Broken bar detection in single-phase reciprocating compressors

Broken rotor bar detection in induction motors using current signature analysis gives good results when the motor load is almost constant. However, if the load torque is oscillating, or it is a function of the rotor position, the current spectrum will contain spectral components which coincides with the components produced by rotor faults. Thus, rotor fault detection in these loads, such as compressors and other reciprocating loads, is very difficult. A new strategy for broken rotor bar diagnosis in single-phase induction motors is presented in this paper. This strategy is based on the analysis of the auxiliary winding voltage. The proposed strategy allows the diagnostic of rotor faults even with pulsating load torque. Simulation and experimental results are presented.