Mark your calendar for March 9, 2015. The United States Department of Energy issued a Final Rule in March of 2010 mandating energy efficiency levels be increased – effective March 9, 2015. The rule affects a very specific range of motors which include NEMA two-digit frame motors and IEC equivalents for Open Drip Proof, General Purpose motors in both single and three phase designs. Dubbed the Small Motor Rule, horsepower ratings covered include 0.25 thru 3 HP (and kW equivalents) with speed ranges of 1,200 – 3,600 RPM operating from 60 Hz frequency.

What is considered as “General Purpose"?

The rule was interpreted using information found in the National Electrical Manufacturers Association (NEMA) standards book – NEMA MG1-1987. The characteristics used to define General Purpose motors are:

• Built with open construction
• Rated for continuous duty
• Service factor
• Insulation system
• Designed in standard ratings (i.e. horsepower or kilowatt)
• Standard operating characteristics
• Standard mechanical construction
• Designed for use under usual service conditions
• Not restricted to a particular application

There are very specific conditions for electrical and mechanical design of the motor. The motor enclosure type covered under the Small Motor Rule is limited to Open Drip Proof construction. Open air-over designs are not covered.

The ruling requires motor manufacturers to cease production of all motors that are not covered under the new rule. However, motors built and inventory prior to March 9, 2015 can be sold and installed.

Download: Small Motor Rule White Paper