Condition monitoring for mechanical faults in fully integrated servo drive systems

A modified motor current signature analysis (MCSA) approach to monitor the performance of a servo drive system using only one set of current transducers at the input side of the rectifier is proposed. The paper introduces a mathematical analysis to determine how the harmonic frequencies related to a fault propagate from the motor to the input inverter, and includes the effect of the DC link components. Experimental results are presented for a permanent magnet servo drive system with faulty bearings to validate the proposed scheme.