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Siemens 3RH2122-2LB40 PLC Output Contactor Relay - 24V DC

Siemens 3RH2122-2LB40 coupling contactor relay for PLC outputs.

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ManufacturerSiemens

Part number3RH2122-2LB40

Contacts 2 NO + 2 NC

Coil Voltage 24V DC

PLC Output Compatible Yes

Terminal Type Spring-loaded

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CAGE: 9NK75

2 NO + 2 NC auxiliary contacts 24V DC coil voltage Integrated varistor for surge suppression Spring-loaded terminal connections Frame size S00 Not expandable with aux switches

Product description

The Siemens 3RH2122-2LB40 is a coupling contactor relay designed for seamless integration with PLC outputs. It features 2 normally open (NO) and 2 normally closed (NC) auxiliary contacts, a 24V DC control voltage, and an integrated varistor for surge suppression. This relay utilizes spring-loaded terminals for secure connections and is housed in frame size S00. Similar to the -2KB40 variant, it is not expandable with auxiliary switches.

This model is ideal for applications requiring a reliable interface between low-power PLC outputs and higher-power control circuits. The integrated varistor offers enhanced protection against voltage transients, making it suitable for dynamic industrial environments such as manufacturing plants, automated assembly lines, and process control facilities.

Stanlo Automation, a veteran-owned surplus parts distributor, carries the Siemens 3RH2122-2LB40. We are committed to providing quality industrial components to our customers, ensuring operational continuity and cost-effectiveness. Trust Stanlo Automation for your surplus industrial automation needs.

Technical specifications

Contacts	2 NO + 2 NC
Coil Voltage	24V DC
PLC Output Compatible	Yes
Terminal Type	Spring-loaded
Frame Size	S00
Suppressor Device	Varistor
Expandable	No

Common applications

PLC interfacing

Automation control

Machine control

Industrial automation

Control panels

Compatible systems

Siemens S7 PLCs Other PLC systems with 24V DC outputs Industrial automation control systems

Also known as

Siemens 3RH2122-2LB40 PLC relay Siemens 24V DC coupling relay with varistor

Replaces / compatible with

Designed for direct connection to PLC outputs, offering surge protection via an integrated varistor.

Technical note

Expert tip

The integrated varistor provides effective suppression of voltage spikes, which is particularly beneficial in environments with electrical noise or unstable power.

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Frequently asked questions

What type of surge suppression is included in the Siemens 3RH2122-2LB40?

The Siemens 3RH2122-2LB40 features an integrated varistor, which is a component designed to protect the relay and connected circuitry from transient overvoltages.