Design Alone is Insufficient to Meet API 541 5th Edition Requirements for Reliability

The Fifth Edition of API 541 [2] extended the uninterrupted continuous operation of motors covered by the specification from 3 years to 5 years and the service life of machines from 20 years to 25 years. The specification recognizes that uninterrupted operation for this time period involves factors beyond the vendor's control. This paper provides design, manufacturing, application, and monitoring aspects that will assist the end user in achieving these new service condition requirements. This paper discusses the importance of lubrication, ways to maintain low vibration levels from startup and during operation, accessories to protect vital machine components, selection of the proper enclosure for the application, stator winding connections, and proper use of space heaters in the field.