Motor current signature analysis during accelerated life testing of form wound induction motors

The work presented in this paper describes motor accelerated thermo-mechanical aging and helps set the stage for on-line monitoring/data analysis as an effective means to detect a fault as electrical machine develops it and identify its type in real time. As a first step towards this goal, Motor Current Signature Analysis (MCSA) is applied to the data collected during accelerated thermo-mechanical aging of a formed wound induction motor tested to failure. The characteristic frequencies corresponding to detecting broken bars, stator inter-turn shorts, static/dynamic eccentricities and gradual degradation of the machine insulation are identified and sought from the collected data. To accomplish this accelerated aging, the motor was started/stopped frequently and subjected to overload in a steady state manner to subject it to severe thermo-mechanical stresses. Detailed analysis of experimental data is presented. It is hoped that this effort would pave the way for future work where on-line monitoring and diagnostics become a standard tool for life extension, lower maintenance cost, condition based loading, etc. for electrical assets.