What this part is and what it does
The Siemens SIRIUS 3RH1122-2KF40-0LA0 is an auxiliary contactor, size S00, designed for switching control circuits in industrial panels. It carries 2 normally-open and 2 normally-closed instantaneous contacts, rated for switching at 110 V DC with a coil that draws 11 W on closing and 4 W holding. The integrated varistor surge suppressor handles the coil's inductive kick, rated for surge voltage resistance of 6 kV.
Mounting and integration
Mounts via screw or snap-on onto a DIN rail. The 45 mm width and 123 mm depth fit standard S00 panel layouts. Terminal capacity accepts 0.25 to 2.5 mm² solid or stranded wire — 2 conductors per clamp. Mounting position allows ±180° rotation on a vertical surface, plus ±22.5° tilt forward/backward, giving flexibility in tight enclosures. IP20 on the front means it's protected against finger contact but not washdown — suitable for dry, enclosed control cabinets.
Contact ratings and switching capability
Contact reliability is rated at one incorrect switching operation per 100 million cycles at 17 V, 1 mA — suitable for low-energy PLC or sensor signals. The AC-15 / DC-13 switching capacity varies by voltage: at 24 V the contacts switch 10 A, at 110 V they switch 1 A, at 230 V they switch 6 A, and at 400 V they switch 3 A. These ratings govern the actual load the contacts can break under inductive or resistive conditions. Pollution degree 3 means it's rated for industrial environments with conductive pollution.
Environmental and compliance
Operating temperature range is -40 to +70 °C; storage and transport range is -55 to +80 °C. Shock resistance is 10g for 5 ms and 5g for 10 ms. RoHS compliance date is July 1, 2006 — the part meets the original RoHS directive.