Auxiliary contactor for control-circuit switching
The Siemens SIRIUS 3RH1131-1KG40-0LA0 is a size S00 auxiliary contactor with three normally open instantaneous contacts, designed for switching control loads in industrial panels. It carries a rated value of 125 V and delivers 10 A at 24 V, 6 A at 230 V, and 3 A at 400 V — the current drops predictably with voltage, so size the contact for the actual control voltage on your circuit. Mounting is via screw or snap-on onto a DIN rail, with a 45 mm width that fits the S00 footprint common across the SIRIUS contactor family. The front face carries IP20 protection, meaning it's safe for finger contact inside an enclosed panel but not for washdown environments.
Contact ratings and coil draw
The magnet coil draws 11 W on closing and holds at 4 W DC — the holding power is low enough that a 24 VDC supply with modest headroom can keep it sealed continuously. Surge voltage resistance is rated at 6 kV, and a built-in varistor suppresses switching transients across the coil. Contact reliability is specified as one incorrect switching operation per 100 million operations at 17 V, 1 mA — that's the dry-circuit threshold for low-energy signals. For typical pilot-duty loads at 24 V and above, mechanical life reaches 30 million operations.
Environmental and mechanical limits
Operating temperature spans -40 to +70 °C, with storage and transport extending to -55 to +80 °C. Shock resistance is 10g for 5 ms and 5g for 10 ms, and the mounting position allows +/-180° rotation on a vertical surface plus +/-22.5° forward/backward tilt — useful when panel layout forces an unconventional orientation. Pollution degree 3 means the contactor is rated for industrial environments with conductive pollution or dry non-conductive pollution that becomes conductive due to condensation — standard for unsealed control cabinets.