The Siemens 3RH1122-1BF40-ZX95 is a SIRIUS auxiliary contactor in size S00, designed for switching control and signaling circuits in industrial panels. It carries 2 normally-open and 2 normally-closed instantaneous contacts, with a 110 V DC coil that draws 3.2 W closing and holding power. The contactor is rated for 10 A at 24 V, 1 A at 110 V, and derates to 0.27 A at 220 V and 6 A at 230 V — covering both low-voltage control loops and higher-voltage interlock circuits. The IP20 front protection keeps panel-side fingers safe during maintenance.
Mounts via screw and snap-on to a DIN rail; the 45 mm width and 57.5 mm height fit standard S00 contactor spacing. The mounting position allows ±180° rotation on a vertical surface and ±22.5° forward/backward tilt, so it can be oriented to match existing wiring troughs. Solid connections accept 2x (0.5–1.5 mm²), 2x (0.75–2.5 mm²), or 2x 4 mm² — spring-cage terminals would be faster, but the screw clamp holds well under vibration. Depth of 72 mm leaves room for front-accessible wiring without crowding the gland plate.
Contact reliability is specified as one incorrect switching operation per 100 million operations at 17 V, 1 mA — meaning it handles dry switching (low-current signal contacts) without the oxide-film issues that plague standard power relays. Mechanical life is typical 30 million operations. Shock resistance is 10g at 5 ms and 5g at 10 ms, adequate for most conveyor and pump panels.