What it is and what it switches
The Siemens 3RH1131-1HB40 is a SIRIUS coupling relay — a 24 VDC coil, 10 A rated device that switches auxiliary circuits in a control panel. It carries three normally-open instantaneous contacts and zero delayed or lagging switching, so it's a straight on/off signal repeater, not a timing relay. The S00 contactor size keeps the footprint compact at 45 mm wide, 57.5 mm tall, and 72 mm deep.
Key ratings and what they mean for fit
The 10 A at 24 V rating is the headline number — that's the continuous current the contacts can carry at the coil voltage. But the relay also handles 6 A at 230 V, 3 A at 400 V, and 1 A at 690 V, so it's not limited to low-voltage auxiliary loops; it can switch control transformer secondaries or small motor contactor coils at line voltage. The 6 kV surge voltage rating (IEC 60947-1) means the insulation withstands transients common in industrial panels without flashover. Mechanical life is rated at 30 million operations. Contact reliability is specified as one incorrect switching per 100 million operations at 17 V, 1 mA — that's the dry-circuit benchmark for PLC-level signals. If you're switching low-energy digital inputs, this relay won't give you intermittent opens from oxidation.
Where it goes and how it mounts
Mounts via screw or snap-on onto a DIN rail. The mounting position allows +/-180° rotation on a vertical surface and +/-22.5° tilt forward/backward, so orientation in the enclosure is flexible. Pollution degree 3 means it's rated for conductive pollution environments — typical for an IP20 panel interior where some dust and condensation are present. Terminals accept solid wire: 2x 0.5 to 1.5 mm², 2x 0.75 to 2.5 mm², or 2x 4 mm². That covers most control wiring from signal loops to small power feeds. The IP20 front protection means the terminals are finger-safe once installed in an enclosure — standard for panel-mount gear.
Coil power and thermal limits
The DC coil draws 2.3 W closing and 2.3 W holding — same figure, so no power drop after pickup. That's a continuous 2.3 W load on the 24 VDC supply. Operating temperature range is -25 to +60 °C; storage and transport range is -55 to +80 °C. Shock resistance is 10g for 5 ms and 5g for 10 ms, which covers most industrial vibration environments.
Compliance and documentation
RoHS compliant per the substance prohibition date of July 1, 2006. No auxiliary switch extension is available on this base variant — the 3 NO contacts are fixed.