Application of Transient Analysis to Detect Rotor and Stator Asymmetries in Wound Rotor Induction Motors: a Field Case

Abstract

The analysis of motor currents under starting has proven to be a powerful method for enhancing the reliability of the diagnosis of several electromechanical failures in induction motors. Among other advantages, it enables to avoid false indications of conventional methods and, the same time, it provides a robust diagnosis regardless of the operating conditions or of the constructive characteristics of the machine. In particular, the method has proven its usefulness to detect rotor asymmetries, not only in cage motors (CM) but also in wound rotor induction motors (WRIM), in which this type of faults are more frequent. Nowadays, several research lines are oriented toward studying the extrapolation of this methodology for the detection of other types of faults. The present paper expands the applicability of the method to detect stator asymmetries in WRIM. This is done by using a field motor case, in which the application of the transient-based method enabled to detect the presence of certain levels of asymmetry both in the rotor and in the stator winding. The timely detection of this anomaly, thanks to the application of these methods, enabled to avoid a potential outage of the field WRIM with subsequent catastrophic consequences.