The Siemens 3RH2122-2AB00-ZX95 is a SIRIUS auxiliary contactor, size S00, with 2 instantaneous NO contacts. It switches control signals and low-power loads in a panel, rated at 10 A at 24 V AC/DC and 10 A at 230 V, with a stepped derating curve up to 1 A at 690 V. The 10 000 operations-per-hour DC switching frequency means it handles high-speed cycling on a sorting line or a conveyor interlock without wearing out the contacts early. The 45 mm width and 73 mm depth fit the standard S00 footprint, and the screw and snap-on mounting onto a 35 mm standard mounting rail means it clips into the same DIN rail as the main contactor block. Mounting position is flexible — +/-180° rotation on a vertical surface, plus +/-22.5° tilt forward and backward — so it fits in a tight enclosure without fighting the rail orientation.
Snap it onto the 35 mm DIN rail beside the main contactor. The 2 NO contacts are electrically isolated from the coil — wire them as a feedback signal to the PLC or as a seal-in for the motor starter. The screw terminals accept 2x (0.5 to 4 mm²) solid or stranded, so standard panel wire fits without ferrule adapters. Clearance: 10 mm upwards, 10 mm forwards, 10 mm downwards, 6 mm at the side — no need to oversize the enclosure for this one component.
Operating temperature range is -25 to +60 °C, storage range -55 to +80 °C — rated for the inside of a non-conditioned panel in a mill or a mine. RoHS compliance date is 2009-10-01, so it meets the EU substance restrictions for new installations.