Protection Relays Voltage Monitoring Relays 250A SERIES 3-Phase Voltage/Phase Monitor Description The 250A is a 3-phase, auto-ranging, dual-range voltage monitor that protects 190480 V ac, 50/60 Hz motors regardless of size from low and high voltage, unbalance/single-phase, and reverse- phase. The product provides a user selectable nominal voltage setpoint and the voltage monitor automatically selects between the 200 V and 400 V range. The 250 A also features adjustable or manual restart delay. This unique microcontroller-based voltage and phase-sensing device constantly monitors the 3-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 Model 250 A includes advanced single LED diagnostics. Five different light patterns distinguish between faults and normal conditions. Wiring Diagram Features & Benefits FEATURES BENEFITS Proprietary Constant monitoring of single-phase, low microcontroller voltage, voltage unbalance, phase reversal, based circuitry harmful power line conditions. Auto-sensing wide Automatically senses system voltage between voltage range 190480 V ac. Saves setup time. MODEL 250 Quick visual indicator for cause of trip. LED Advanced LED indications include: normal operation, power-up diagnostics restart delay, reverse-phase trip, unbalance/ single-phase trip, high or low voltage trip Prevent nuisance tripping due to rapidly Adjustable trip delay fluctuating power line conditions. Allows for versitility to meet wide application DPDT relay output needs Allows for inspection of equipment before Manual Reset system is re-energized Ordering Information % OF SETPOINT LINE MODEL LOW LOW HIGH HIGH DESCRIPTION VOLTAGE VOLTAGE VOLTAGE VOLTAGE VOLTAGE TRIP RESET TRIP RESET 250A 190480 V ac 90 % 93 % 110 % 107 % Provides high and low voltage protection at fixed percentage of nominal voltage. 250600 475600 V ac 90 % 93 % 110 % 107 % Provides high and low voltage protection at fixed percentage of nominal voltage. Designed for use with Fire Control Panels. Has 2 Form C contacts that operate independently. Left Form C energizes when voltage conditions are good and 250A-MET 190480 V ac 85 % 88 % N/A N/A de-energize when a fault condition is detected. Right Form C only energizes during a reverse-phase condition. No high voltage protection. Designed for use with Fire Control Panels. Has 2 Form C contacts that operate independently. Left Form C energizes when voltage conditions are good and 250-100-MET 95120 V ac 85 % 88 % N/A N/A de-energize when a fault condition is detected. Right Form C only energizes during a reverse-phase condition. No high voltage protection. 2020 Littelfuse, Inc. Rev: 1-A-062716Rev: 2-A-061220 wwwwww.littelfuse.com/250a.littelfuse.com/Protection Relays Voltage Monitoring Relays 250A SERIES 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 seconds Unbalance, Phasing Faults 2 seconds Restart Delay Time After a Fault or Complete Power Loss Manual, 2300 seconds adj. Output Characteristics Output Contact Rating (DPDT - 2 Form C) Pilot Duty 480 VA 240 V ac General Purpose 10 A 240 V ac Temperature Range -40 to 70C (-40 to 158F) Trip & Reset Accuracy 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 1218 AWG Transient Protection (Internal) IEC 61000-4-5 1995 6 kV Approvals UL UL 508 (File E68520) CSA CSA 22.2 No. 14 (File 46510) 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 *Note: 50 Hz will increase all delay timers by 20 %. 2020 Littelfuse, Inc. Rev: 1-A-062716Rev: 2-A-061220 wwwwww.littelfuse.com/.littelfuse.com/250a