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Guidelines for Maintaining Motor Efficiency During Rebuilding

Publication date: 
November 2007
Type of media: 
Article

The challenge for every motor repair firm is twofold: to repair the equipment properly; and to demonstrate to their customers by means of adequate testing and documentation that rewound motors retain their operating efficiency. Following the guidelines in this document will help you accomplish both.

Numerous studies have been done to determine the effect rewinding has on motor efficiency. These studies identified several variables that can impact the efficiency of a rewound motor, including core burnout temperature, winding design, bearing type, air gap and winding resistance. The following guidelines were developed as a result of those studies, which found that the efficiency of both standard and energy efficient electric motors can be maintained during rebuilding and rewinding.

To ensure that motors retain their efficiencies when rewound, EASA also strongly recommends that electric motor repair centers comply with ANSI/EASA Standard AR100: Recommended Practice For The Repair Of Rotating Electrical Apparatus and strictly adhere to the “DOs” and “DON’Ts” presented in this article. These guidelines, which contain safe values (based on available data) and correct procedures, apply to both energy efficient and standard motors. Further study of the matter continues, and these guidelines will be revised if additional information warrants.

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Topic(s): 
AC motors
Laminations
Design/theory/application
Repair procedures and tips
Service center equipment
Motor testing