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    Single Phase Voltage Monitoring Relay, 12V/24V DC, 110V/220V AC

    High-quality and affordable single phase voltage monitoring relay providing 12V/24V/48V DC and 110V/220V/240V AC, equipped with an LED indicator and high contact capacity. Specially designed for fixed overvoltage protection, the 1-phase voltage monitoring relay operates stably with a 1NO+1NC contact configuration. The small 12V DC relay reliably functions in ambient temperatures ranging from -20°C to +55°C. The single phase monitoring relay is the best choice for voltage monitoring applications.
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    Delivery date: 6-12 days

    The single phase monitor relay is used to protect electrical equipment and motors from overvoltage and undervoltage, while also supporting the switching between normal and emergency power supplies. The product is made of flame-retardant materials and has passed burn tests, ensuring no particle drop and rapid extinction after flame. The relay offers multiple voltage options and can be directly installed in distribution boxes and is widely applicable in scenarios such as household appliance protection, industrial automation, renewable energy systems, emergency power supply systems, and medical equipment. It provides reliable voltage monitoring and protection, ensuring the safe operation and longevity of your equipment.


    • Controls single phase relay's own supply voltage (True RMS measurement)
    • Users may select operation mode through the knob
    • Voltage measurement accuracy≤1%
    • Relay status is indicated by LED
    • Ultra-small size, only 18mm width, 35mm DIN rail mounting


    Model ATO-GRV8-01
    Phase 1 Phase
    Function Monitoring voltage
    Supply terminals A1-A2
    Rated supply voltage DC12V, AC/DC24V-48V, AC/DC110V-240V, AC220V
    Rated supply frequency 45Hz-65Hz,0
    Rated insulation voltage 460V
    Hysteresis 5%-20%
    Supply indication green LED
    Time delay Adjustable 0.1s-10s,10%
    Measurement error ≤1%
    Run up delay at power up 0.5s time delay
    Knob setting accuracy  10% of scale value
    Reset time 1000ms
    Temperature coefficient 0.05%/°C, at=20°C (0.05%/°F, at=68°F)
    Output 1×SPDT
    Current rating 10A/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°C to +55°C (-4°F to 131°F)
    Storage temperature -35°C  to +75°C  (-22°F to 158°F)
    Mounting/DIN rail Din rail EN/IEC 60715
    Protection degree IP40 for front panel / IP20 terminals
    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 90×18×64mm
    Weight 59g
    Standards EN60255-1, IEC60947-5-1

    Functions Diagram

    Single Phase Voltage Monitoring Relay Functions Chart 

    Wiring Diagram

    Single Phase Voltage Monitoring Relay Wiring Chart

    Dimensions (mm)

    Single Phase Voltage Monitoring Relay Dimensions Chart

    Tips: What does a single phase voltage monitoring relay do?

    1. Monitors Voltage Levels: A single phase voltage monitoring relay continuously monitors the voltage in a single-phase electrical system, ensuring it stays within safe limits to protect connected equipment.

    2. Protects Against Voltage Fluctuations: The relay provides protection by disconnecting the load or triggering an alarm if the voltage exceeds or drops below preset thresholds, preventing potential damage to electrical devices.

    3. Wide Voltage Compatibility: These relays are compatible with various voltage ranges, such as 12V/24V DC and 110V/220V AC, making them versatile for different applications.

    4. Critical for Sensitive Equipment: They are essential for protecting sensitive equipment like HVAC systems, lighting, and power supplies, which can be affected by voltage fluctuations, ensuring their longevity and proper function.

    5. Adjustable Trip Protection: The relay allows setting the trip protection value according to the rated voltage of the equipment, based on the nameplate or manual instructions, to avoid over or under-protection.

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