What it is and where it fits
The Siemens 3RH1122-1AN00 is a SIRIUS auxiliary contactor, size S00, carrying four normally open instantaneous contacts. It is designed to extend the control-circuit switching capacity of a main contactor or to build interlocking logic in a motor control center. The S00 frame size matches the smallest Siemens contactor footprint, so it mounts directly alongside or on top of a S00 power contactor without extra panel space.
Key ratings and what they mean for your circuit
Each contact is rated 10 A in AC-12 duty (resistive control loads) at 24 V, and derates to 6 A at 230 V, 3 A at 400 V, and 1 A at 690 V. The AC-12 rating is the relevant one for switching solenoid valves, relay coils, and PLC inputs — not motor currents. The surge voltage resistance of 6 kV means the contact gap and insulation withstand typical switching transients in an industrial panel without flashover.
Mounting and integration
Mounts by screw or snaps onto a 35 mm DIN rail. The mounting position is flexible: ±180° rotation on a vertical surface and ±22.5° tilt forward/backward, which helps when routing wires in a crowded enclosure. The front face carries IP20 finger protection; the sides and back rely on the enclosure for protection. Pollution degree 3 means it is rated for conductive pollution typical in control panels — no conformal coating required for normal industrial environments.
Wire termination and panel fit
The screw terminals accept two conductors per clamp: 0.5 to 1.5 mm², 0.75 to 2.5 mm², or a single 4 mm². The 45 mm width and 57.5 mm height match the S00 contactor envelope; the 72 mm depth leaves clearance for front-accessible wiring. At 2 000 m maximum operating altitude, no derating is needed for most sites.
Environmental limits and mechanical life
Operates from -25 °C to +35 °C, stores and transports from -55 °C to +80 °C. Shock resistance is 10g at 5 ms and 5g at 10 ms, which covers normal shipping and panel-door impacts. The typical mechanical life of the S00 contactor family is 30 million operations — the auxiliary block shares that endurance when switched unloaded or within its rated current.