Siemens SIRIUS coupling relay, 3RH2122-2KB40, 24 V DC, 2 NO contacts, size S00, with integrated suppressor diode, screw and snap-on 35 mm rail mount.
| 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 |
|---|---|
| Conductor cross-section, solid or stranded | 2x (0,5 ... 4 mm²) |
| Conductor cross-section, finely stranded w/ ferrule | 2x (0.5 ... 2.5 mm²) |
| Mounting method | screw and snap-on mounting onto 35 mm standard mounting rail |
| Parameter | Value |
|---|---|
| Durability (operating cycles, typ.) | 30 000 000 |
| 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 | 70 mm |
| Depth | 73 mm |
| Parameter | Value |
|---|---|
| At AC | 10 000 1/h |
The Siemens 3RH2122-2KB40 is a SIRIUS coupling relay sized S00, designed to switch auxiliary circuits — typically interposing between a 24 V DC PLC output and a contactor coil, or for signal isolation.
The built-in suppressor diode means you don't add an external flyback diode across this relay when driving it from a transistor output. One less component, one less joint to check.
No, the 3RH2122-2KB40 is a coupling relay for auxiliary circuits, while the 3RT2028-1BB40 is a contactor for main motor loads. They serve different functions and are not electrical or mechanical substitutes.
The relay is RoHS compliant per substance prohibitance dated 10/01/2009, and rated for pollution degree 3 environments. No specific UL or CSA marking is listed in the specifications.
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