Voltage monitoring relay with adjustable trip thresholds
The RM4UA31Q is a voltage measurement relay from the Zelio Control range, designed for overvoltage or undervoltage detection in industrial control circuits. It monitors a single-phase AC supply and trips its output relays when the measured voltage crosses the set threshold. Two key adjustments let you tune the response: hysteresis is settable from 5 to 30 % of the threshold voltage, and the output time delay is adjustable from 0.05 to 30 s. This means you can prevent nuisance tripping on transient dips or surges while still catching sustained faults.
Contact ratings and switching capacity
The relay provides two changeover (2 C/O) output contacts with silver-nickel (90/10) material, rated for 3 A at 250 V AC-15 per IEC 60947-5-1 — the standard for switching electromagnetic loads like contactor coils and solenoid valves. At 24 V DC-13 (switching DC solenoids), the rating is 2 A. Minimum switching capacity is 10 mA at 12 V, which covers PLC digital inputs and low-power signal circuits. The maximum switching voltage is 440 V AC, so the contacts can handle line-voltage control circuits in most panel environments.
Compliance and environmental ratings
Designed to EN/IEC 60255-6 (measuring relays and protection equipment), the RM4UA31Q carries a dielectric test voltage of 2.5 kV and withstands a 4.8 kV non-dissipating shock wave. Pollution degree 3 per IEC 60664-1 means it is rated for industrial environments with conductive pollution. EMC compliance covers electrostatic discharge (6 kV contact / 8 kV air, level 3 per IEC 61000-4-2) and fast transients at 2 kV (level 3 per IEC 61000-4-4). The enclosure is IP50; the terminals are IP20 — suitable for installation inside a clean, dry panel.