NEMA design E motors and controls-what's it all about?

Quite a bit of confusion exists in industry on the new NEMA design "E" motors and the associated equipment used to control them. While considerable information has been published on the motors themselves, articles typically do not cover both the motor and related control aspects. This paper first discusses the motor design background and related issues and then moves to the effects on motor controls. Issues covered include: characteristic's of NEMA Design E motors; the impact of the 1997 Federal Mandate on energy efficient motors; UL's position on test requirements for motor controllers used with NEMA Design E motors; the potential for nuisance tripping of overload relays and instantaneous circuit breakers; and the new Design E rating rules in Article 430 of the 1996 National Electrical Code.