250A SYMCOM 3-Phase Voltage Monitor
- Product Type: Voltage Monitor
- Manufacturers: Littelfuse
- Product Family: SYMCOM
- Frequency: 50/60Hz
- Input Voltage: 190-480VAC
- Max Operating Temperature: 158 F
- Min Operating Temperature: -40 F
- Mounting Method: #8 Screws
- Output Form: DPDT - 2
- Output Load Rating: 10A @ 240VAC
- Output Load Rating Pilot Duty: 480VA @ 240VAC
- Overvoltage Reset Voltage: 107%
- Overvoltage Trip Voltage: 110%
- Restart Delay Range: Manual 2-300s adj
- Trip Delay Range: Under/Over Voltage 4s; Unbalance/phasing faults 2s
- Trip Point Accuracy: +/-1%
- Undervoltage Reset Voltage: 93%
- Undervoltage Trip Voltage: 90%
- Voltage Unbalance Reset: 4.5%
- Voltage Unbalance Trip Point: 6%
The 250A is a 3-phase, auto-ranging, dual-range voltage monitor that protects 190-480VAC, 50*/60Hz 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 200V and 400V range. The 250A 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 Littelfuse's output relay is deactivated after a specified trip delay.
The output relay reactivates after power line conditions return to acceptable levels. The Model 250A includes advanced single LED diagnostics. Five different light patterns distinguish between faults and normal conditions.