What it is and what it does
The Siemens SIRIUS 3RH1431-1AU00 is a size S00 auxiliary contactor — three normally-open instantaneous contacts, no delayed or lagging switching, no make-before-break. It's the signal-level switching block in a motor control center: the part that tells the PLC an interlock is made or that a main contactor has pulled in.
Key ratings and what they mean for fit
Three NO contacts rated for switching: 10 A at 24 V, 6 A at 230 V, 3 A at 400 V, and 1 A at 690 V — these are the AC-15 / DC-13 signal-switching curves, not motor-load currents. The 6 kV rated surge voltage resistance means it handles the transient spikes common on 400 V industrial panels without flashover. IP20 on the front (finger-safe) is standard for enclosed panels; no washdown rating here.
Mounting and wiring
Screw and snap-on mounting onto DIN rail — the S00 footprint is compact at 90 mm wide × 57.5 mm deep × 72 mm tall. Wire capacity is generous for its size: accepts 2× 0.5–1.5 mm², 2× 0.75–2.5 mm², or 2× 4 mm² solid. Mounting position allows ±180° rotation on vertical surfaces and ±22.5° tilt forward/backward — useful when panel layout forces an odd orientation.
Environmental and compliance
Rated for pollution degree 3 (conductive pollution typical in industrial enclosures). Operating temperature range -25 to +60 °C; storage and transport down to -55 °C and up to +80 °C. Shock resistance tested at 10g / 5 ms and 5g / 10 ms. Contact reliability is specified as one incorrect switching operation per 100 million operations at 17 V, 1 mA — relevant for low-energy signal circuits where oxide films can cause intermittent opens.