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    DC Voltage Monitoring Relay, Under/Over Voltage, 12V/24V/48V DC

    5 out of 5 based on 2 reviews | Write a review
    DC voltage monitoring relay with 2 C/O contacts (2 Form C or DPDT) provide protection for the equipment from undervoltage and overvoltage in DC circuit 12V, 24V, 36V or 48V, adjustable trip delay time, LED indicator for working state, DIN rail mounting, compact design, good quality and low price.
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    This voltage monitoring relay is applied in the DC circuit for monitoring undervoltage and overvoltage of DC cabinet, battery, electric control system, etc.


    • Compact size in DIN rail mounting
    • DC circuit monitoring of overvoltage and undervoltage
    • Adjustable overvoltage and undervoltage threshold
    • Adjustable trip delay time
    • Powered by the measuring circuit
    • Monitoring relay with 2 C/O contacts (2 Form C or DPDT)
    • 2 LEDs for status indication


    Measuring Circuit DC circuit
    Monitoring Functions Overvoltage, Undervoltage
    Rated Voltage DC 12V DC 24V DC 36V DC 48V
    Voltage Setting Range Undervoltage 10-14V 20-28V 30-42V 40-56V
    Overvoltage 13-17V 26-34V 39-51V 52-68V
    Trip Delay Time 0.1-15s adjustable
    Voltage Hysteresis 3-5% fixed
    Indicators LED indicators for Normal, Trip
    Output Contacts 2 C/O
    Contact Capacity 6A, 250V AC (resistive load)
    Degree of Protection IP 20
    Working Conditions Operating Temperature -25℃~65℃
    Humidity ≤85%RH, non-condensing
    Mechanical Durability 1,000,000 cycles
    Dielectric Strength >2kVAC 1min
    Power Consumption ≤2W
    Mounting 35mm DIN rail
    Weight 130g
    Dimensions (H*W*D) 79*23*79mm

    Wiring Diagram

    DC Voltage Monitor Relay Wiring Diagram

    Monitoring relay contactor wiring

    Dimensions (Unit: mm)

    DC Voltage Monitor Relay Dimension


    DC Voltage Monitoring Relay Details

    Tips: Is an AC Voltage Monitoring Relay Effective?

    1. The voltage monitoring relay must be able to withstand an AC voltage above 450V.
    For 3-phase 380V AC, the grid voltage sometimes has 380V-450V at zero-break, the voltage monitoring relay can be tested before installation, and the relay can be directly connected to the two fire lines for more than 4 hours to confirm whether it can withstand. Of course, it can not ignore whether the voltage monitoring relay can work normally at low voltage. You can use a voltage regulator, and adjust it to about 60V for testing.

    2. The voltage monitoring relay should be able to set the trip protection value according to the rated voltage of the electrical appliance to be protected.
    The setting of the trip protection value must be based on the nameplate identification or instruction manual on the electrical product. Do not set it too high or too low, otherwise the performance and life of the electrical appliance will be greatly reduced or even damaged.

    3. The response speed of the voltage monitoring relay should be fast.
    When the voltage is abnormal, the relay can quickly cut off the power, and the sooner the better.

    4. The voltage monitoring relay should be able to set the delayed closing time according to the characteristics of the electrical appliance being protected.
    This is also very important, because some electrical appliances can not be powered on immediately after power failure; then the delayed closing is a better protection for electrical appliances.

    3-Phase Monitoring Relay Phase Failure & Phase Sequence Testing

    In this video, we will give you a test of ATO 3-phase monitoring relay on phase failure and phase sequence, and the relay does the job at such these cases to protect the motor. In addition, this multi-purpose monitoring relay has other monitoring functions such as undervoltage, overvoltage, voltage unbalance, timer & counter.

    Existing reviews of DC Voltage Monitoring Relay, Under/Over Voltage, 12V/24V/48V DC
    Reliable Monitoring
    The continuous monitoring of DC voltage ensures real-time awareness of the electrical system's status. In the event of voltage deviations beyond the set thresholds, the relay responds promptly, providing an added layer of protection.
    From: Cassian | Date: 23/11/2023
    Was this review helpful? Yes No (0/0)
    Looking for DC voltage monitoring relay
    What is the power consumption of this DC voltage monitoring relay during normal operation and when a under voltage occurrence is in?
    From: Carlos | Date: 27/11/2019
    Was this review helpful? Yes No (0/0)
    ATO Responded
    The power consumption of this relay is ≤2W during normal operation, and when the under-voltage occurs, the power consumption will be smaller than this. And you can adjust the over-voltage and under-voltage threshold in the voltage setting range as you like.
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