Review of the DOE Final Rule for Integral Horsepower Motors

At the end of May 2014, the U.S. Department of Energy (DOE) released the Final Rule that amends the regulation for integral horsepower motors. Until the rule takes effect June 1, 2016, motor manufacturers will continue to operate under rules from the Energy Independence and Security Act (EISA), which took effect in December 2010. This means that almost all low-voltage, three-phase motors sold for use in the U.S. will need to be premium efficiency per National Electrical Manufacturers Association (NEMA) MG 1-2014, tables 12-12 and 20B. Additionally, 56-frame enclosed motors, including those with 56J pump mounting, are covered. Motors with close-coupled pump mounting in JM, JP and West-Coast configurations will now move from energy efficiency (table 12-11) to premium efficient levels. All types of vertical hollow-shaft and solid shaft P-base motors also will be required to be premium efficiency. Only submersible motors will be exempt.

Product Utility

The DOE studies product utility when evaluating changes to regulated products. They determine if the new motor will have the same form, fit and function as the motor currently being used. In other words, does the motor have the same mounting footprint, speed and torque characteristics so that it can be used on existing older equipment without modification? In this case, the answer is "not completely." Original equipment manufacturers (OEMs) are encouraged to work with their motor suppliers and source samples to be ready for production conversion when non-compliant motors are discontinued from manufacture next year. Because these higher efficiency motors have less slip, their higher speed may require some changes to the impellers to adjust pump flow and prevent motor overload. Motors with higher efficiency usually require additional active material, including steel laminations and copper windings. Enclosed 56-frame motors were not regulated for efficiency prior to this rule, so they will be going from exempt efficiency levels to the premium level. Most 56-frame motors use a rolled-steel band for the frame, so they are likely to get longer and, in some designs, larger in diameter. Many integral horsepower open motors may also use rolled-steel frames, which increase in length as active material is added. Cast-iron enclosed or open frames usually are made with one length per frame size, so the additional active material is added inside that frame until it reaches a limit. Additional material means more cost.

Small Motor Rule

The DOE issued a Small Motor Rule in 2010, which took effect March 9 of this year. This rule covers 42-, 48- and 56-frame, single- and three-phase 60 Hertz (Hz) general-purpose motors in open drip-proof (ODP) enclosures rated at 1/4 through 3 horsepower (HP). This means motors with 56J and pool pump mountings are not included, but standard base mounted and C-face designs are. Enclosed designs and customized ODP motors are not covered under the Small Motor Rule. At press time, a working group that will review future changes to the Small Motor Rule is being organized. The next rule will likely be more encompassing and may be designed to reduce confusion with the rules on integral horsepower motors.

Conclusion

The DOE has chosen to regulate pump, fan and compressor systems. This extended product approach covers the motor and driven load, including any power transmission devices or adjustable speed drives that are used. The coming years will require the pump industry to adapt and end users to understand and work with these new regulations. The U.S. has lower energy costs than Europe and does not currently have a carbon tax. If the nation's energy costs increase and states begin to add carbon taxes, the industry will need to evaluate old inefficient extended product systems and replace them with higher efficiency solutions. Utilities are likely to incentivize such conversions as they have in the past. The American Council for an Energy Efficient Economy (ACEEE) is organizing an Extended Motor Product Label Initiative (EMPLI) that will offer incentives based on using the DOE extended product rules as a baseline. Products above the baseline would be eligible for an incentive from the utility program based on deemed savings. The pump industry can expect to see a lot of activity surrounded energy efficiency, and OEMs and end users should stay informed about ongoing changes .