The U.S. efficiency regulations for industrial electric motors have been in place since October 1997 when the Energy Policy Act of 1992 (EPAct 92) set minimum efficiency levels for 1- through 200-horsepower (HP), general purpose three-phase motors. EPAct 92 was upgraded when the Energy Independence and Security Act of 2007 (EISA) went into effect in December 2010, which raised the efficiency level of 1- through 200-HP motors to premium levels and covered other 1- through 200-HP and 201- through 500-HP motors defined in the National Electrical Manufacturer’s Association (NEMA) Standard MG 1-2011 Table 12-11 Energy Efficient Motors. All these regulations cover which motors are allowed to be sold in the U.S. and also covers the motors installed in machinery imported for sale. As has been the normal practice, Canada and Mexico followed with regulations similar to those implemented in the U.S.
Small Motor Rule
Several years ago, the U.S. Department of Energy (DOE) conducted a technical study about how to raise “small” motors’ efficiency levels. After years of study, the Small Motor Rule was passed, covering General Purpose two-digit NEMA frame (and IEC equivalents), single- and three-phase, 1/4- through 3-horsepower motors in open enclosures. Totally enclosed, fan-cooled (TEFC) motors are not included. This regulation will take effect on April 9, 2015. NEMA has written a white paper that provides its interpretation of the rule, which is on its website (www.nema.org).
Although the Small Motor Rule seems simple, it can create motors with much larger footprints, particularly on single-phase designs in which capacitor-start/induction-run motors may be discontinued in open enclosures. In some cases, a TEFC motor, which is not covered by this rule, may be more cost-effective and smaller than an open motor.
Regulations to improve the efficiencies of small motors will take effect on April 9, 2015. The regulations covering medium motors were adopted in May 2014 and will take effect two years.
Integral Horsepower Motor Study
The DOE completed another technical study on integral horsepower alternating current (AC) induction motors of 1 to 500 HP. In its study, the DOE evaluated a possible increase in nominal motor efficiency of 1 to 2 NEMA bands (approximately 0.4 to 1.5 percent) above Premium Efficiency levels as defined in NEMA MG 1-2011 Table 12-12. Although this sounds simple, such a motor redesign may require new laminations; winding equipment; and in many cases, new frames to fit the extra material. Some designs may not fit where existing motor designs of the same ratings fit today. This means that original equipment manufacturers would need to redesign their machine and end users may have trouble retrofitting the new, higher efficiency replacement motor into their equipment or existing envelope.
A petition to adopt NEMA MG 1 Table 12-12 for an expanded scope of 1- to 500-horsepower motors—many that were not previously included by the DOE—was proposed in October 2010 for adoption in place of the DOE’s technical study. This proposal closes many loopholes in previous regulations and should provide easier enforcement and compliance for the DOE.
The petitioners included NEMA Motor Section Members and a group of energy advocate groups with members from American Council for an Energy-Efficient Economy, Alliance to Save Energy, Appliance Standards Awareness Project, Earthjustice, Natural Resources Defense Council, Northwest Energy Efficiency Alliance, Northeast Energy Efficiency Partnerships, and Northwest Power and Conservation Council.
This affects the pump industry because almost all motors will require premium efficient windings. This includes close-coupled pump mountings, custom shafts and endplates, partial motors, and immersible motor designs. Only submersible motors and stator-rotor sets will remain exempt.
The DOE study of integral horsepower motors is complete and the results of the study were discussed in the fall 2012. More interviews with motor manufacturers were conducted in early 2013, and the proposed rule was issued in December 2013. The DOE adopted their proposal as a final rule on May 8, 2014. The new regulations are expected to take effect in 2016, two years after this final rule.