Three-phase phase monitoring relay | 3x380V | phase asymmetry 30% | DIN

The device is designed for 3x380V AC + Neutral electrical systems and has fixed 30% phase asymmetry protection. When all phase voltage values are normal, the relay is activated. If the voltage of one phase increases or decreases enough to exceed the permitted asymmetry threshold, the relay is deactivated and the control circuit can disconnect the protected equipment.

The device has a factory-set 30% phase asymmetry threshold. If the voltage deviation of one or more phases exceeds this limit, the relay output is deactivated. This protection helps reduce the risk of overheating, uneven operation, and other faults in three-phase motors that may be caused by significant phase voltage imbalance.

This relay version is designed for a 3x380V AC network with neutral connection. The neutral conductor is part of the device wiring diagram. This version does not have a phase sequence monitoring function – its primary purpose is phase condition monitoring and fixed 30% voltage asymmetry protection.

• Designed for three-phase 3x380V AC systems with neutral connection.
• Fixed 30% phase asymmetry protection.
• Helps protect three-phase motors against operation under significant phase voltage imbalance.
• Automatic network condition monitoring without additional user adjustment.
• Clear ON and OUT LED indication.
• Low energy consumption – operating power below 6VA.
• Compact DIN rail mounting for control and automation panels.
• Changeover 5A / 250V AC contact suitable for contactor control circuits.

• Fixed asymmetry threshold: the 30% protection threshold is not adjustable.
• No phase sequence monitoring: this version does not monitor the L1-L2-L3 phase sequence.
• Neutral connection required: the relay is intended for a 3x380V AC + Neutral system.
• Limited relay contact load: the output contact is rated for up to 5A / 250V AC resistive load, therefore a contactor is recommended for controlling three-phase motors.
• Not suitable for humid environments: the device must be installed in a dry location or in a suitably protected electrical enclosure.

In an industrial system, a three-phase 380V AC electric motor is controlled through a contactor. This phase monitoring relay is installed in the control panel and the three phases and neutral conductor are connected. When all phase voltages are normal and phase asymmetry does not exceed the fixed 30% threshold, the relay OUT indicator lights up and the contactor control circuit can remain active. If the voltage of one phase decreases or increases significantly, the relay deactivates the output and the contactor disconnects the motor. This reduces the risk of three-phase motor overheating and failure caused by unbalanced phase supply.

The relay is designed for a three-phase 3x380V AC network with neutral connection and operates at a frequency of 50/60Hz.

Yes. The device has a fixed 30% phase asymmetry protection threshold.

No. The 30% phase asymmetry protection threshold is fixed.

No. Phase sequence protection is not provided in this version.

Yes. The device is designed for a 3x380V AC + Neutral system and uses the neutral conductor according to the wiring diagram.

If the voltage of one phase increases or decreases beyond the permitted phase asymmetry threshold, the relay output is deactivated and the OUT LED indicator switches off.

The relay output contact is rated for up to 5A / 250V AC resistive load, therefore it is recommended to use the relay output to control the contactor coil for a three-phase motor.

Use the device only according to its intended purpose and the provided wiring diagram. Do not use it in a humid environment. A suitable switch or automatic circuit breaker must be provided in the installation circuit. The disconnecting device must be installed near the controlled equipment, easily accessible to the operator, and clearly marked as the equipment power disconnecting means. Disconnect the electrical power supply before installation or maintenance work.

Disconnect the device from the electrical power supply before carrying out maintenance work. Clean the housing with a dry, soft cloth. Do not use conductive materials, aggressive chemical cleaners, or solvents that may damage the device. After cleaning, check that the relay operates correctly.