Littelfuse 250600, 250A Series, 3-Phase Voltage/Phase Monitor, Voltage Sensing AC 475 ~ 600VAC, DPDT (2 Form C)

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