by John Malinowski, Baldor Electric Company

Green Motors Save Greenbacks

Prepare for the new motor manufacturing changes with the Energy Independence and Security Act of 2007.

The U.S. has not enacted a wide-reaching, industrial energy efficiency bill since 1992 when the Energy Efficiency Policy Act was passed. This mandated that most general-purpose AC induction motors of 1 through 200 horsepower were required to be built to energy efficient levels per NEMA MG 1, Table 12-11 as of October 1997.

EISA 2007

The Energy Independence and Security Act of 2007 (EISA) was passed by Congress and signed into law on December 19, 2007. EISA builds upon the previous EPAct (Energy Policy Act of 1992) updating mandated efficiency standards for general purpose, three-phase AC industrial motors from 1 to 500 horsepower that are manufactured for sale in the U.S.

The U.S. Department of Energy (DOE) is responsible for establishing the rules to implement and enforce EPAct. EISA applies to motors manufactured after December 19, 2010.

Simply stated, if a 1 to 200  horsepower motor were required to comply with EPAct 1992, its efficiency must be raised to comply with NEMA MG 1, Table 12-12, for premium efficient motors. Pump manufacturers will also be affected because close-coupled pump motors are now required to comply with NEMA MG 1, Table 12-11, for energy efficient motors. Both changes will result in motors using more active material (such as copper, laminations, aluminum) and most likely higher-grade electrical steel for lower energy losses.

Motors Affected by EISA

The efficiency standards under EISA for each general-purpose rating (Subtype I) from 1 to 200 horsepower that was previously covered by EPAct specifies a nominal, full-load efficiency level based on NEMA Premium® efficiency as shown in NEMA MG 1, Table 12-12. All such motors currently under EPAct, manufactured after December 19, 2010, must meet or exceed this efficiency level.

General Purpose Electric Motors (Subtype II) not previously covered by EPAct will be required to comply with energy efficiencies as defined by NEMA MG 1, Table 12-11. The term general purpose electric motor (Subtype II) means motors incorporating the design elements of a general purpose electric motor (subtype I) that are configured as one of the following:

  • U-frame motor
  • Design C motor
  • Close-coupled pump motor
  • C-face or D-flange footless motor
  • Vertical, solid-shaft normal thrust motor (as tested in a horizontal configuration)
  • An eight-pole motor (900 rpm)
  • A poly-phase motor with voltage of not more than 600 volts (other than 230 or 460 volts)
  • 201 to 500 horsepower motors not previously covered by EPAct will be required to comply with energy efficiencies as defined by NEMA MG 1, Table 12-11

Only 1 to 500 horsepower motors with three-digit frame NEMA numbers (143T-up) are included in the EISA requirements. This also includes equivalent IEC frame designations.

In most instances, the EISA-mandated efficiency levels of for Subtype I motors (1 to 200 horsepower) fall at the existing NEMA Premium® efficient motors for general-purpose motors.

The Subtype II motors (from 1 to 200 horsepower) and general purpose motors (from 201 to 500 horsepower) may require manufacturers to raise the efficiency of some designs to comply with MG 1, Table 12-11. However, many designs may already comply. NEMA Premium® efficient motors will meet or exceed the EISA requirements for either of these motor types.

EISA requires that any custom motors included in OEM equipment that fall within the guidelines of the act comply with the efficiency levels for that motor type. Each OEM should prepare for the changes well before December 2010 and develop designs immediately, particularly when UL or CSA approvals are required.

EISA makes no distinction for duty cycle rating. Again, the terms electric motors and general purpose must be used as defined by the EPAct to determine if a particular design is affected by the requirements. The DOE considers motors built to IEC metric frame dimensions equivalent to NEMA T-frame dimension to fall under EISA.

EISA also makes no distinction between stock or custom motors. The determining factor under EISA is whether a particular motor meets the law's definition of electric motor. Motors manufactured outside the U.S. and imported for use within the U.S. are also affected by EISA. This includes electric motors that are components of another piece of equipment.

Motors Not Affected by EISA

Fractional horsepower and 48- or 56-frame motors are not included in EISA. Along with these, several other motor configurations are not covered by EISA, such as:

  • Single phase motors
  • DC motors
  • Design D with high slip
  • Adjustable speed with optimized windings
  • Customized OEM mounting
  • Intermittent duty
  • Integral with gearing or brake where motor cannot be used separately
  • Submersible motors

While not every three-phase electric motor from 1 to 500 horsepower falls under EISA, almost all motors, except some special OEM designs with proprietary mounting configurations, do. The following motor configurations are exempt from EISA compliance:

  • Integral gearmotors
  • Integral brake motors
  • Inverter duty motors with windings optimized for ASD use that cannot be line-started
  • Design D high-slip motors

EISA does not apply to motors exported outside the U.S., including motors mounted on equipment. The DOE will require these motors or their boxes to be specifically marked “Intended for Export.” Countries outside the U.S. are enacting their own Minimum Efficiency Performance