Condition monitoring methods, failure identification and analysis for high voltage motors in petrochemical industry

The study gives a synopsis over condition monitoring methods both as a diagnostic tool and as a technique for failure identification in high voltage induction motors in petrochemical industry. New running experience data for 356 units are registered and processed statistically to reveal the connection between motor data, protection and condition monitoring methods, maintenance philosophy and different types of faults. The different types of faults are further analyzed to failure-initiators, contributors and -underlying causes. The results have been compared with those of a previous survey by these authors, and one by an IEEE Report (10). Methods of fault detection are reviewed and analyzed: mechanical (vibrations, shock pulses, acoustic, speed fluctuations), electro mechanical (currents, surges, partial discharges, leakage fluxes) and temperature-, oil particle-, gas analysis, and performance-and visual methods. Different types of faults generates different frequency components in vibration spectra, in motor supply current, in torque and in magnetic field, and relationships between fault types and spectra have been studied.