1. Core Functions

• Over-voltage Protection: When the line voltage exceeds the set upper limit (single-phase 270V±5V, three-phase 440V±5V), it trips quickly within ≤100ms to prevent equipment insulation breakdown and burnout.
• Under-voltage Protection: When the line voltage is lower than the set lower limit (single-phase 170V±5V, three-phase 300V±5V), it cuts off the power supply immediately to avoid motor stalling and equipment damage due to overload.
• Neutral Break/Phase Loss Protection: In three-phase four-wire systems, it acts quickly when the neutral line is disconnected or three-phase phase loss occurs, preventing single-phase equipment burnout caused by unbalanced phase voltage.
• Automatic Reclosure: After the voltage returns to normal, it automatically closes with a delay of 5-20 seconds without manual intervention, improving power supply reliability.
• Fault Indication: LED lights clearly display normal, over-voltage, under-voltage and fault status, facilitating quick troubleshooting.
• High-precision Monitoring: Voltage measurement accuracy is ±0.5%, and some models support digital display of voltage, current, power and fault records.

2. Technical Parameters (Universal Type)

3. Product Advantages

• Intelligent and Reliable: MCU control + magnetic latching relay, low power consumption, long service life, accurate action and strong anti-interference ability.
• Full-function Protection: Covering over-voltage, under-voltage, neutral break and phase loss, it provides one-stop solution to voltage abnormal risks.
• Self-resetting and Labor-saving: Automatic delayed reclosure, safer for unattended scenarios (computer room, store, photovoltaic).
• Easy Installation: Standard rail-type design, small size, suitable for distribution boxes, power distribution cabinets and combiner boxes.
• Visual Operation and Maintenance: LED/digital display status, clear fault codes, facilitating quick problem location.

4. Application Scenarios

• Residential Buildings: Protect air conditioners, refrigerators, TVs, computers and other household appliances.
• Commercial Places: Power distribution protection for stores, office buildings, hotels and schools.
• Industrial Equipment: Voltage protection for motors, water pumps, frequency converters and precision instruments.
• Photovoltaic Systems: Front-end protection for photovoltaic combiner boxes and inverters.
• Communication Computer Rooms: Power monitoring and protection for base stations and data centers.

5. Installation and Wiring

Installation Steps

1. After power off, clip the protector into the 35mm DIN rail.
2. Single-phase: Connect incoming L/N to the upper end, and outgoing L/N to the lower end; Three-phase: Connect incoming L1/L2/L3/N to the upper end, and outgoing L1/L2/L3/N to the lower end.
3. Ensure the wiring is firm without looseness, and observe the indicator light status after power on.

Wiring Diagram

6. Frequently Asked Questions (FAQ)

1. What to do if the protector trips frequently? Check if the line voltage is over-voltage/under-voltage for a long time, troubleshoot if the load is short-circuited or overloaded, or adjust the protection threshold (for adjustable models).
2. Why doesn’t it close when the voltage is normal? Check if the wiring is correct and the neutral line is in good contact, and reset the protector (some models require manual reset).
3. Why does it act after neutral break? Neutral break will cause unbalanced phase voltage, and the voltage of single-phase equipment may rise to 380V. The protector cuts off quickly to protect the equipment.
4. Can it be used in DC circuits? This product is for AC use only; DC-specific protectors are required for DC scenarios.

7. Selection Guide

• Single-phase households/stores: Choose 1P+N 32A-63A, suitable for incoming main switch.
• Three-phase industrial/photovoltaic: Choose 3P+N 63A-100A, suitable for power distribution cabinets and combiner boxes.
• High-precision requirements: Choose digital display type, supporting voltage/current/power monitoring and fault records.

8. After-sales Service

• Warranty Period: 2 years, free repair/replacement for non-human damage.
• Technical Support: Provide installation guidance, parameter debugging and fault troubleshooting services.
• Complete Certifications: Passed CQC and CE certifications, complying with international electrical standards.