What It Is and Where It Fits
The Siemens 3RH1122-1HE40 is a SIRIUS coupling relay designed for switching auxiliary circuits in control panels. It mounts via screw or snap-on onto a DIN rail, occupying the S00 contactor footprint — 45 mm wide, 57.5 mm tall, 72 mm deep — so it drops into the same rail space as a size S00 contactor without re-spacing the enclosure layout.
Key Ratings and What They Mean for Fit
Rated at 60 V, the relay carries a 10 A continuous current at 24 V — enough for pilot lamps, PLC digital outputs, or small solenoid valves in a 24 VDC control loop. At 230 V the rating drops to 6 A, and at 400 V to 3 A, following the thermal derate for higher voltages. The 2 NO instantaneous contacts handle make-and-break without delayed or lagging switching, so the relay responds immediately to the coil signal. Surge voltage resistance is rated at 6 kV, which means the relay withstands transient overvoltages common in industrial control circuits without flashover — relevant for panels fed from long cable runs or near motor drives. The coil draws 2.3 W closing and holding on DC, a constant load that the PLC output or control transformer must budget for. Wire termination accepts solid conductors from 0.5 mm² up to 4 mm² (or 2x 1.5 mm², 2x 2.5 mm²), with AWG equivalents of 20–16 and 18–14 for twin wires, and 12 AWG for a single. The screw terminals are sized for standard control wiring, so no special ferrules or crimp tools are required for panel wiring.
Mounting and Environmental Limits
Mounting position is flexible: the relay can be rotated ±180° on a vertical surface and tilted forward/backward ±22.5°, which simplifies layout in crowded enclosures. Operating temperature range is -25 to +60 °C, with storage and transport tolerance from -55 to +80 °C — the relay survives desert sun in a non-climate-controlled warehouse or a cold truck ride. Shock resistance is 10g for 5 ms and 5g for 10 ms, adequate for machine-mounted panels near presses or conveyors. IP20 on the front means the relay is protected against finger contact but not against water ingress — it belongs inside a sealed enclosure, not on an open panel face. Pollution degree 3 (conductive pollution or dry non-conductive pollution that becomes conductive due to condensation) is the rating, so the relay is suited for industrial environments where dust and humidity are present but not extreme.