectively discern and quantify rotor faults and external torque ripple

Intensive research efforts have been spent with the aim of separating the effects of load torque unbalance from those of rotor faults in induction machines. Recent literature reports that active and reactive components of the current space vector seem to show different features in correspondence of the two fault events. This study shows the angular displacement of the above components is fundamental in order to distinguish external torque ripple from rotor faults. The fault severity and the external torque ripple can also be effectively determined. Moreover, the proposed technique allows to assess the range of validity of the usual motor current signature analysis (MCSA), based on the sum of the amplitude of stator current sidebands, for quantifying rotor bar faults