The Siemens 3RH1122-2AN20 is a SIRIUS auxiliary contactor in the compact S00 frame (45 mm wide, 60 mm tall, 73 mm deep) — sized for control-circuit switching in motor starter and relay logic panels. It carries a 10 A rated value at 24 V, with the contact reliability spec of one incorrect switching per 100 million operations at 17 V, 1 mA, so it's trustworthy for low-energy PLC inputs and signal-level loads.
Fastens with screw or snap-on onto DIN rail — no tools needed for the snap-on, which is handy if you're swapping it in a live panel. The solid terminal accepts 0.25 to 2.5 mm² conductors (2x per clamp).
Electrical ratings and environment
Shock resistance is 10g / 5 ms and 5g / 10 ms, so it holds up in machinery with vibration.