The Siemens SIRIUS 3RH2140-1WB40 is a coupling relay for switching auxiliary circuits, built into the S00 contactor footprint. It carries 4 normally-open instantaneous contacts and a 24 VDC coil with integrated varistor surge suppression. Rated 10 A at 24 V (AC-12 / AC-15 duty), it handles the auxiliary load of contactors, relays, and PLC outputs in control panels. The 45 mm width and 73 mm depth fit the standard S00 slot on a 35 mm DIN rail; screw and snap-on mounting means it clips in alongside the main contactor without extra hardware.
Mounting and integration
Mounts via screw and snap-on onto 35 mm DIN rail. The S00 size (45 mm wide) matches the footprint of Siemens 3RT2 contactors in the same frame — it clips directly to the left or right of the contactor using the integrated snap-on feature. Clearance: 10 mm upwards, 10 mm forwards, 10 mm downwards, 6 mm at the side. The mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward, so panel layout is flexible.
Contact ratings and switching capability
The 4 NO contacts are rated for AC switching at multiple voltages: 10 A at 24 V, 4.7 A at 60 V, 3 A at 110 V, 1.2 A at 220 V, 10 A at 230 V, 3 A at 400 V, 0.5 A at 440 V, 2 A at 500 V, 0.26 A at 600 V, and 1 A at 690 V. Mechanical life is 30 million operations typical; electrical life depends on load but the AC switching rate is rated at 10 000 operations per hour. Arcing time runs 10 to 15 ms. The varistor surge suppressor across the coil absorbs back-EMF, which matters when the relay is driven by a PLC output — no external flyback diode needed.
Wire termination accepts solid or stranded conductors: 2× (0.5 to 1.5 mm²), 2× (0.75 to 2.5 mm²), or 2× 4 mm². The product extension auxiliary switch is not included (no add-on block). Relative humidity minimum 10%.