Series: TVM

The TVM series is a three-phase voltage monitor that provides protection for motors and other sensitive loads. It continuously measures the voltage of each of the three phases using a microcomputer circuit design that senses under and overvoltage, voltage unbalance, phase loss, and phase reversal. Protection is provided even when regenerated voltages are present. This monitor includes a trip delay to prevent nuisance tripping and a restart delay to prevent short cycling after a momentary power outage.

Operation
Upon application of line voltage, the restart delay begins, and the output relay is de-energized. Under normal conditions, the output energizes after restart delay. Undervoltage, overvoltage, and voltage unbalance must be sensed for a continuous trip delay period before the output is de-energized. The output will not de-energize if a fault is corrected during the trip delay. The restart delay begins as soon as the output relay de-energizes. If the restart delay is completed when the fault is corrected, the output relay will energize immediately. The output relay will not energize if a fault or phase reversal is sensed as three-phase input voltage is applied. Reset is automatic upon correction of a fault.

LED Operation
The LED flashes green during the restart delay, then glows green when the output energizes. It flashes red during the trip delay, then glows red when the output de-energizes. It flashes red/green if phase reversal is sensed.