The Siemens SIRIUS 3RH2140-4KB40 is a coupling relay designed for switching auxiliary circuits in control panels. It carries 4 instantaneous normally-open contacts and is driven by a 24 VDC coil with a built-in suppressor diode. The S00 size keeps the footprint tight — 45 mm wide, 57.5 mm tall, 73 mm deep — so it fits easily into crowded DIN-rail enclosures. Rated switching current at 24 V is 10 A, with derated curves for higher voltages: 4.7 A at 60 V, 3 A at 110 V, 1.2 A at 220 V, and so on up to 0.26 A at 600 V.
Siemens 3RH2140-4KB40 SIRIUS Coupling Relay, 24 VDC, 4 NO Co
MPN3RH2140-4KB40
Siemens SIRIUS coupling relay, 3RH2140-4KB40, 24 VDC coil, 4 NO instantaneous contacts, S00 size, screw and snap-on 35 mm DIN rail mounting.
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026
Specifications
| Parameter | Value |
|---|---|
| Contactor frame size | S00 |
| Parameter | Value |
|---|---|
| Rated operational current, AC-12, max. | 10 A |
| Rated value @ 400 V | 3 A |
| Rated value @ 500 V | 2 A |
| Rated value @ 690 V | 1 A |
| Rated value @ 230 V | 10 A |
| Rated value @ 24 V | 10 A |
| Rated value @ 60 V | 4.7 A |
| Rated value @ 110 V | 3 A |
| Rated value @ 220 V | 1.2 A |
| Parameter | Value |
|---|---|
| Control supply voltage type | DC |
| Parameter | Value |
|---|---|
| Auxiliary contact reliability | 1 faulty switching per 100 million (17 V, 1 mA) |
| Parameter | Value |
|---|---|
| Mounting method | screw and snap-on mounting onto 35 mm DIN rail |
| Parameter | Value |
|---|---|
| Durability (operating cycles, typ.) | 30 000 000 |
| Durability with aux. switch block (cycles, typ.) | 10 000 000 |
| Parameter | Value |
|---|---|
| Operating temperature range | -25 ... +60 °C |
| Storage temperature range | -55 ... +80 °C |
| Installation altitude, max. | 2 000 m |
| Parameter | Value |
|---|---|
| Width | 45 mm |
| Height | 57.5 mm |
| Depth | 73 mm |
| Parameter | Value |
|---|---|
| At AC | 10 000 1/h |
Product details
Frequently asked questions
What is the closest functional second-source for 3RH2140-4KB40?
Within the same SIRIUS family, the 3RH2140-1BP40 shares the S00 size and 4-contact layout but uses a different coil voltage or termination. Check the coil rating before substituting — the -4KB40 is 24 VDC with a built-in suppressor diode. The -1BP40 may not have the same coil suppression, so verify free-wheel diode polarity if swapping.
Will 3RH2140-4KB40 drop into a panel specified around 3RH2140-1BP40 without rewiring?
Mechanically yes — same S00 size, same DIN rail footprint, same screw/snap-on mounting. Electrically only if the coil voltage matches. The -4KB40 runs on 24 VDC; if the -1BP40 was also 24 VDC, the swap is direct. If not, the coil circuit needs re-termination.
What compliance documentation does this brand provide for 3RH2140-4KB40?
The part carries a RoHS substance prohibition date of 10/01/2009, indicating compliance with the RoHS directive. Standard Siemens SIRIUS documentation includes CE declaration of conformity and, where applicable, UL/CSA certification. Request specific certificates at RFQ time.
Where can I buy 3RH2140-4KB40 and how is it quoted?
This part is sourced to order through independent industrial-automation distribution. Submit an RFQ for the 3RH2140-4KB40 line item; availability and current pricing are confirmed at quote time. No minimum order quantity is imposed for standard quantities.
MPN
3RH2140-4KB40