Case histories of current signature analysis to detect faults in induction motor drives

This paper will demonstrate through industrial case histories how current signature analysis can reliably diagnose rotor cage problems in induction motor drives. Theoretical advancements have now made it possible to predict rotor disturbances due to gearbox dynamics and mechanical drive train characteristics thus making motor current signature analysis (MCSA) testing much more robust and reliable. Case histories will be presented which demonstrate the ability to separate current components resulting from gearbox dynamics and from those produced by broken rotor bars. From this data, a new handheld instrument for reliable detection of broken rotor bars, air gap eccentricity, shorted turns in LV stator windings, mechanical drive phenomena and certain mechanical problems in induction motor drives is being developed and will be described.