Three-phase monitoring relay, monitors the phase parameters phase failure, phase sequence and phase unbalance. Measuring Range (L-L) 300-500 VAC, operates with a rated control supply voltage of 300-500 VAC and have 2 CO (SPDT) output. An ON-delay is adjustable over a range of instantaneous to 30 s (0, 0.1-30 s). Double-chamber cage connection terminals