Broken bar detection using inverter currents in induction motor drives

Rotor electrical faults are common types of faults in squirrel cage induction motors and have been investigated in detail in steady state condition for grid-connected induction motors. In this paper, this type of fault is studied in case of inverter driven motors. Inverter input and output currents are studied for the fault indicative frequency components. The harmonics which are induced to the inverter input current give the ability of fault detection under low load and low motor severity fault condition in both motor steady-state and transient operation.