What this part is and where it fits
The Siemens SIRIUS 3RH2140-1HB40 is a coupling relay — a contactor-style device built to switch auxiliary circuits in control panels. It carries 4 normally-open instantaneous contacts, each rated 10 A at 24 V, and snaps onto a 35 mm DIN rail alongside the main contactor it follows. The size S00 footprint (45 mm wide, 73 mm deep, 57.5 mm high) keeps it compact for dense panel layouts. The 24 VDC coil draws 2.8 W on both closing and holding — no power penalty for keeping it energized. Operating temperature spans -25 to +60 °C, with storage from -55 to +80 °C, so it handles unheated enclosures in temperate climates without derating.
Mounting and clearances
Mounts via screw or snap-on onto 35 mm DIN rail. The mounting position is flexible: ±180° rotation on a vertical surface, plus ±22.5° tilt forward or backward. Minimum clearances around the relay: 10 mm upward, 10 mm forward, 10 mm downward, 6 mm at the sides — tight enough for high-density rows. Terminals accept solid or stranded wire: 2× (0.5 to 1.5 mm²), 2× (0.75 to 2.5 mm²), or 2× 4 mm². Pollution degree 3 rating means it's suited for industrial environments with conductive dust or occasional condensation.
Switching capacity across voltages
The 4 NO contacts are rated for switching across a wide voltage range. At 24 V the rated current is 10 A; at 230 V it's also 10 A. Higher voltages see derating: 3 A at 110 V, 1.2 A at 220 V, 3 A at 400 V, 2 A at 500 V, 1 A at 690 V, and 0.26 A at 600 V. The DC ratings at 60 V and 440 V are 4.7 A and 0.5 A respectively — useful for mixed AC/DC control circuits.