RM22TR series three-phase voltage control relay monitors phase sequence, phase loss and undervoltage and overvoltage. An adjustable time delay on threshold crossing provides immunity to transients and helps prevent spurious triggering of the output relay. If a voltage fault is detected, the relay opens at the end of the time delay set as On-delay or Off-delay by the user. On energization of the device with a detected measured fault, the relay stays open.