What it is and where it fits
The Siemens 3RH1140-1AP00-0TK0 is a SIRIUS auxiliary contactor in size S00, providing four normally-open instantaneous contacts. This is the piece you add alongside a power contactor to multiply signal contacts for PLC inputs, status lamps, or interlocking logic in a motor control center. Rated 10 A in AC-12 duty (resistive loads at 50/60 Hz, up to 230 V) and 10 A at 24 V, it handles typical control-circuit loads without derating. The 10 A AC-12 rating covers most relay and indicator loads found in a panel, so you're not current-limited on the auxiliary side. Mounts via screw or snap-on onto a DIN rail, sized at 45 mm wide by 57.5 mm tall by 72 mm deep — a standard S00 footprint that drops into existing panel layouts without re-spacing. Side clearance is 0 mm, so blocks can sit flush side-by-side. Operating temperature range from -25 °C to +60 °C, with storage down to -55 °C. The IP20 front protection means it's suited for enclosed control panels — not for washdown zones without a cover. Terminals accept solid conductors: 2x (0.5... 1.5 mm²), 2x (0.75... 2.5 mm²), and 2x 4 mm² — this covers standard control wiring from signal loops to heavier interposing relay feeds.
Lifecycle and sourcing posture
For a BOM freeze or spares stocking decision, the 3RH1140-1AP00-0TK0 is a stable line item — no imminent replacement risk. If you already have a panel built around the S00 contactor family, this auxiliary block swaps directly in without wiring changes.
Contact configuration and mechanical endurance
Four instantaneous NO contacts with no leading, lagging, or delayed switching variants — a straightforward block for standard interlocking or feedback. Mechanical endurance is rated at 30 million operating cycles typical, which is generous for a control-circuit device; you'd wear out the main contactor before this auxiliary block. Shock resistance tested to 10g / 5 ms and 5g / 10 ms, suitable for panel mounting on machinery subject to vibration from adjacent contactors or drives. Mounting position is flexible: +/-180° rotation on a vertical surface, and can be tilted forward/backward by +/-22.5° — useful when routing wires in a dense enclosure where the rail orientation is not perfectly vertical.