Motor Service Life vs Design Life

Large industrial motors are commonly designed to provide over 20 years of reliable service. Oftentimes, the actual service life is significantly shorter than the design life. When this occurs, end users often associate the decreased life (i.e. the actual service life) as being caused by inferior manufacturing quality a deliberately shortened design life (i.e. motor cost reduced at the expense of designing for long life) without understanding all the aspects that impact the actual service life.This paper will explore the multiple facets that need to be addressed to optimize the actual service life. Environmental conditions, input power (e.g., power quality, operation on a drive, synchronous bus transfer, etc.) and maintenance practices will be discussed within the context of how they impact motor reliability and longevity. In addition, periodic offline testing as well as continuous trending of key performance indicators will be explained to understand how these things can be useful to determine proper maintenance and operating practices which result in maximized service life.