What it is and where it fits
The Siemens 3RH1140-1BB40-ZW97 is a SIRIUS auxiliary contactor in the size S00 frame, carrying four normally-open instantaneous contacts. It's the part you grab when the control circuit needs to mirror a main contactor's state or add extra signal paths without pulling another power contactor into the panel. Coil is 24 V DC, pulling 3.2 W to close and the same 3.2 W to hold — no inrush spike to size your DC supply around. That's a straight number for the panel power budget. Rated operational current hits 10 A in AC-12 duty (resistive loads at line frequency), so it handles pilot-duty signalling, PLC outputs, and contactor coils within that envelope. At 230 V AC it's rated 6 A; at 400 V AC it drops to 3 A — the derating curve matters if you're switching a bank of contactor coils on a 400 V control transformer.
Mounting and panel integration
Mounts via screw or snap-on onto a DIN rail — the 45 mm width fits the standard S00 footprint, so it clips alongside a 3RT10 contactor without stealing extra rail space. The mounting position allows +/-180° rotation on a vertical surface and can be tilted forward/backward by +/-22.5°, which helps when the panel layout is tight and you need to orient the wiring entry. Front protection is IP20 — fine inside a closed cabinet, but keep it behind a panel door if there's any washdown or dust in the room. Pollution degree 3 means it's rated for conductive pollution environments typical of industrial control panels. Terminal capacity accepts solid conductors: 2x 0.5 to 1.5 mm², 2x 0.75 to 2.5 mm², or a single 4 mm². That covers most control wiring gauges you'll pull in a panel — no need for ferrule adapters on standard 1.5 mm² or 2.5 mm² runs.
Lifecycle and sourcing reality
Mechanical life is rated at 30 million operations typical, with contact reliability of one incorrect switching per 100 million operations at 17 V and 1 mA — that's the low-energy switching spec that matters when you're reading dry contacts from a PLC input card. Shock resistance is 10g for 5 ms and 5g for 10 ms, which covers most industrial vibration profiles without contact bounce. Surge voltage resistance is 6 kV, so it handles the transient spikes common in industrial control panels without flashover. Depth is 72 mm, height 57.5 mm — fits standard S00 enclosure cutouts.
Compliance and documentation
RoHS compliance date is 07/01/2006, so it meets the EU substance restrictions. The part carries the SIRIUS brand from Siemens, which means the usual CE, UL, CSA, and IEC certifications apply to the series — the specific approvals for this variant are listed on the nameplate and in the manufacturer's declaration. Operating temperature range is -25 to +60 °C; storage and transport range is -55 to +80 °C. That's a wide enough thermal envelope for unheated warehouses and shipping containers.