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Siemens 3RH2122-1KB40 — Contactors

Siemens 3RH2122-1KB40 SIRIUS Coupling Relay, 24 VDC, 2 NO

MPN3RH2122-1KB40
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Siemens SIRIUS 3RH2122-1KB40, coupling relay for switching auxiliary circuits, 24 V DC coil, 2 N/O contacts, size S00, screw and snap-on DIN rail mounting.

$24.13Ref. price · indicative, final on quote
Siemens 3RH2122-1KB40 datasheet (PDF)
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

3RH2122-1KB40 — Identification
ParameterValue
Contactor frame sizeS00
3RH2122-1KB40 — Ratings & Performance
ParameterValue
Rated operational current, AC-12, max.10 A
Rated value @ 400 V3 A
Rated value @ 500 V2 A
Rated value @ 690 V1 A
Rated value @ 230 V10 A
Rated value @ 24 V10 A
Rated value @ 60 V4.7 A
Rated value @ 110 V3 A
Rated value @ 220 V1.2 A
3RH2122-1KB40 — Control & Coil
ParameterValue
Control supply voltage typeDC
3RH2122-1KB40 — Contacts & Poles
ParameterValue
Auxiliary contact reliability1 faulty switching per 100 million (17 V, 1 mA)
3RH2122-1KB40 — Connection & Mounting
ParameterValue
Conductor cross-section, solid or stranded2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²), 2x 4 mm²
Conductor cross-section, finely stranded w/ ferrule2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)
Mounting methodscrew and snap-on mounting onto 35 mm DIN rail
3RH2122-1KB40 — Durability
ParameterValue
Durability (operating cycles, typ.)30 000 000
3RH2122-1KB40 — Environmental
ParameterValue
Operating temperature range-25 ... +60 °C
Storage temperature range-55 ... +80 °C
Installation altitude, max.2 000 m
3RH2122-1KB40 — Mechanical
ParameterValue
Width45 mm
Height57.5 mm
Depth73 mm
3RH2122-1KB40 — Specifications
ParameterValue
At AC10 000 1/h

Product details

The Siemens 3RH2122-1KB40 is a SIRIUS coupling relay for auxiliary circuit switching: 24 V DC coil with integrated suppressor diode, 2 normally-open instantaneous contacts, and a rated mechanical life of 30 million cycles.

Coil & Contact Ratings

Coil draws 2.8 W at 24 V DC. The rated operational current per voltage is 10 A, 10 A, 3 A, and 1 A.

Fastening via screw clamp or snap-on to 35 mm DIN rail. Required clearances for proper arcing and cooling: 10 mm upward and forward, 10 mm downward, 6 mm to the side.

Frequently asked questions

What are the key dimensions of the 3RH2122-1KB40?

Depth is 73 mm, width is 45 mm, height is 57.5 mm. It fits the S00 contactor frame size and mounts on 35 mm DIN rail.

Does the 3RH2122-1KB40 include a surge suppressor?

Yes, the design incorporates a suppressor diode across the coil, eliminating the need for an external flyback diode on DC circuits.

MPN
3RH2122-1KB40