Introduction to API Standard 541, 4/sup th/ edition-form-wound squirrel cage induction motors-larger than 500 horsepower

API Standard 541 is the premier large induction motor specification, originally created for refining service, but now applied by many companies in a wide range of industries. The 4/sup th/ edition of this Standard has been released, and has many changes and improvements over previous editions. This paper reviews the significant changes relative to the 3/sup rd/ edition. In addition, major specification requirements that distinguish API 541 motors from motors that simply meet NEMA requirements are reviewed as well.