The Siemens 3RH2140-1BB40-ZX95 is a SIRIUS auxiliary contactor in frame size S00 — a compact 45 mm wide, 57.5 mm tall, 73 mm deep block that screws or snaps onto 35 mm DIN rail. It carries four normally-open instantaneous contacts, coil rated 24 VDC with a closing and holding power draw of 4 W. This is the part you reach for when a contactor or starter needs extra signal contacts, or when you're building a dedicated interlock chain in a control panel.
Contact ratings — what the numbers mean
At higher DC voltages the current drops sharply — 4.7 A at 60 V, 1.2 A at 220 V, 0.26 A at 600 V — because DC arcs are harder to extinguish. Arcing time runs 10 to 15 ms. That's the spec-sheet story; the real-world takeaway is that this is a signal-duty block, not a power-switching device — use it for control circuits, PLC inputs, auxiliary relays, and contactor coils, not for motor loads directly.
Wire termination accepts 2x 0.5 to 1.5 mm² solid/stranded, 2x 0.75 to 2.5 mm², or 2x 4 mm².