What it is and what it does
The Siemens 3RH1140-1BA40 is a SIRIUS auxiliary contactor in size S00, carrying four normally-open instantaneous contacts. It mounts via screw or snap-on to DIN rail, with a 45 mm width that fits standard panel layouts. The front face is IP20 rated — protected against finger contact but not sealed against dust ingress, so plan for a clean enclosure if the panel lives in a gritty environment. Rated operating current hits 10 A in AC-12 duty (resistive loads at line frequency). For inductive switching at higher voltages, the contactor is rated 6 A at 230 V, 3 A at 400 V, 2 A at 500 V, and 1 A at 690 V. The DC coil draws 3.2 W both on pickup and hold — no power reduction after sealing, so factor that into the control transformer sizing.
Mounting and environment
Screw and snap-on mounting onto 35 mm DIN rail. The mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward — useful when the panel layout forces an odd angle. Zero spacing required at the side, so you can pack contactors tight on the rail. Operating temperature spans -25 to +60 °C; storage and transport range is -55 to +80 °C. Pollution degree 3 means it tolerates conductive dust and occasional condensation — typical for industrial control panels, but not for direct washdown zones. Shock resistance is 10g / 5 ms and 5g / 10 ms, enough for most machine-mounted applications. Wire capacity accepts 2x conductors from 0.5 to 1.5 mm², 2x from 0.75 to 2.5 mm², or 2x 4 mm² solid. That covers common control wiring sizes without needing ferrules, though ferruled stranded wire is fine within the same cross-sections.