Case stories of induction motors fault diagnosis based on current analysis

This work presents several case studies related to condition monitoring of induction motors operating in a chemical plant. Analysis of the stator current is applied to diagnose several types of faults, especially rotor damages and mixed eccentricities. The considered current-based techniques include both the conventional method that relies on the analysis of the steady-state current (Motor Current Signature Analysis, MCSA, that will be employed as main tool), as well as recently developed methodologies based on the analysis of transient currents (Advanced Transient Current Signature Analysis, ATCSA, that will be used as complementary tool). The combination of both methods enables to reach a high reliability in the diagnostics, avoiding eventual false indications of a single method. The motors considered in the paper range from small-sized machines till large motors (rated up to several MW). Also, a diversity of operation conditions is considered, including diverse loading conditions as well as different operating options. The results show the powerfulness of current analysis for diagnosing a wide range of failures in asynchronous motors operating in petrochemical plants.