Portable Calibrator for DC Circuit Breakers. Phase IV Report. Circuit Breaker Development and Application.

摘要

A portable calibrator to check the trip setting of dc circuit breakers within an accuracy of plus or minus 5pct was developed for the Bureau of Mines. The calibrator operates from a 300-volt dc trolley wire to provide controlled current pulses of 120msec duration and continuously adjustable from 1,400to 3,600 A. These current pulses enable a breaker dc trip current to be determined and subject the contacts to full current rating. The equipment is simple to use and weighs 86lb. Connections are made with protected,clamp-on leads that are separately connected and weigh about 22lb. An accurate calibration procedure takes less than 5min to complete.