The Siemens SIRIUS 3RH1140-2KB40 is a coupling relay for switching auxiliary circuits, carrying 4 instantaneous NO contacts rated at 10 A at 24 V (AC-12 maximum). The coil pulls in at 24 VDC, consuming 2.3 W for both closing and holding — a steady-state draw that simplifies power-supply budgeting in a 24 VDC control loop. No auxiliary switch or delayed/make-before-break switching is built in; this is a straight four-pole normally-open relay for signal-level or low-power load isolation.
Mounting and panel fit
Mounts via screw or snap-on onto a DIN rail, with the size S00 footprint (45 mm wide, 60 mm tall, 73 mm deep). The mounting position allows ±180° rotation on a vertical surface and ±22.5° forward/backward tilt — useful when fitting into a crowded panel where orientation flexibility avoids re-routing wire bundles.
Environmental and isolation
Rated for pollution degree 3, surge voltage resistance of 6 kV, and IP20 finger-safe protection on the front. Operating temperature spans -25 to +60 °C; storage and transport extend to -55 to +80 °C. Shock resistance is specified at 10g / 5 ms and 5g / 10 ms — adequate for panel-mounted equipment in industrial machinery subject to intermittent vibration.
Wiring and suppression
Terminals accept solid conductors from 0.25 to 2.5 mm² (2x per clamp) and finely stranded with ferrule from 0.25 to 1.5 mm². A built-in varistor provides surge suppression across the coil — no external snubber needed for standard 24 VDC switching, though verify polarity if the circuit includes free-wheeling diodes elsewhere.