The PMPU is a 3-phase Multifunction Monitoring Relay with SPDT, SPST-NC contact and quick connect terminals. This PMP-series monitor relays continuously monitor all voltages of a three-phase system. They are used to protect motors and equipment from expensive damage due to phase loss, phase reversal, phase unbalance, under-voltage and overvoltage faults as well as rapid cycling. These products detect single phasing and unbalanced voltages regardless of regenerative voltages. The PMP-series incorporate a microprocessor-based design capable of advanced signal processing including true RMS voltage measurement. Innovative analog to-digital sensing circuitry allows for true full-wave monitoring of all three phases, delivering the highest level of protection possible. True RMS voltage measurement ensures accurate sensing in most generator and other applications with non-sinusoidal wave forms, eliminating nuisance tripping.