What it is and where it fits
The Siemens 3RH1122-2AP00 is a SIRIUS auxiliary contactor, size S00, designed to mount alongside SIRIUS contactors in a control panel. It provides two normally-open instantaneous contacts for feedback or interlock circuits. The 45 mm width and screw-and-snap-on mounting mean it clips onto a DIN rail or screws into a panel without extra bracketry. Rated 10 A at 24 V in AC-12 duty (resistive loads), it handles signal-level switching for PLC inputs, relay coils, or indicator lamps. The contacts are rated for 50/60 Hz operation, with a rated insulation voltage of 230 V at 50 Hz and 230 V at 60 Hz.
Mounting and environmental fit
The contactor mounts on a vertical surface with ±180° rotation possible, and can be tilted forward or backward by ±22.5° — handy when you're squeezing it into a crowded gland plate. The front face carries IP20 protection; the wiring terminals accept 0.25 to 2.5 mm² solid or stranded conductors. Operating temperature spans -25 to +60 °C, storage and transport from -55 to +80 °C. Shock resistance is 10g for 5 ms and 5g for 10 ms, so it'll survive the ride on a lube route or a conveyor line.
What the ratings mean for your panel
The AC-12 rating of 10 A at 24 V is the resistive-load maximum — don't push inductive loads (like small contactor coils) past the derated AC-15 curve. The 2 NO contacts are instantaneous (no make-before-break or delayed switching), so they close and open at the same time as the main contactor's armature. Pollution degree 3 means it's rated for industrial environments with conductive dust or occasional condensation — no extra conformal coating needed for most cabinets.