3-phase power relay


3PHMR1 is a monitoring relay suitable 3-phase without neutral mains. It protects loads from wrong phase sequence, phase loss, Phase Unbalance and under voltage, over voltage.

User can adjust the ranges as per the based on the set values in potentiometer and as soon as wired it is ready for operation. Power supply is provided by the measured mains, and it is switch mode, making it wide range and immune to mains disturbances, transients and harmonics problems. Additional protection, against dust and humidity, is provided by the PCB conformal coating. The output signal is a 5A changeover electromechanical relay.

4 front LED's provide visual indication of output state and fault discrimination. Thanks to the low profile DIN construction it is possible to install it either in industrial cabinets as well as NORM distribution panels.


  • Measuring Voltage Range : 180V-440V AC MAX.
  • Very wide input voltage range: from 183 V to 528V.
  • LED indication: Its use to indicate Phase sequence/Phase loss/Unbalance and under voltage and over voltage conditions.
  • Outputs LED indication: A yellow LED provides visual indication of the output status.
  • High Compactness: The 3PHMR1 is a 3-Phase monitoring relay with 17.5mm width.


3PHMR1 is suitable for all applications where it is necessary to monitor phase presence, correct phase sequence and Under voltage, Over Voltage of three phase load mains: lifts, escalators, HVAC, material handling, conveyors, pumps and compressors.

Protection devices

Caliber can support with following protection devices:

  • Overvoltage/overcurrent protection.
  • Surge protection.
  • In-rush protection.
  • Arcing detection and protection.
  • Earth fault detection and protection.
    • Main function:

      • 3Ph monitoring.
      • From 208V to 480V rated input.
      • Phase sequence, Phase loss, Phase unbalance, Under voltage, Over voltage.
      • 5A SPDT relay output.
      • DIN Enclosure.