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Study shows electric motors can be rewound without reducing efficiency

St. Louis, MO -- Oct. 28, 2002 -- The results of a new study on the impact of rewinding on the energy efficiency of...


St. Louis, MO — Oct. 28, 2002 — The results of a new study on the impact of rewinding on the energy efficiency of electric motors have been released by the Electrical Apparatus Service Association (EASA). The study concludes that using best repair/rewind practices maintains a motor’s energy efficiency.

Typically, over 97 per cent of the lifetime cost of an electric motor is the electricity it uses to operate. Even small changes in a motor’s efficiency can have a large effect on operating costs.

There is a common misconception that rewinding a motor will degrade its efficiency, a misconception that may influence the user’s decision in deciding whether to repair or replace a failed motor. Based on the results of the study, it is clear that electric motors can be rewound/repaired multiple times with no change to operating costs.

This comprehensive study was launched in 2000 under the leadership of EASA and the Association of Electrical and Mechanical Trades of the United Kingdom. Other project sponsors included the U.S. Department of Energy and the U.K.’s Energy Efficient Best Practice Program.

Ten of the world’s largest electric motor manufacturers provided motors, technical data and assistance. The motors examined were 50 hp to 300 hp electric motors and included low and medium voltages, IEC and NEMA designs, totally enclosed and open drip-proof, and 1,800 rpm and 3,600 rpm ratings.

A white paper, “The Results are In: Motor Repair’s Impact on Efficiency,” can be viewed at www.easa.com.