Small Electric Motors
Efficiency Standards History: The Energy Policy and Conservation Act (EPCA) established the energy conservation program for consumer products other than automobiles. Motors one horsepower and larger have been subject to minimum energy efficiency standards since 1999. The Energy Policy Act of 1992 (EPACT 1992) amended EPCA to authorize DOE to prescribe energy conservation standards for small electric motors. The amendment required DOE to prescribe test procedures, and then standards, for those small motors for which DOE determined that standards would be technologically feasible and economically justified and would result in significant energy savings. On July 10, 2006, the Secretary of Energy issued a positive determination, and DOE initiated the development of energy efficiency test procedures and standards for certain small electric motors. DOE published the Framework Document for this rulemaking on its website in July, 2007, and held a public meeting to discuss the analytical framework on September 13, 2007. DOE published a preliminary analysis in December, 2008, and held a public meeting to present these result and solicit feedback on January 30, 2009. DOE then published a Notice of Proposed Rulemaking on November 24, 2009, which was followed by a public meeting on December 17, 2009. The Final Rule was published on March 9, 2010.
DOE published Technical Support Documents at several stages during the rulemaking process, including the preliminary analysis, NOPR, and Final Rule. DOE also published an earlier report, Analysis of Energy Conservation Standards for Small Electric Motors, in June 2003.
A Final Rule describing the DOE test procedures for small electric motors was published on July 7, 2009.
Product Description and Usage: The Energy Policy and Conservation Act (EPCA) defines ‘small electric motor’ as a NEMA (National Electrical Manufacturers Association) general purpose alternating current single-speed induction motor, built in a two-digit frame number series in accordance with NEMA Standards Publication MG1-1987—i.e., open construction motors with NEMA frame sizes 42, 48, and 56, and motors with horsepower ratings ranging from 1/4 to 3 horsepower. These motors operate at 60 hertz (Hz) and have either a single-phase or a polyphase electrical design. EPCA also specifies that standards for small electric motors shall not apply to motors that are components of other covered products or equipment subject to energy efficiency standards.
Single-phase small electric motors are commonly found in products and appliances including pumps, fans, and power tools. Small motors range in capacity from 1/4 horsepower to one horsepower and are available in two-, four-, or six-pole configurations, with the four-pole configuration being the most common.
Polyphase motors are used to drive such equipment as pumps, fans, and compressor cylinders. Those motors in a two-digit NEMA frame size range from 1/4 horsepower to three horsepower, although most are one horsepower or less. Such motors are available in two-pole, four-pole, or six-pole configurations, with the four-pole configuration being the most common.
Efficiency Rating: Standard levels are expressed in terms of average full-load efficiency. Ratings vary by product class, which is determined by motor type, number of poles (motor speed), and horsepower. See the Final Rule for specific ratings.
Equipment Classes: For the determination analysis, DOE separately analyzed the following products as separate classes:
(i) single-phase, capacitor-start, induction-run motors;
(ii) single-phase, capacitor-start, capacitor-run motors; and
(iii) polyphase motors.
Analyses: To support DOE's standards process, the Energy Efficiency Standards (EES) group at LBNL performed the following analyses:
· potential energy savings, price increases, and other impacts,
· consumer life cycle cost impacts,
· product usage, market, and market interactions between different types of motors,
· national energy savings and net present value,
· environmental and utility impacts, and
· analysis of non-regulatory alternatives to standards.
 The standards referenced regulate some motors with a “three-digit frame size” up to 500 horsepower. Frame size determines the dimensions of the physical housing in which the motor is mounted and is defined in NEMA industry standard MG-1. Small motors have two-digit frame sizes and some motors with a power rating of 1 horsepower or larger have a two-digit frame size.