What it is
The 3RH2140-2FB40 is a SIRIUS auxiliary contactor from Siemens, size S00. It carries 4 normally open instantaneous contacts and a 24 V DC coil. The diode surge suppressor is built in — no external flyback diode needed when switching DC loads.
Key ratings and what they mean
Mechanical life is rated at 30 million operations, so it holds up in high-cycle applications like conveyor interlock chains or machine safety circuits. The coil closing power is 4 W DC, keeps the control transformer loading predictable. Operating temperature range is -25 to +60 °C, storage from -55 to +80 °C. Mounting position is flexible: ±180° rotation on a vertical surface, plus ±22.5° tilt forward/backward. The DIN rail clip is tool-free.
Mounting and connections
Mounts on 35 mm DIN rail with screw and snap-on fastening. Clearance margins: 10 mm upwards, 10 mm downwards, 6 mm sideways, 10 mm forwards. Conductor cross-section 2 x (0.5...4 mm²) solid or stranded — suitable for standard control wiring.