Standstill Impedance Variation Test For Inverter-fed Induction Motor with Broken Rotor Bar Fault

Most induction motor fault detection techniques such as MCSA that are most effective in the detection of anomalies in grid-connected induction motors fail dismally when applied to inverter-fed induction motors (IMs). This is owing to the injection of additional harmonics, called inverter switching harmonics, into the stator current spectrum of the motor. These additional switching harmonics mask the fault harmonics in the current spectrum of the motor, which complicates the conclusion that there are faults in the motor. Consequently, several detection techniques have been proposed to supplement MCSA. One such technique is the standstill impedance variation test technique used for the detection of broken rotor bar fault in squirrel cage induction (SCI) motors. This paper explores the possibility of the application of this technique in the detection of the broken rotor bar (BRB) fault in inverter-fed IMs utilizing the inverter switching to alter the orientation of the pulsating flux instead of manually changing the rotor position.