APPARATUS FOR INDICATING WHEN CURRENT EXCEEDS A PREDETERMINED LEVEL AND WHEN SAID LEVEL IS EXCEEDED FOR A PREDETERMINED PERIOD OF TIME

摘要

Transformer fault current monitor which provides recorded indications of the number of times any fault currents have occurred and also of the number of times fault currents which have a duration of more than a predetermined length of time have occurred. Current transformers coupled to the monitored current provide output voltages which are rectified and peak detected. The peak detected voltages are applied to first and second counting means. The first counting means is activated when the monitored current exceeds a predetermined level. The second counting means is activated when the monitored current exceeds a predetermined level for a predetermined length of time.