Addressing nuisance tripping of instantaneous trip breakers in high efficiency motor applications

Abstract

Reviewing the motor starting current phenomena from high-efficiency motors and the National Electric Code requirements for instantaneous circuit breakers, the author has determined that there are conflicts. To address this situation, the author is proposing changes to the National Electric Code and the addition of new test requirements for the qualification or listing of the coordinated protective combination starters. With this in place, new guidelines for settling the adjustment of instantaneous circuit breakers in high-efficiency motor applications are established. It is noted that this new method is easier for the user to apply, permits higher trip settings to address nuisance tripping on high-efficiency motor applications, and provides improved coordination protection.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>