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.
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. If you're switching low-energy digital inputs, this relay won't give you intermittent opens from oxidation.
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. Shock resistance is 10g for 5 ms and 5g for 10 ms, which covers most industrial vibration environments.
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.