The 250A series is a three-phase, auto-ranging, dual-range voltage monitor that protects 190–480 V ac, 50*/60 Hz motors regardless of their size. This monitor offers protection from low- and high-voltage, voltage unbalance, single-phase, and phase reversal. The 250A provides a user-selectable nominal voltage setpoint and will automatically select between the 200 V and 400 V range. This monitor also features adjustable or manual restart delay. This unique microcontroller-based voltage and phase-sensing device constantly monitors the three-phase voltages to detect harmful power line conditions. When a harmful condition is detected, the output relay is deactivated after a specified trip delay. The output relay reactivates after power line conditions return to acceptable levels. The 250A monitor includes advanced, single LED diagnostics. Five different light patterns distinguish between faults and normal conditions. LED indications include normal operation, power-up restart delay, reverse-phase trip, unbalance/single-phase trip, and high/ low voltage trip. Applications• Fan motors• Air conditioners• Compressors• Heat, well, and sump pumps• Small conveyer motors *Note: 50 Hz will increase all delay timers by 20% Specifications Frequency 50*/60 Hz Low Voltage Functional Characteristics Voltage Unbalance (NEMA) Trip 6%Reset 4.5% Trip Delay Time Low Voltage, High Voltage: 4 secondsUnbalance, Phasing Faults: 2 seconds Restart Delay Time After a Fault or Complete Power Loss Manual, 2–300 seconds adjustable Output Characteristics Output Contact Rating (DPDT - 2 Form C) Pilot Duty: 480 VA @ 240 V acGeneral Purpose: 10 A @ 240 V ac Temperature Range -40° to 70 °C (-40° to 158 °F) Trip & Reset Accurac ±1% Maximum Input Power 5 W Relative Humidity Up to 95% non-condensing per IEC 68-2-3 Terminal Torque 7 in.-lbs. Wire Size 12–18 AWG Transient Protection (Internal) IEC 61000-4-5; 1995 ±6 kV Dimensions H 74.4 mm (2.93”)W 133.9 mm (5.27”)D 74.9 mm (2.95”) Weight 1.02 lb. (16.32 oz., 462.66 g) Mounting Method #8 screws Certification & Compliance UL UL 508 (File #E68520)CSA CSA 22.2 No. 14 (File#46510)