250A | Littelfuse | Power Monitoring & Protection

The 250A three phase voltage monitor is an autoranging 3 phase voltage monitor designed to protect three phase motors regardless of size. It is used on a 190-480 volt AC, 50/60 Hz 3 phase motor to prevent damage caused by single phasing, low voltage, phase reversal, voltage unbalance, and high voltage. Added features include DPDT contacts and an adjustable restart time-delay setting. The unique microprocessor-based voltage and phase-sensing circuit constantly monitors the three phase voltages to detect harmful power line conditions. When a harmful condition is detected in a HVAC, industrial or BAS application, the three phase voltage monitor's output relays are deactivated after a fixed trip-delay time period. The output relay reactivates after power line conditions return to an acceptable level for an adjustable restart delay time. The trip and reset delays prevent nuisance tripping due to rapidly fluctuating power line conditions.

Littelfuse