Phase Failure Relay

Different phase failure relays feature different functions to protect magnetically controlled 3-phase equipment against damage caused by abnormal phase conditions such as open phasing or single phasing. It is worth nothing phase failure relays only detect problems and temporarily cut off the circuit for protection. They do not solve whatever caused the problem to begin with.

Protection mode: The main circuit is cut off automatically for a specified amount of time, then resets when the failure or problem is solved.

Typical problems are as follows.

• Phase failure/Phase loss: One of the three phases is powered off.
• Phase reversal: Generally, the three phases run clockwise by 120 degrees with each other. However, the rotational direction may be reversed due to maintenance on motor-driven machinery or modifications to the power distribution system.
• Three-phase unbalance: It means that the amplitude of three-phase current (or voltage) is inconsistent in the power system, and the amplitude difference exceeds the specified range.
• Overvoltage: The voltage fluctuation exceeds the set value.
• Undervoltage: The voltage fluctuation is lower than the set value.

We offer phase failure relays in different styles, shapes, and voltage ranges.