The Model 2500D 3-Phase Monitors are designed to continuously monitor the voltages of a 3-phase power distribution system for abnormal conditions. The monitors feature solid-state voltage and phase angle sensing circuits which drive a DPDT electromechanical
output relay. Connect to any 3-phase WYE or DELTA with no neutral connection required.

When the correct voltage and phase sequence is applied, the output relay will not energize. An under voltage, phase reversal, phase unbalance or phase loss condition will cause the output relay to energize, even if regenerated voltage is present. Complete power loss will not cause the Model 2500D to trip.