Load Torque Signature Analysis: An alternative to MCSA to detect faults in motor driven loads

In this paper, an alternative to the MCSA (Motor Current Signature Analysis) method to detect faults in motor driven loads is presented. The proposed method named Load Torque Signature Analysis - LTSA - processes an estimative of the load torque to obtain a signature of the fault on the load. A comparison of the LTSA and MCSA method is done under the viewpoint of frequency bandwidth, sensitivity and implementation drawbacks. The influence of electrical and mechanical parameters on LTSA performance is investigated. Mathematical relationships among these parameters which allow establishing the nature of the frequency response are obtained. It is shown that, LTSA can be an interesting alternative to be applied in several situations where MCSA performance is poor. Simulation and Experimental results validating the studies are presented.