Phase Monitors

NAI's AC- and DC-powered Phase Monitors are used to protect three-phase loads from damage due to phase reversals or phase absence. Contacts may be used to disconnect the load or to operate alarm circuits or both. Upon application of power, the output relay energizes if all phases are connected and the phase sequence is ABC. If any phase becomes disconnected or if the phase rotation is abnormal, the relay immediately de-energizes. These monitors are specifically designed for rugged defense and industrial applications.

Click on the product links below for detailed product information.

ModelPowerInput ConfigurationVoltage (Operating)Frequency (Operating)Monitoring CharacteristicsContact FormPower DissipationInput Transients
PAA/PLAAC4-Wire Wye115 or 220 Vrms50, 60 or 400 HzPhaseDPDT or 3PDT4 WattsMIL-STD-704 
PAD/PLDDC4-Wire Wye28 VDCNot ApplicablePhaseDPDT or 3PDT3 WattsMIL-STD-704