CMI AC Over Current Monitor

The CMI Series AC OVER CURRENT Monitor Relay operates in the FAILSAFEMODEL as the relay is energized pick-up when the monitoredAC current is normal. The relay de-energizes Drop-out when themonitored current rises above the preset trip point or the control voltageis removed. When current is initially applied, a time delay begins.This inhibits the over current sensors while high inrush currents arepresent. The delay is field adjustable and is set so the delay periodis slightly longer than the inrush time of the motor. If the monitoredcurrent is above the preset trip point when the delay elapses, the relayde-energizes. If the current drops to the normal run currentof the motor prior to the completion of the delay period, the relayremains energized until the current rises above the trip point, whichindicates an abnormal condition. At that time the relay deenergizes andremains locked-out until the reset button is pressed or the control voltageis interrupted, and re-applied. A typical application is forconveyor jam up detection.An External CT may be used to extend the range of the Current Monitor.