Activities of the NEMA Equipment Subcommittee and Joint Sections Committee on magnet wire for inverter driven motors

The NEMA equipment subcommittee is in the process of investigating several different magnet wire testing procedures. These studies have led to several revisions in NEMA MW 1000 Part 3 as seen in the 1997 edition and will result in other enhancements in the near future. This paper highlights the status of three of the magnet wire testing procedures being addressed by this committee. They are: (1) high voltage DC continuity testing using a carbonized foam; (2) recommending test loads for flow temperatures for various magnet wire AWG sizes; and (3) the dissipation factor cure test for polyimide wire. A NEMA joint sections' committee has been formed between the Magnet Wire section; 7-MW, the Motor Generator Section; 1-MG, with representation from the Insulating Resins section; 6-RE, to develop testing procedures and performance specifications for magnet wire and insulation systems which may be used in inverter driven motors. This paper describes the formation, goals and status of this Committee.