What it is and what it does
The Siemens 3RH1122-1AP00-1AA0 is a SIRIUS auxiliary contactor in the size S00 frame. It provides 2 normally open instantaneous contacts for switching control circuits, rated at 10 A maximum in AC-12 duty (resistive loads at 50/60 Hz). The 10 A AC-12 figure is the thermal current rating that governs continuous current through the contacts — not a motor-switching number, so size the load accordingly.
Mounting and integration
Mounts via screw or snap-on onto a DIN rail. The 45 mm width and 72 mm depth fit the standard S00 footprint — it occupies one 45 mm-wide module position in the panel. Standing orientation on a horizontal mounting surface is specified. Solid conductors accepted: 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or 2x 4 mm². That covers most control-circuit wiring from signal-level up to 4 mm² power feeds.