What it is and where it fits
The Siemens 3RH1131-1AS00 is a SIRIUS auxiliary contactor in the S00 frame size — the smallest footprint in the SIRIUS contactor family, at 45 mm wide, 57.5 mm tall, and 72 mm deep. It provides three normally open instantaneous contacts (no delayed or lagging switching) and is designed for control-circuit switching, not main motor loads. The S00 frame means it snaps onto a DIN rail or screws to a mounting plate, and the IP20 front protection keeps fingers out of live terminals inside an enclosed panel.
Switching capacity — what the voltage-dependent ratings mean
The 3RH1131-1AS00 carries a rated insulation voltage of 500 V AC (50/60 Hz) and a surge voltage resistance of 6 kV, which puts it in the standard control-circuit insulation class for 400 V line-fed panels. The switching current is voltage-dependent: at 24 V it handles 10 A, at 110 V it drops to 1 A, at 230 V it is rated 6 A, and at 400 V it switches 3 A. At 690 V the rating falls to 1 A. These are the thermal current ratings for the contacts — the actual make/break capacity for inductive loads like contactor coils or relay coils will be lower, so size the load against the AC-15 or DC-13 utilization category if the application involves solenoids or motor contactor coils.
Mounting, wiring, and environment
Mounts in any orientation: the evidence allows ±180° rotation on a vertical surface and ±22.5° forward/backward tilt. The screw terminals accept solid conductors from 0.5 mm² up to 4 mm² (two conductors per terminal for the smaller sizes). Shock resistance is 10g / 5 ms and 5g / 10 ms — adequate for standard industrial panel vibration but not for direct mounting on a high-impact machine frame. Operating temperature range is -25 to +60 °C; storage and transport range is -55 to +80 °C. Pollution degree 3 means it is rated for the conductive-pollution environment typical of control cabinets near production areas.
Contact reliability and endurance
Mechanical endurance is 30 million switching operations typical. Contact reliability is specified as one incorrect switching operation per 100 million operations at 17 V, 1 mA — this is the low-level signal reliability figure, meaning the contacts are gold-flashed or silver-alloy and can handle PLC-level signals without oxidation issues. For a pulp and paper mill running consistency loops or dryer-section controls, that low-level reliability keeps the machine running without nuisance faults from contact oxidation.