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ANSI/EASA AR100: What's in it for the end user?

Electrical Business
Publication date: 
March 2014
Tom Bishop, P.E., EASA Senior Technical Support Specialist

ANSI/EASA AR100 “Recommended Practice for the Repair of Rotating Electrical Apparatus” (2010) provides good practices for mechanical repair, rewinding and testing that help apparatus rebuilders maintain or enhance the energy efficiency and reliability of both AC and DC motors and generators. The focus of this article is strictly on the electrical aspects of AC machine repair prescribed in this standard.

Many of the practices in AR100 help maintain motor efficiency. These practices were identified as part of a comprehensive ‘rewind study’ that was published in 2003 by EASA (Electrical Apparatus Service Association) and the Association of Electrical and Mechanical Trades (AEMT), a service center association in United Kingdom.

One value of AR100 for end users is that it concisely describes good repair practices in just 22 pages. Another is that, by requiring service centers to comply with the recommended practices in AR100, end users can be assured that repairs will be made in accordance with a recognized standard. The result should be a quality repair without shortcuts.

Other topics covered include:

  • General guidelines
  • Rewinding
    - Winding data
    - Stator core testing
    - Winding removal
    - The insulation system
    - Rewind procedure and slot fill
    ​- Winding impregnation
  • Testing and inspection
    - Inspection
    - Insulation resistance test
    - Surge comparison tests
    - High-potential tests
    - No-load testing
  • Instrument calibration