Engineers: Restart your motor specifications
Federal minimum standards for nominal full-load motor efficiencies take effect for motors manufactured after Dec. 19, 2010.
By Michael Ivanovich, Editor-in-Chief, and John Malinowski, Baldor Electric Co.,
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The minimum efficiency of many types of motors between 1 and 200 hp will increase to National Electrical Manufacturers Assn. (NEMA) Premium levels for motors manufactured after Dec. 19, 2010. The Energy Independence and Security Act of 2007 (P.L. 110-140), known as EISA, affects the nominal full-load efficiencies of many types of electric motors in commercial and industrial service. Other EISA measures increased the Corporate Average Fuel Economy (CAFÉ) for automobiles and promulgated efficiency standards for public buildings, some equipment, and appliances.
EISA took aim at motors because from mining to air movement, motors account for nearly 50% of total U.S. energy use and two-thirds of all electrical energy used in industrial settings. Even small increases in motor efficiency could lead to large energy savings over the lifetime of the motors.
EISA is aimed at manufacturers. Beginning Dec. 19, manufacturers cannot make general purpose motors of 1 to 200 hp at less than NEMA Premium efficiency for use in the United States. Motors made prior to that date can still be sold and installed. EISA is applicable for motors constructed and shipped individually or as components within equipment.
To comply with EISA, engineers need to check their specifications to ensure that the new minimum motor efficiencies are brought up to date for fans, pumps, cooling towers, chillers, etc.
Applicability
Only the motors specified in EISA are covered by this new rule, and only if they are to be used in the United States or are purchased by the federal government. Table 1 summarizes the specification language in EISA. For complete wording, download a PDF of the entire act at ow.ly/ZUmO and skip to Section 313, which is on page 77.
What does this mean for engineers?
NEMA Premium motors use more copper and steel than their less-efficient counterparts, so they are a little larger and weigh more. Thus, they will have higher first costs and higher shipping costs. For motors shipped from China and other foreign countries, shipping costs limit the affordability or availability of some motors.
Furthermore, the additional size and weight may require a review of handling and installation procedures. Obviously, the larger the motor, the larger the impact. Designers and specifiers will have to review their standard drawings and specifications to account for new dimensions and weights, and project managers should expect higher first costs.
Any equipment that uses an applicable motor could be affected, including fans, pumps, chillers, cooling towers, packaged systems, and air handlers. Operating costs for electricity should, however, decrease in proportion to the operating hours of the motor.
Rebates for Premium efficiency motors may be available, depending on the project and its location. To find applicable rebates, search the DSIRE database at www.dsireusa.org . The DSIRE database is maintained by North Carolina State University and covers renewable energy and energy efficiency.
Table 1 : EISA provisions by motor type from Section 313
EISA Subparagraph | Type | Subtype | Size | NEMA spec |
(A) | General purpose | I | 1 - 200 hp | NEMA MG%%MDASSML%%1 (2006) Table 12%%MDASSML%%12 |
(B) | Fire pump motors | NEMA MG%%MDASSML%%1 (2006) Table 12%%MDASSML%%11 | ||
(C) | General purpose | II | 1 - 200 hp | NEMA MG%%MDASSML%%1 (2006) Table 12%%MDASSML%%11 |
(D) | NEMA Design B | General purpose | 200 - 500 hp | NEMA MG%%MDASSML%%1 (2006) Table 12%%MDASSML%%11 |
Note: Subtype 1 is defined in EISA by “Energy Efficiency Program for Certain Commercial and Industrial Equipment: Test Procedures, Labeling, and Certification Requirements for Electric Motors” (10 CFR 431). Title 10 (i.e., Energy) of the Code of Federal Regulations (CFR), Subpart B Electric Motors has exact motor definitions, testing specifications for how efficiency is rated, and labeling requirements. You can find the full text on the Electronic Code of Federal Regulations Web site at ow.ly/ZTAw . | ||||
Subtype 2 is defined in EISA as Subtype I motors that are configured as one of the following: | ||||
(i) | A U-frame motor. | |||
(ii) | A design C motor. | |||
(iii) | A close-coupled pump motor. | |||
(iv) | A footless motor. | |||
(v) | A vertical solid shaft normal thrust motor (as tested in a horizontal configuration). | |||
(vi) | An 8-pole motor (900 rpm). | |||
(vii) | A poly-phase motor with voltage of not more than 600 V (other than 230 or 460 V). | |||
Author Information |
Ivanovich has been the editor-in-chief of Consulting-Specifying Engineer since 2007. Prior to that, he was the chief editor of HPAC Engineering and a senior research scientist for Pacific Northwest National Laboratory. Malinowski is the ac motor product manager for Baldor Electric Co., a senior member of the Institute of Electrical and Electronics Engineers (IEEE), and a member of the IEEE Industry Applications Society. |
AT A GLANCE
Other resources
• “Understanding the Efficiency of Motors,” by J. Malinowski and G. Weihrauch , HPAC Engineering, February 2010, ow.ly/ZU59
•“Efficiency Incentives: Driving Toward Enhanced Motor Efficiency,” by Mark Jewell, Engineered Systems , November 2009, ow.ly/ZU29
• “How EISA Will Affect Your Motor Policy,” by CDA, ow.ly/ZTSK
• PDF of NEMA Table 12-11, Product Scope and Nominal Efficiency Levels, ow.ly/ZUcf
• ACEEE Web site page on motors, www.aceee.org/Motors/index.htm
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