Description

This monitoring relay is engineered to deliver comprehensive system protection across three distinct fault profiles. First, it actively enforces structural line integrity via Phase Failure Monitoring, instantly tripping the contact loop if any individual line drops below its operational threshold to prevent single-phasing asset damage. Second, its Phase Sequence Monitoring logic verifies incoming rotational topology upon initialisation to guarantee that motors, pumps, and compressors cannot run in reverse. Finally, it provides high-sensitivity Asymmetry Detection, continuously calculating line-to-line voltage deviations to isolate the downstream load before unbalance-induced thermal breakdown occurs in the connected machinery.

Phase failure monitoring

When one of the three phases fails, the output relays switch into off-position (yellow LED not illuminated).

Phase sequence monitoring

When all the phases are connected in the correct sequence and the measured asymmetry is less than the fixed value, the output relays switch into on-position (yellow LED illuminated). When the phase sequence changes, the output relays switch into off-position (yellow LED not illuminated).

Detection of reverse voltage (by means of evaluation of asymmetry)

The output relays switch into off-position (yellow LED not illuminated) when the asymmetry between the phase voltages exceeds the fixed value of the asymmetry. An asymmetry caused by the reverse voltage of a consumer (e.g. a motor which continues to run on two phases only) does not effect the disconnection.

Circuit Diagram