Electric Motors

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THE PRODUCT:

Electric motors convert electrical energy into mechanical energy. Current energy conservation standards for electric motors cover subtype I and subtype II general purpose electric motors (1-200 horsepower (hp)), fire pump motors (1-500 hp), and National Electrical Manufacturers Association (NEMA) Design B general purpose electric motors (200-500 hp). Typical applications for electric motors include pumps, fans, blowers, and compressors.

THE STANDARD:

The energy efficiency of electric motors, expressed as a percentage, is the ratio of useful power output to total power input. The minimum efficiency standards depend on the motor horsepower, number of poles (number of sets of electromagnetic windings), and enclosure type (open or closed). EPACT 1992 established the first federal energy conservation standards for certain commercial and industrial electric motors. EISA 2007 amended the electric motor standards and expanded the scope of covered motors. The EISA standards, which became effective in December 2010, require that general purpose electric motors (subtype I) meet “NEMA Premium” levels and that general purpose electric motors (subtype II), fire pump motors, and NEMA Design B general purpose electric motors meet “NEMA Energy Efficient” levels. “NEMA Premium” motors are more efficient than “NEMA Energy Efficient” motors.

The 2012 ASAP/ACEEE report, The Efficiency Boom, analyzed a standard level which includes an increase to the NEMA Premium levels for most of the few categories of currently covered motors subject to lower standards. However, most benefits derive from an expanded scope of coverage to include products not previously subject to standards. The average estimated per-unit savings are 2%, with an incremental cost which varies based on motor size. Typical payback periods are about 4 years. DOE is required to publish a final rule amending the current standards by December 2012.

The statutory deadline for the final rule was December 19, 2012. DOE missed the deadline.

KEY FACTS:

Technology options for meeting the standard include improved bearings, a more efficient cooling system, improved grades of electrical steel, and using thinner steel laminations. Electric motors account for approximately 60% of electricity consumption in industrial applications. About 1.6 million electric motors are shipped annually.