The CMG Series is a self powered Current Monitor/Relay that is used to detect the presence of AC current. When the monitored current exceeds the trip point for longer than 400 mSec., the internal relay energizes (Pick-up). When the monitored current drops below the trip point for longer than 50 mSec., the internal relay de-energizes (Drop-out).
No physical connection is required as the line to be monitored is magnetically coupled by passing the conductor through the protruding Current Transformer of the monitor. No external supply is needed to power the monitor. The current trip point specified is with one turn through the transformer. Each time the number of turns through the transformer doubles, the trip point effectively halves.