The 3RH2140-1BN40 is a SIRIUS auxiliary contactor from Siemens, size S00, with 4 normally-open instantaneous contacts. It's built to switch control signals and auxiliary loads in motor starter and contactor assemblies, not to carry main motor current itself. The four NO contacts are rated for DC switching across a range of voltages: 10 A at 24 V, 4.7 A at 60 V, 3 A at 110 V, 1.2 A at 220 V, and 0.26 A at 600 V. That means it handles DC control circuits common in 24 VDC panels, and can also manage higher-voltage DC loads like valve solenoids or brake coils where the voltage is stepped up. The magnet coil draws 4 W on closing and 4 W to hold — a constant-power coil that doesn't spike on pickup, so it's gentle on the PLC output or relay driving it.
The S00 frame size keeps the footprint tight: 57.5 mm high, 45 mm wide, 73 mm deep. Wiring terminals accept two conductors per clamp: 2x 0.5–1.5 mm² solid or stranded, 2x 0.75–2.5 mm², or 2x 4 mm² — enough for daisy-chaining control wiring without extra terminal blocks.