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A thorough understanding of the revised standards is essential for all motor specifiers
"NEMA standard": What does that really mean? Now that the National Electrical Manufacturers Association has released ANSI/NEMA MG 1-20 11, latest edition of the motor and generator standards, a close look at this document is in order. What's in it, and what's not?
As for the nature of MG 1 : A "Notice and Disclaimer" preamble says this:
"While NEMA administers the process and establishes rules to promote fairness in the development of consensus, it does not write the document and it does not independently test, evaluate, or verify the accuracy or completeness of any information or the soundness of any judgments contained in its standards, ..."
Despite the disclaimer, NEMA's Motor & Generator Section Web site states that "key technical activities" of that Section "include development and updating of motor and generator standards, including MG 1 " Without the concerted effort of the corporate members of that Section, MG 1 would not exist.
Motor users aren't always aware of one important respect in which MG 1 differs from standards of the IEEE, or the NFPA. Other organizations generally require "balanced" makeup of the standards-writing group. Viewpoints of users, consultants, and other concerned parties need to be represented. NEMA MG 1 , in contrast, is written by motor manufacturers only. What installers or operators should find acceptable can be taken into account only insofar as feedback reaches a manufacturer. Of course, the marketplace determines how well expectations are met.
In March 1993, the Motor & Generator Section did sponsor a user conference bringing together both sides of the market. The conference's purpose was "to promote better communication between manufacturers and user organizations, and to give users a direct voice in the NEMA standards-making process" [author's emphasis]. A major issue aired at that meeting was the pump industry's need for additional standard requirements dealing with installation and alignment of pump drives. Some MG 1 changes resulted. A second such meeting was held the following year. But there were no more, although other meetings with wider participation (including government agencies) were held regarding efficiency issues.
The composition of the association
What is NEMA? It began with formation of the Electrical Manufacturers Alliance...