• Monitors for Phase Loss or Reversal, Low Voltage or Voltage Unbalance
• Automatic Reset
• Heavy Duty DPDT Output Contacts
• UL Listed to U.S. and Canadian Safety Standards

The Models 2500D and 2501D 3-Phase Monitors are designed to continuously monitor the voltages of a 3-phase power distribution system for abnormal conditions. The monitors feature solid-state voltage and phase angle sensing circuits which drive a DPDT electromechanical output relay. A neutral connection is not required with either the Model 2500D or 2501D. This allows each model to be connected to any three phase WYE or DELTA configured power distribution system.

When the correct voltage and phase sequence is applied to a specified Model 2500D, the output relay will not energize. An under voltage, phase reversal, phase unbalance or phase loss condition will cause the output relay to energize, even if regenerated voltage is present. Complete power loss will not cause Model 2500D to trip.

When the correct voltage and phase sequence is applied to a specified Model 2501D, the output relay will energize. An under voltage, phase reversal, phase unbalance, or phase loss condition will cause the output relay to de-energize.

Each option on the Model 2500D or 2501D is adjustable throughout its operating range. The adjustment pots and L E D indicators for VOLTAGE ADJUST, UNBALANCE ADJUST and TIME DELAY are mounted on the front of the unit, for easy access.

Seven versions of both the Model 2500D and the Model 2501D cover voltage ranges from 120 to 600 VAC. All models are UL Listed to U.S. and Canadian safety standards.