The Siemens SIRIUS 3RH1122-1KG40-0LA0 is an auxiliary contactor in size S00, carrying 2 normally open and 2 normally closed instantaneous contacts. It mounts via screw or snap-on to a DIN rail, occupying 45 mm width and 72 mm depth on the panel. The front face is IP20 rated, suitable for enclosed control panels where accidental finger contact is prevented.
Contact ratings and switching capacity
Rated at 125 V with an initial value of 0.7 and full-scale of 1.25, the contactor's thermal current at 24 V is 10 A, dropping to 1 A at 110 V, 0.27 A at 220 V, 6 A at 230 V, 3 A at 400 V, 2 A at 500 V, and 1 A at 690 V. These values reflect the AC-1 resistive load curve; the 10 A at 24 V covers the common control-circuit voltage in many panels, while the 1 A at 690 V is the ceiling for higher-voltage auxiliary circuits. The varistor surge suppressor is built in, clamping voltage transients from inductive loads like contactor coils or solenoid valves.
Mechanical endurance and environmental limits
Mechanical life is rated at 30 million switching operations typical, with a contact reliability of one incorrect operation per 100 million at 17 V, 1 mA — relevant for dry-circuit or low-energy signal switching where oxide films on contacts can cause intermittent faults. Shock resistance is 10g / 5 ms and 5g / 10 ms, and the operating temperature range is -40 to +70 °C, storage and transport -55 to +80 °C. Pollution degree 3 means it tolerates conductive pollution or dry non-conductive pollution that becomes conductive due to condensation — standard for industrial control panels not in sealed enclosures.
Mounting and wiring
Mounting position allows +/-180° rotation on a vertical surface, plus +/-22.5° tilt forward and backward — useful when fitting into tight or angled sub-panels. Solid conductors accepted: 2x 0.5 to 1.5 mm², 2x 0.75 to 2.5 mm², and 2x 4 mm². The screw terminals accept ferruled or solid wire; the spring-cage variant is not this order code. Coil closing power is 11 W DC, holding power 4 W DC — the holding power is roughly one-third of the inrush, so the coil driver must handle the peak but the steady-state load is light. Surge voltage resistance is 6 kV, matching the impulse withstand for basic insulation coordination in 400 V systems.
Lifecycle and compliance
The lifecycle stage is marked as current. The part complies with RoHS substance prohibitions dated July 1, 2006. The SIRIUS brand is Siemens' modular contactor and control gear family, widely used in panel building and machine control. The auxiliary switch extension is possible, allowing field addition of extra contact blocks without removing the base unit.