Auxiliary contactor for SIRIUS S00 — 3RH1122-1BC40
The Siemens SIRIUS 3RH1122-1BC40 is an auxiliary contactor in the S00 frame size, designed for switching control and signalling circuits in motor starter and contactor assemblies. It carries a maximum operating current of 10 A at AC-12 duty — that's the resistive load rating for control transformers and indicator lamps, not motor inrush. The DC coil pulls 3.2 W on closing and holds at the same 3.2 W, so the control transformer sizing is straightforward: no inrush spike to derate for. Mounting is screw or snap-on onto DIN rail, with a 45 mm width that fits standard S00 panel layouts.
What the ratings mean for fit
The AC-12 rating of 10 A is the key selection figure — it governs switching of resistive control loads. For inductive loads like contactor coils or solenoid valves, you'd derate per the manufacturer's curve; the listed values at 230 V (6 A) and 400 V (3 A) give a rough guide for mixed-duty circuits. The 24 VDC coil is continuous-rated at 3.2 W, so the power supply must sustain that hold current without droop. Operating temperature spans -25 to +60 °C, which covers most panel environments short of a foundry floor. Shock resistance at 10g / 5 ms and 5g / 10 ms means it survives shipping and moderate machine vibration, but not hammer-mill duty.
Panel integration and wiring
Screw and snap-on mounting onto DIN rail. The terminal block accepts solid conductors: 2x 0.5...1.5 mm², 2x 0.75...2.5 mm², or 2x 4 mm².