What it is and what it does
The Siemens 3RH1140-2BD40 is a SIRIUS auxiliary contactor, size S00, built for switching control circuits — think relay logic, PLC inputs, or contactor coil control in a panel. It carries four normally-open (NO) instantaneous contacts, no delayed or lagging contacts, so it's a straight-up signal repeater, not a timing element. Rated operational current hits 10 A in AC-12 duty (resistive loads at line frequency), and it's rated for switching down to 0.27 A at 220 V DC and up to 6 A at 230 V AC — so it'll handle a mix of coil and signal loads across a typical 24–690 V control panel. Surge voltage resistance is 6 kV, which keeps it safe in industrial environments with moderate transient energy.
Mounting and integration
Mounts via screw or snap-on onto a DIN rail — the 45 mm width and 73 mm depth fit a standard S00 footprint, so it'll drop into any panel already laid out for SIRIUS contactors. Side clearance is zero mm, meaning you can butt it against the next device without derating for airflow. The IP20 front protection means it's fine inside a closed panel but not for washdown areas. Terminals accept solid or stranded wire from 0.25 to 2.5 mm², two conductors per clamp — typical for control wiring. Mounting position is flexible: +/-180° rotation on a vertical surface, plus tilt forward/backward up to +/-22.5°, which helps when you're shoehorning it into a tight cabinet.
Environmental and mechanical specs
Operating temperature range is -25 to +60 °C, storage and transport from -55 to +80 °C — it'll survive a hot truck ride and a cold warehouse. Shock resistance is 10g for 5 ms and 5g for 10 ms, so it won't rattle loose on a vibrating conveyor line. Pollution degree 3 means it's rated for conductive dust and occasional condensation — typical for an industrial control cabinet.