ANSI/IEEE 620-1981

This guide defines thermal limit curves, recommends a standard procedure for construction of the curves, and provides the definitions and information necessary t o properly use these curves. 2.2 The guide also describes thermal limit curves for large squirrel-cage motors defined as those motor ratings built in frames larger than the frame normally used for 500hp , 1800r/min motors.

The purpose of this guide is to assist in a uniform understanding of the construction, interpretation, and use of motor thermal limit curves.

New IEEE Standard - Superseded.