The DPA55CM44 is a 3-phase monitoring relay designed to detect incorrect mains voltage, phase sequence errors, and phase loss in power supply systems. It monitors all three phases and operates only when all phases are present, the phase sequence is correct, and each phase-to-phase voltage is within the desired tolerance (±10% or ±15% selectable via DIP-switches). The relay features a wide power supply range of 208 to 480 VAC (±15%), a 5 A SPDT relay output (normally energized), and operates with a measuring range of 177 to 550 VAC with hysteresis less than 3V. The unit is housed in a compact 17.5 mm DIN-rail enclosure (17.5 × 81 × 67.2 mm) with LED indicators for power supply and relay status, making it suitable for mounting on DIN-rail according to DIN/EN/EC 60715. This relay is ideal for protecting equipment from voltage anomalies and phase sequence faults in industrial and commercial power distribution applications.