The PMRU-2C series true RMS phase monitor relays protect 3-phase equipment from damage that can occur when there is a phase loss, phase reversal, phase unbalance, undervoltage or overvoltage condition. These relays are designed to provide protection for most generator systems and applications that use non-sinusoidal waveforms. With non-sinusoidal waveforms, the true RMS voltage measurement ensures accurate sensing, eliminating nuisance tripping.
Also added are voltage monitor relays for AC single-phase (50 to 60 Hz) or DC circuits to protect equipment from voltage faults. Over/under voltage relays, with fixed or adjustable time-delay drop-out, offer protection from over-or under-voltage conditions. Voltage band relays protect equipment required to operate within an upper and lower voltage limit. The relay is energized if the monitored voltage remains within the adjustable range.