The PLR Series provides a cost effective means of preventing 3-phase motor startup during adverse voltage conditions. Proper A-B-C sequence must occur in order for the PLR’s output contacts to energize. In addition, the relay will not energize when an undervoltage or phase loss condition is present. The PLR Series protects a motor against undervoltage operation. The adjustment knob sets the undervoltage trip point. OperationThe output relay is energized and the LED glows when all voltages are acceptable and the phase sequence is correct. Undervoltage must be sensed for a continuous dropout delay period before the relay de-energizes. Reset is automatic upon correction of the fault condition. The output relay will not energize if a fault condition is sensed as power is applied.Field Adjustment: Turn the adjustment knob fully counterclockwise and apply three-phase power. The LED should be ON. Increase adjustment until the LED goes OFF. Decrease adjustment until LED glows again. If nuisance tripping occurs, decrease the adjustment slightly. NOTE: When properly adjusted and operating in an average system, a voltage unbalance of 10% or more is required for phase loss detection. When a phase is lost while the motor is running, a voltage will be induced into the open phase nearly equal in magnitude to the normal phase-tophase voltage. This condition is known as regeneration. When regenerated voltages are present, the voltage unbalance during single phasing may not exceed 10% for some motors. The PLR Series may not provide protection under this condition. For systems that require superior phase loss protection, select the PLMU Series. *CAUTION: Select an octal socket rated for 600VAC operation. Line Voltage Type 3-phase delta or wye with no connection to neutral Line Voltage 200 to 480VAC ±15%, 50/60 Hz ±2 Hz Nominal Voltage120VAC240VAC380VAC480VAC UndervoltageDropout Adj. Range Line Voltage Max.85 to 130VAC 143VAC170 to 240VAC 270VAC310 to 410VAC 480VAC350 to 480VAC 530VAC AC Line Frequency 50/60Hz Phase Sequence ABC Response Times Pull-in ≤ 400ms Drop-out ≤ 100ms Hysterisis Pull-in/Drop-out ≅ 2% Output Type Electromechanical relay, energized when all voltages are acceptable Form SPDT Rating 5A resistive @ 240VAC, 1/4 Hp @ 120VAC Maximum Voltage 250VAC Protection Phase Reversal/Failure ASME A17.1 Rule 210.6 Motors and Generators NEMA MG1 14:30, 14:35 Surge IEEE C62.41-1991 Level B Isolation Voltage 120 & 240VAC ≥ 1500V RMS input to output 380 & 480VAC ≥ 2500V RMS input to output Mechanical Dimensions H 81.3 mm (3.2”)W 60.7 mm (2.39”)D 45.2 mm (1.78”) Mounting* Plug-in socket Termination Octal 8-pin, plug-in Environmental Operating/Storage Temperature 0° to 55°C / -40° to 85°C Weight ≅ 6 oz (170 g)
