Many motors are labeled super, top, and premium efficient, but until a couple years ago, there wasn't any quantitative definition of the term. Then in June 2003, National Electrical Manufacturers Association (NEMA) established a consensus definition of “premium efficiency” and outlined the performance criteria motors had to meet to earn that designation. Basically, all NEMA premium-efficiency motors are least 77% efficient, while more powerful varieties are held to higher standards; for example, 60-hp NEMA-premium units must be 95% efficient.
