Analysis of Failure and Maintenance Experiences of Large Electrical Motors

摘要

Continuous operation of electrical motors is essential to the function of modernpower, manufacturing, and process plants. In order to focus on electrical motor drives that are critical from the reliability and repair point of view, continuously operating motors larger than 100 kW were studied. The operation time of machines was limited to no more than 15 years. To rank the failures and their causes and effects, the failure and maintenance data were collected on motors used in Finnish industrial and power plant installations. Systematic failure mode and effects analyses (FMEA) of the failures were performed using failure reports as source material. In addition to FMEA, maintenance effects and criticality analysis (MECA) was performed. Computerized data treatment methods for analysis of failure rates, distributions, trends, and repair time distributions were used for selected parts of the data analyzed. The results obtained in the Finnish environmental conditions were compared with the corresponding reliability studies of EPRI and IEEE Motor Reliability Working Group. The type of motor involved in the study was mainly the cage induction motor. In this motor type, the bearing related failures (44%) were the dominant trouble area.