The Siemens SIRIUS 3RH2122-2LJ80-0LA0 is an auxiliary contactor in size S00, built for control-circuit switching in motor starter and contactor assemblies. It carries two normally-open and two normally-closed instantaneous contacts, rated 10 A at 230 V AC and 10 A at 24 V DC, with a coil draw of 13 W DC at pickup. The 72 V DC coil includes a factory-fitted varistor surge suppressor, which clips the inductive kickback — no external flyback diode needed on the coil wiring.
Contact ratings and switching life
The contacts are rated across the full voltage spectrum: 10 A at 24 V, 4.7 A at 60 V, 3 A at 110 V, 1.2 A at 220 V, 10 A at 230 V, 3 A at 400 V, 0.5 A at 440 V, 2 A at 500 V, 0.26 A at 600 V, and 1 A at 690 V. The AC switching frequency reaches 10,000 operations per hour; DC switching is limited to 7 to 20 ms per cycle. Mechanical life is rated at 30,000,000 operations typical — this is a contactor you install and forget for the life of the panel. Arcing time runs 10 to 15 ms. The degree of pollution is 3, meaning the contactor is rated for conductive pollution environments typical of industrial control panels without hermetic sealing. Operating temperature spans -40 to +70 °C; storage range is -55 to +80 °C.
Mounting and clearances
Mounts via screw or snap-on onto 35 mm DIN rail. The mounting position allows +/-180° rotation on a vertical surface and +/-22.5° tilt forward or backward. Required clearances: 10 mm upwards, 10 mm forwards, 10 mm downwards, and 6 mm at the sides. With a width of 45 mm, depth of 116 mm, and height of 70 mm, it fits the standard S00 footprint. Terminals accept 2 x (0.5 to 4 mm²) solid or stranded wire. The fastening method is screw and snap-on onto 35 mm DIN rail, so it drops onto the same rail as the main contactor without extra hardware.