The Siemens 3RH1140-1AT60 is a SIRIUS auxiliary contactor in size S00, carrying 4 normally-open instantaneous contacts rated 10 A at AC-12. It snap-mounts onto a DIN rail or screws to a panel backplate — the 45 mm width fits standard S00 busbar and enclosure layouts. The IP20 front keeps live parts behind the panel door; this is a control-circuit switching block, not a power contactor, so it handles signal-level loads and pilot duty for larger contactors or relays.
Ratings and what they mean for your panel
The 10 A AC-12 rating governs resistive pilot-duty loads. Contact reliability guarantees fewer than one incorrect switching event per 100 million operations at 17 V, 1 mA. For inductive DC switching, the 24 V rating is 10 A, but the curve drops sharply: 1 A at 110 V, 0.27 A at 220 V. If you are switching a DC solenoid or brake coil at 110 V, the 1 A limit is the binding constraint — not the AC-12 figure. The 4 NO contacts are all instantaneous (no leading, lagging, or delayed switching). That is four isolated sets for interlocking, status feedback, or permissive circuits. The auxiliary switch extension option allows field-fit side-mount blocks if you need more.
Mounting and environment
Screw and snap-on mounting onto DIN rail. Mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward. Degree of pollution 3 means it is rated for conductive pollution in industrial atmospheres (condensation, occasional dust). The IP20 front protects against finger contact but not water ingress — this is a dry-panel part, not a washdown component.