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    3 Phase Voltage Monitor Relay, 3-wire 127V-265V/4-wire 220V-460V

    5 out of 5 based on 1 reviews | Write a review
    The three-phase voltage monitoring relay has SPDT (2 C/O) contacts, accurate pressure measurement, and is suitable for quickly cutting off or connecting the circuit when the power supply voltage exceeds or falls below the set range for 3-wire AC 127V-265V/ 4-wire AC 220V-460V to ensure the safe and reliable operation of the power system. The 3-phase relay is equipped with LED lights to indicate the working status and is lightweight and easy to install.
    SKU: ATO-MR-GRV810
    30-day Returns
    Free Shipping
    Delivery date: 6-12 days

    The 3-phase voltage monitor relay has an LED indicator to indicate the working status, with a normal/ emergency power switch, which can effectively detect voltage imbalance and protect the equipment from accidents caused by the reverse operation. There are two open and two closed contacts, and the flame-retardant shell is reinforced. This three-phase relay has 8 rated voltages that are adjustable, with a wide range of applications, and can be used for field equipment, agricultural equipment, refrigerated vehicle lights, and mobile equipment connection control.


    • Controls its own supply voltage (True RMS measurement).
    • Set 8-level rated operating voltage through the knob.
    • Set the reset delay time through the knob.
    • 2C/O output.
    • Measuring frequency range: 45Hz-65Hz.
    • Voltage measurement accuracy <1%.
    • Relay status is indicated by LED.
    • 2-MODULE, DIN rail mounting.
    • Ultra-small size, only 36mm width, 35mm rail installation.


    Model ATO-GRV8-10M265 ATO-GRV8-10M460
    Function Monitor L-N voltage (3-phase 4-wire system) Monitor L-L voltage (3-phase 3-wire)
    Monitoring Terminals L1-L2-L3-N L1-L2-L3
    Supply Terminals L1-L2-L3-N L1-L2-L3
    Voltage Range 127-132-138-220-230-240-254-265 (P-N) 220-230-240-380-400-415-440-460 (P-P)
    Rated Surge Withstand Voltage 2.5kV
    Rated Insulation Voltage 500
    Rated Supply Frequency 45Hz-65Hz
    Measuring Range 101V-318V 176V-552V
    Threshold Adjustment Voltage 2%-20% of unselected
    Adjustment of Asymmetry Threshold 5%-15%
    Hysteresis 2%
    Phase Failure Voltage 70% of the rated voltage
    Supply Indication Green LED
    Time Delay Adjustable 0.1 s - 10 s, 10%
    Measurement Error ≤1%
    Run-up Delay at Power-up Adjustable 0.1 s - 10 s, 10%
    Konb Setting Accuracy 10% of scale value
    Reset Time Adjustable 0.1 s - 10 s, 10%
    Temperature Coefficient 0.05%°C, at=20°C (0.05%°F, at=68°F)
    Output 2×SPDT
    Current Rating 8A/AC1
    Switching Voltage 250VAC/ 24VDC
    Min. breaking Capacity DC 500MW
    Output Indication Red LED
    Mechanical Life 1×107
    Electrical Life (AC1) 1×105
    Operating Temperature -20°℃ to +55℃ (-4°F to 131°F)
    Storage Temperature -35℃ to +75℃ (-22°F to 158°F)
    Mounting/ DIN rail Din rail EN/ IEC 60715
    Protection Degree lP40 for front panel/ IP20 terminals
    Installation 35mm rail installation
    Operating Position Any
    Overvoltage Cathegory III.
    Pollution Degree 2
    Max. cable Size (mm2) Solid wire max.1×2.5 or 2×1.5/ with sleeve max.1×2.5 (AWG 12)
    Dimensions 90mm×36mm×64mm
    Weight 100g
    Standards EN 60255-1, lEC60947-5-1

    Wiring Diagram

    3-phase voltage monitor relay phase wiring

    Panel Diagram

     3-phase voltage monitor relay phase panel

    Function Diagram

    • Phase failure and phase sequence function diagram

    3-phase voltage monitor relay phase failure and sequence

    • Asymmetry function diagram

    3-phase voltage monitor relay phase asymmetry function

    To: Overvoltage threshold tripping delay.
    Tu: Undervoltage threshold tripping delay.
    Ta: Asymmetry threshold tripping delay.
    Tr: Power-up delay.

    • Overvoltage and undervoltage function diagram

     3-phase voltage monitor relay phase overvoltage and undervoltage

    Dimensions (mm)

    3-phase voltage monitor relay dimension mm

    Tips: Maintenance of 3-Phase Voltage Monitor Relay

    Use a soft brush or air blow gun to remove dust from the outside and inside of the relay and maintain a dry and clean environment.

    Tighten the screws and regularly replace aging parts such as worn contacts or coils to keep the relay in normal working condition. Regularly check the contact point pressure and arc marks of the relay to ensure that the contact point pressure is appropriate and there is no abnormal wear or corrosion.

    Ensure that the power supply voltage is stable to prevent the relay from bearing a current load exceeding the rated capacity to prevent overload damage. The working environment temperature should be appropriate. If it exceeds the specified temperature range, heat dissipation measures need to be taken.

    Existing reviews of 3 Phase Voltage Monitor Relay, 3-wire 127V-265V/4-wire 220V-460V
    Useful 3 Phase Voltage Monitor Relay
    I referred to the data on many pages before deciding to buy this three-phase voltage monitoring relay, because the original electrical wiring in the house was installed many years ago when I moved in, and it is not easy to change it over time. However, because I recently purchased a solar panel, I decided to install a monitor for safety reasons. This 3-phase voltage relay can monitor the AC voltage before connecting to the grid, ensure voltage stability during the switching process, and prevent equipment damage or safety accidents due to voltage fluctuations. The high quality of the relay saved me a lot of trouble later.
    From: Lorraine | Date: 06/06/2024
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