Report of Large Motor Reliability Survey of Industrial and Commercial Installations, Part I

The Power Systems Reliability Subcommittee of the IEEE Industry Applications Society recently initiated a survey of the reliability of large motors in industrial and commercial installations in keeping with its commitment to support or update results of the survey published in 1973 and 1974. Moreover, the new survey has emphasized and expanded on one type of electrical equipment only. The previous survey results were heavily biased by one class of motors in the motor category and contained some results that appeared unreasonable and were considered questionable. The results of this new survey are presented here and intended to expand failure data to additional influencing categories and at the same time be oriented to the more common types in use today. A restriction to a lower limit in size also distinguishes the results to motors in relatively critical applications. A further explanation of the reasons for this survey and intended results is presented in a subcommittee report included for reference in the Appendix.