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Siemens 3RH2122-4LB40-0LA0 SIRIUS Auxiliary Contactor

MPN3RH2122-4LB40-0LA0

Siemens SIRIUS 3RH2122-4LB40-0LA0 auxiliary contactor, size S00, 24 VDC coil, 2 NO instantaneous contacts, 45 mm width, 117 mm depth, 57.5 mm height, screw and snap-on mounting on 35 mm DIN rail.

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Siemens 3RH2122-4LB40-0LA0 datasheet (PDF)

Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

3RH2122-4LB40-0LA0 — Identification
Parameter	Value
Contactor frame size	S00

3RH2122-4LB40-0LA0 — Ratings & Performance
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

3RH2122-4LB40-0LA0 — Control & Coil
Parameter	Value
Control supply voltage type	DC

3RH2122-4LB40-0LA0 — Contacts & Poles
Parameter	Value
Auxiliary contact reliability	1 faulty switching per 100 million (17 V, 1 mA)

3RH2122-4LB40-0LA0 — Connection & Mounting
Parameter	Value
Mounting method	screw and snap-on mounting onto 35 mm DIN rail

3RH2122-4LB40-0LA0 — Durability
Parameter	Value
Durability (operating cycles, typ.)	30 000 000
Durability with aux. switch block (cycles, typ.)	10 000 000

3RH2122-4LB40-0LA0 — Environmental
Parameter	Value
Operating temperature range	-40 ... +70 °C
Storage temperature range	-55 ... +80 °C
Installation altitude, max.	2 000 m

3RH2122-4LB40-0LA0 — Mechanical
Parameter	Value
Width	45 mm
Height	57.5 mm
Depth	117 mm

3RH2122-4LB40-0LA0 — Specifications
Parameter	Value
At AC	10 000 1/h

Product details

Panel fit and switching duty for the SIRIUS S00

The 3RH2122-4LB40-0LA0: This is a Siemens SIRIUS auxiliary contactor in the S00 frame size, designed for switching signal and control circuits rather than motor loads directly. The 24 VDC coil draws 13 W on closing and 4 W holding, which keeps the thermal load low inside a crowded panel.

DIN rail mounting and envelope constraints

The 45 mm width and 117 mm depth fit standard S00 contactor spacing; the 57.5 mm height leaves clearance under typical distribution board covers.

Switching performance and environmental ratings

The integrated varistor surge suppressor clips coil transients at turn-off, extending contact life in inductive circuits. Mechanical endurance is 30 million cycles typical.

Frequently asked questions

What is the 3RH2122-4LB40-0LA0 used for?

It is an auxiliary contactor used to switch control and signal circuits in industrial panels — typically interlocking, status feedback, or pilot-duty loads. The 2 NO contacts handle both 24 VDC and 230 VAC circuits at 10 A.