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Electric Motors

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The Department of Energy (DOE) has regulated the energy efficiency level of electric motors since 1997. Electric motors convert electrical energy to rotating mechanical energy. When operating, the electrical energy is transferred as useful mechanical energy to some driven device such as a fan, pump, blower, compressor, or conveyor.

The Energy Policy and Conservation Act (EPCA), as amended by the Energy Independence and Security Act of 2007 (EISA 2007), covers three broad categories of electric motors: general purpose, definite purpose and special purpose.

These broad categories include a variety of motors including single-speed, continuous-duty polyphase motors with voltages not greater than 600 volts; motors with or without mounting feet; motors built in a T- or U-frame; motors built with synchronous speeds of 3600, 1800, 1200, or 900 rpm (two, four, six, or eight poles, respectively); National Electrical Manufacturers Association (NEMA) Design B motors from 1 to 500 horsepower, NEMA Design A and C motors from 1 to 200 horsepower; and motors that are close-coupled pump or vertical solid-shaft normal thrust motors.

With its most recent final rule, with a compliance date of June 1, 2016, DOE is expanding the regulation and establishes energy conservation standards for a number of different groups of electric motors that DOE has not previously regulated. This amended standard will save approximately 7 quads of energy and result in approximately $41.4 billion in energy bill savings for products shipped from 2016-2045. The standards will avoid about 395 million metric tons of carbon dioxide emissions.


Recent Updates | Standards | Test Procedures | Waiver, Exception, and Exemption Information | Statutory Authority | Historical Information | Contact Information


Recent Updates

DOE published a final rule regarding energy conservation standards for electric motors. 79 FR 30933 (May 29, 2014). For more information, please see the rulemaking page.

DOE published a final rule regarding test procedures for electric motors. 78 FR 75962 (December 13, 2013). For more information, please see the rulemaking page.


Standards for Electric Motors

The following content summarizes the energy conservation standards for medium electric motors. The text is not an official reproduction of the Code of Federal Regulations and should not be used for legal research or citation.

Current Standard

This standard addresses two subtypes of electric motors, as indicated below:

General purpose electric motor (subtype I) means any motor which is designed in standard ratings with either:

  1. Standard operating characteristics and standard mechanical construction for use under usual service conditions, such as those specified in NEMA Standards Publication MG1–1993, paragraph 14.02, "Usual Service Conditions," and without restriction to a particular application or type of application; or
  2. Standard operating characteristics or standard mechanical construction for use under unusual service conditions, such as those specified in NEMA Standards Publication MG1–1993, paragraph 14.03, "Unusual Service Conditions," or for a particular type of application, and which can be used in most general purpose applications.

General purpose electric motor (subtype II) means any motor incorporating the design elements of a general purpose electric motor (subtype I) that are configured as one of the following:

  1. A U-frame motor;
  2. A NEMA Design C motor;
  3. A close-coupled pump motor;
  4. footless motor;
  5. A vertical solid shaft normal thrust motor (as tested in a horizontal configuration);
  6. An 8-pole motor (900 rpm); or
  7. A poly-phase motor with voltage of not more than 600 volts (other than 230 or 460 volts).

Electric motors manufactured (alone or as a component of another piece of equipment), on or after December 19, 2010, and distributed in commerce, as defined by 42 U.S.C. 6291 (16), must meet the energy conservation standards specified in the Code of Federal Regulations, 10 CFR 431.25. This information is also available in the Electronic Code of Federal Regulations.

Table 1. Full-Load Efficiencies for General Purpose Electric Motors [Subtype I]
Motor Horsepower Nominal Full Load Efficiency
Open Motors
(Number of Poles)
Enclosed Motors
(Number of Poles)
6 4 2 6 4 2
1 82.5 85.5 77.0 82.5 85.5 77.0
1.5 86.5 86.5 84.0 87.5 86.5 84.0
2 87.5 86.5 85.5 88.5 86.5 85.5
3 88.5 89.5 85.5 89.5 89.5 86.5
5 89.5 89.5 86.5 89.5 89.5 88.5
7.5 90.2 91.0 88.5 91.0 91.7 89.5
10 91.7 91.7 89.5 91.0 91.7 90.2
15 91.7 93.0 90.2 91.7 92.4 91.0
20 92.4 93.0 91.0 91.7 93.0 91.0
25 93.0 93.6 91.7 93.0 93.6 91.7
30 93.6 94.1 91.7 93.0 93.6 91.7
40 94.1 94.1 92.4 94.1 94.1 92.4
50 94.1 94.5 93.0 94.1 94.5 93.0
60 94.5 95.0 93.6 94.5 95.0 93.6
75 94.5 95.0 93.6 94.5 95.4 93.6
100 95.0 95.4 93.6 95.0 95.4 94.1
125 95.0 95.4 94.1 95.0 95.4 95.0
150 95.4 95.8 94.1 95.8 95.8 95.0
200 95.4 95.8 95.0 95.8 96.2 95.4
Table 2: Full-Load Efficiencies for General Purpose Electric Motors [Subtype II]
Motor Horsepower
Open Motors
(Number of Poles)
Enclosed Motors
(Number of Poles)
8 6 4 2 8 6 4 2
1 74.0 80.0 82.5 - 74.0 80.0 82.5 75.5
1.5 75.5 84.0 84.0 82.5 77.0 85.5 84.0 82.5
2 85.5 85.5 84.0 84.0 82.5 86.5 84.0 84.0
3 86.5 86.5 86.5 84.0 84.0 87.5 87.5 85.5
5 87.5 87.5 87.5 85.5 85.5 87.5 87.5 87.5
7.5 88.5 88.5 88.5 87.5 85.5 89.5 89.5 88.5
10 89.5 90.2 89.5 88.5 88.5 89.5 89.5 89.5
15 89.5 90.2 91.0 89.5 88.5 90.2 91.0 90.2
20 90.2 91.0 91.0 90.2 89.5 90.2 91.0 90.2
25 90.2 91.7 91.7 91.0 89.5 91.7 92.4 91.0
30 91.0 92.4 92.4 91.0 91.0 91.7 92.4 91.0
40 91.0 93.0 93.0 91.7 91.0 93.0 93.0 91.7
50 91.7 93.0 93.0 92.4 91.7 93.0 93.0 92.4
60 92.4 93.6 93.6 93.0 91.7 93.6 93.6 93.0
75 93.6 93.6 94.1 93.0 93.0 93.6 94.1 93.0
100 93.6 94.1 94.1 93.0 93.0 94.1 94.5 93.6
125 93.6 94.1 94.5 93.6 93.6 94.1 94.5 94.5
150 93.6 94.5 95.0 93.6 93.6 95.0 95.0 94.5
200 93.6 94.5 95.0 94.5 94.1 95.0 95.0 95.0
Table 3: Full-Load Efficiencies of NEMA Design B General Purpose Electric Motors
Motor Horsepower
Open Motors
(Number of Poles)
Enclosed Motors
(Number of Poles)
8 6 4 2 8 6 4 2
250 94.5 95.4 95.4 94.5 94.5 95.0 95.0 95.4
300 - 95.4 95.0 - 95.0 95.4 95.4
350 - 95.4 95.4 95.0 - 95.0 95.4 95.4
400 - - 95.4 95.4 - - 95.4 95.4
450 - - 95.8 95.8 - - 95.4 95.4
500 - - 95.8 95.8 - - 95.8 95.4
Table 4: Full-Load Efficiencies of Fire Pump Motors
Motor Horsepower
Open Motors
(Number of Poles)
Enclosed Motors
(Number of Poles)
8 6 4 2 8 6 4 2
1 74.0 80.0 82.5 - 74.0 80.0 82.5 75.5
1.5 75.5 84.0 84.0 82.5 77.0 85.5 84.0 82.5
2 85.5 85.5 84.0 84.0 82.5 86.5 84.0 84.0
3 86.5 86.5 86.5 84.0 84.0 87.5 87.5 85.5
5 87.5 87.5 87.5 85.5 85.5 87.5 87.5 87.5
7.5 88.5 88.5 88.5 87.5 85.5 89.5 89.5 88.5
10 89.5 90.2 89.5 88.5 88.5 89.5 89.5 89.5
15 89.5 90.2 91.0 89.5 88.5 90.2 91.0 90.2
20 90.2 91.0 91.0 90.2 89.5 90.2 91.0 90.2
25 90.2 91.7 91.7 91.0 89.5 91.7 92.4 91.0
30 91.0 92.4 92.4 91.0 91.0 91.7 92.4 91.0
40 91.0 93.0 93.0 91.7 91.0 93.0 93.0 91.7
50 91.7 93.0 93.0 92.4 91.7 93.0 93.0 92.4
60 92.4 93.6 93.6 93.0 91.7 93.6 93.6 93.0
75 93.6 93.6 94.1 93.0 93.0 93.6 94.1 93.0
100 93.6 94.1 94.1 93.0 93.0 94.1 94.5 93.6
125 93.6 94.1 94.5 93.6 93.6 94.1 94.5 94.5
150 93.6 94.5 95.0 93.6 93.6 95.0 95.0 94.5
200 93.6 94.5 95.0 94.5 94.1 95.0 95.0 95.0
250 94.5 95.4 95.4 94.5 94.5 95.0 95.0 95.4
300 - 95.4 95.4 95.0 - 95.0 95.4 95.4
350 - 95.4 95.4 95.0 - 95.0 95.4 95.4
400 - - 95.4 95.4 - - 95.4 95.4
450 - - 95.8 95.8 - - 95.4 95.4
500 - - 95.8 95.8 - - 95.8 95.4

For further guidance or to submit questions related to the implementation of this standard, visit the Guidance and Frequently Asked Questions page.

Amended Standard

This amended standard addresses electric motors, as indicated below:

Electric motors, including partial electric motors, that satisfy the following criteria:

(1) Are single-speed, induction motors;

(2) Are rated for continuous duty (MG 1) operation or for duty type S1 (IEC);

(3) Contain a squirrel-cage (MG 1) or cage (IEC) rotor;

(4) Operate on polyphase alternating current 60-hertz sinusoidal line power;

(5) Are rated 600 volts or less;

(6) Have a 2-, 4-, 6-, or 8-pole configuration,

(7) Are built in a three-digit or four-digit NEMA frame size (or IEC metric equivalent), including those designs between two consecutive NEMA frame sizes (or IEC metric equivalent), or an enclosed 56 NEMA frame size (or IEC metric equivalent),

(8) Produce at least one horsepower (0.746 kW) but not greater than 500 horsepower (373 kW), and

(9) Meet all of the performance requirements of one of the following motor types: a NEMA Design A, B, or C motor or an IEC Design N or H motor.

NEMA Design A motors, NEMA Design B motors, and IEC Design N motors manufactured (alone or as a component of another piece of equipment), on or after two years after the date of publication in the Federal Register, and distributed in commerce, as defined by 42 U.S.C. 6291 (16), that is NEMA Design A motors, NEMA Design B motors, and IEC Design N motors meeting the nine criteria above and with a power rating from 1 horsepower through 500 horsepower, but excluding fire pump electric motors, must have a nominal full-load efficiency of not less than the following:

Table 1: Full-Load Efficiencies for NEMA design A, NEMA design B and IEC design N motors (excluding fire pump electric motors) at 60 HZ
Motor Horsepower
2 poles 4 poles 6 poles 8 poles
Enclosed Open Enclosed Open Enclosed Open Enclosed Open
1 77.0 77.0 85.5 85.5 82.5 82.0 75.5 75.5
1.5 84.0 84.0 86.5 86.5 87.5 86.5 78.5 77.0
2 85.5 85.5 86.5 86.5 88.5 87.5 84.0 86.5
3 86.5 85.5 89.5 89.5 89.5 88.5 85.5 87.5
5 88.5 86.5 89.5 89.5 89.5 89.5 86.5 88.5
7.5 89.5 88.5 91.7 91.0 91.0 90.2 86.5 89.5
10 90.2 89.5 91.7 91.7 91.0 91.7 89.5 90.2
15 91.0 90.2 92.4 93.0 91.7 91.7 89.5 90.2
20 91.0 91.0 93.0 93.0 91.7 92.4 90.2 91.0
25 91.7 91.7 93.6 93.6 93.0 93.0 90.2 91.0
30 91.7 91.7 93.6 94.1 93.0 93.6 91.7 91.7
40 92.4 92.4 94.1 94.1 94.1 94.1 91.7 91.7
50 93.0 93.0 94.5 94.5 94.1 94.1 92.4 92.4
60 93.6 93.6 95.0 95.0 94.5 94.5 92.4 93.0
75 93.6 93.6 95.4 95.0 94.5 94.5 93.6 94.1
100 94.1 93.6 95.4 95.4 95.0 95.0 93.6 94.1
125 95.0 94.1 95.4 95.4 95.0 95.0 94.1 94.1
150 95.0 94.1 95.8 95.8 95.8 95.4 94.1 94.1
200 95.4 95.0 96.2 95.8 95.8 95.4 94.5 94.1
250 95.8 95.0 96.2 95.8 95.8 95.8 95.0 95.0
300 95.8 95.4 96.2 95.8 95.8 95.8 -- --
350 95.8 95.4 96.2 95.8 95.8 95.8 -- --
400 95.8 95.8 96.2 95.8 -- -- -- --
450 95.8 96.2 96.2 96.2 -- -- -- --
500 95.8 96.2 96.2 96.2 -- -- -- --

NEMA Design C motors and IEC Design H motors manufactured (alone or as a component of another piece of equipment), on or after two years after the date of publication in the Federal Register, and distributed in commerce, as defined by 42 U.S.C. 6291 (16), that is NEMA Design C motors and IEC Design H motors meeting the nine criteria above and with a power rating from 1 horsepower through 200 horsepower, must have a nominal full-load efficiency of not less than the following:

Table 2: Full-Load Efficiencies for NEMA design C and IEC design H motors at 60 HZ
Motor Horsepower
4 poles 6 poles 8 poles
Enclosed Open Enclosed Open Enclosed Open
1 85.5 85.5 82.5 82.5 75.5 75.5
1.5 86.5 86.5 87.5 86.5 78.5 77.0
2 86.5 86.5 88.5 87.5 84.0 86.5
3 89.5 89.5 89.5 88.5 85.5 87.5
5 89.5 89.5 89.5 89.5 86.5 88.5
7.5 91.7 91.0 91.0 90.2 86.5 89.5
10 91.7 91.7 91.0 91.7 89.5 90.2
15 92.4 93.0 91.7 91.7 89.5 90.2
20 93.0 93.0 91.7 92.4 90.2 91.0
25 93.6 93.6 93.0 93.0 90.2 91.0
30 93.6 94.1 93.0 93.6 91.7 91.7
40 94.1 94.1 94.1 94.1 91.7 91.7
50 94.5 94.5 94.1 94.1 92.4 92.4
60 95.0 95.0 94.5 94.5 92.4 93.0
75 95.4 95.0 94.5 94.5 93.6 94.1
100 95.4 95.4 95.0 95.0 93.6 94.1
125 95.4 95.4 95.0 95.0 94.1 94.1
150 95.8 95.8 95.8 95.4 94.1 94.1
200 96.2 95.8 95.8 95.4 94.5 94.1

Fire Pump electric motors manufactured (alone or as a component of another piece of equipment), on or after two years after the date of publication in the Federal Register, and distributed in commerce, as defined by 42 U.S.C. 6291 (16), that is fire pump electric motors meeting the nine criteria above and with a power rating from 1 horsepower through 500 horsepower, must have a nominal full-load efficiency of not less than the following:

Table 3: Full-Load Efficiencies for fire pump electric motors at 60 HZ
Motor Horsepower
2 poles 4 poles 6 poles 8 poles
Enclosed Open Enclosed Open Enclosed Open Enclosed Open
1 75.5 -- 82.5 82.5 80.0 80.0 74.0 74.0
1.5 82.5 82.5 84.0 84.0 85.5 84.0 77.0 75.5
2 84.0 84.0 84.0 84.0 86.5 85.5 82.5 85.5
3 85.5 84.0 87.5 86.5 87.5 86.5 84.0 86.5
5 87.5 85.5 87.5 87.5 87.5 87.5 85.5 87.5
7.5 88.5 87.5 89.5 88.5 89.5 88.5 85.5 88.5
10 89.5 88.5 89.5 89.5 89.5 90.2 88.5 89.5
15 90.2 89.5 91.0 91.0 90.2 90.2 88.5 89.5
20 90.2 90.2 91.0 91.0 90.2 91.0 89.5 90.2
25 91.0 91.0 92.4 91.7 91.7 91.7 89.5 90.2
30 91.0 91.0 92.4 92.4 91.7 92.4 91.0 91.0
40 91.7 91.7 93.0 93.0 93.0 93.0 91.0 91.0
50 92.4 92.4 93.0 93.0 93.0 93.0 91.7 91.7
60 93.0 93.0 93.6 93.6 93.6 93.6 91.7 92.4
75 93.0 93.0 94.1 94.1 93.6 93.6 93.0 93.6
100 93.6 93.0 94.5 94.1 94.1 94.1 93.0 93.6
125 94.5 93.6 94.5 94.5 94.1 94.1 93.6 93.6
150 94.5 93.6 95.0 95.0 95.0 94.5 93.6 93.6
200 95.0 94.5 95.0 95.0 95.0 94.5 94.1 93.6
250 95.4 94.5 95.0 95.4 95.0 95.4 94.5 94.5
300 95.4 95.0 95.4 95.4 95.0 95.4 -- --
350 95.4 95.0 95.4 95.4 95.0 95.4 -- --
400 95.4 95.4 95.4 95.4 -- -- -- --
450 95.4 95.8 95.4 95.8 -- -- -- --
500 95.4 95.8 95.8 95.8 -- -- -- --

The amended standards do not apply to the following electric motors:

(1) Air-over electric motors;

(3) Liquid-cooled electric motors;

(4) Submersible electric motors; and

(5) Inverter-only electric motors.

After a regulatory action has been completed, Executive Order 12866 requires agencies to identify the substantive changes between the draft submitted to Office of Information and Regulatory Affairs (OIRA) for review and the action subsequently announced, and to identify those changes made at the suggestion or recommendation of OIRA.

For more information, please see the rulemaking page.

Test Procedure for Electric Motors

Current Test Procedure

For purposes of Title 10 of the Code of Federal Regulations, Part 431, (10 CFR part 431) and the Energy Policy and Conservation Act, as amended, (EPCA) the test procedures for measuring the energy efficiency of an electric motor shall be the test procedures specified in 10 CFR 431.16 and appendix B to subpart B. The test procedures are also under subpart B of 10 CFR Part 431 in the Electronic Code of Federal Regulations.

Amended Test Procedures

After June 11, 2014, any representations made with respect to the energy use or efficiency of electric motors for which energy conservation standards are currently provided at 10 CFR 431.25 shall be in accordance with the results of testing pursuant to appendix B to subpart B of 10 CFR Part 431 ? Uniform Test Method for Measuring Nominal Full-load Efficiency of Electric Motors.

For further guidance or to submit questions related to the implementation of this test procedure, visit the Guidance and Frequently Asked Questions page.

Waivers, Exceptions, and Exemptions

Waivers

Test procedure waivers have not been issued for electric motors.

For information about obtaining test procedure waivers, see 10 CFR 431, subpart V.

Exceptions

The DOE Office of Hearings and Appeals has not authorized exception relief for electric motors.

For information about obtaining exception relief, see 10 CFR part 1003.

State Exemptions to Federal Pre-emption

DOE has not exempted any states from this energy conservation standard. States may petition DOE to exempt a state regulation from preemption by the Federal energy conservation standard. States may also petition DOE to withdraw such exemptions. For details, see 10 CFR 431, subpart W.

Statutory Authority

The current energy conservation standards for medium electric motors are mandated by Part A–1, the "Certain Industrial Equipment" of Title III of the Energy Policy and Conservation Act (EPCA), as amended. (42 U.S.C. 6311–6317). This equipment is treated as covered equipment under Part A-1. (42 U.S.C. § 6311(1)(A))

Historical Information

EPCA directs DOE to publish a final rule amending the standards in effect and to apply the rule to electric motors manufactured five years after the effective date EISA 2007. DOE is relying on the Congressionally established two-year spread between the effective date of the latest amendments to electric motor energy conservation standards and the date by which DOE must amend such standards to arrive at the two-year lead-time for manufacturers to comply with the rule after its date of issuance.

Previous Test Procedures

Final Rule: Test Procedures, Federal Register, 64 FR 54114 (Oct. 5, 1999)

Helpful Links and Contact Information

Helpful Links

Find tips and guidance for making your home, workplace, or vehicle more energy efficient visit EnergySavers.gov.

Contact information

For more information related to the regulation of this product, please email:


medium_electric_motors@ee.doe.gov