22.5 mm control relay with adjustable timing
The RM4TA31 is a Harmony RM4-T series industrial measurement and control relay from Schneider Electric, packing a 2 C/O output contact set into a 22.5 mm wide DIN-rail housing. The adjustable time delay spans 0.1 to 10 s, with a fixed 50% asymmetry hysteresis that governs the reset ratio — meaning the relay drops out at 50% of the pickup threshold, a non-negotiable parameter for sequence timing in pump control or conveyor interlock circuits. Rated for pollution degree 3 per IEC 60664-1 and overvoltage category III, it fits into industrial panels where transient immunity matters — the 2.5 kV dielectric test voltage confirms basic insulation between coil and contacts. The 90/10 silver-nickel contacts handle 250 V AC switching with a 10 mA minimum switching capacity at 12 V, so it reliably wets low-signal loads without contact oxidation over the 30 million-cycle mechanical endurance.
Current production — sourcing posture
Listed as current production (active lifecycle stage).
Panel fit and environmental tolerance
Depth is 80 mm (3.1 in), width 22.5 mm (0.9 in), height 78 mm (3.07 in) — the 22.5 mm footprint occupies one standard DIN-rail pitch, with 2.5 nine-mm pitches consumed. IP20 at the terminals, IP50 on the casing means it is protected against tools and wires but not washdown; install inside a sealed enclosure in wet environments. Operating position is any without derating, and the shock resistance is 15 gn for 11 ms per IEC 60068-2-27, so it survives moderate industrial vibration and impact. Supply frequency is 50/60 Hz ±5 %, with a 650 ms power-up delay before the output relay energises — this prevents nuisance tripping on brownout recovery. Time delay drift is ≤0.5 % within the measuring range, and the maximum measuring cycle is 80 ms, so the relay updates its output state within one mains cycle for most line frequencies.
Compliance and documentation
CE marked under the Low Voltage Directive 73/23/EEC and EMC Directive 89/336/EEC. Designed to IEC 60255-6 (measuring relays and protection equipment). Pollution degree 3 and overvoltage category III per IEC 60664-1. Screw terminals accept 2 x 1.5 mm² flexible with ferrule or 2 x 2.5 mm² flexible without ferrule; tightening torque range is 0.6 to 1.1 N·m.