Product Description

Siemens 3RH2911-1HA31 Auxiliary Contact Block – 3 NO + 1 NC

The Siemens 3RH2911-1HA31 is a front-mountable auxiliary contact block from the Siemens SIRIUS range, designed for compatible 3RT2 contactors and 3RH2 contactor relays. It provides 3 normally open (NO) and 1 normally closed (NC) instantaneous auxiliary contacts with screw-terminal connections. Siemens identifies this exact article as an active product for front snapping onto compatible devices.

The auxiliary contact block is used to expand the control, signalling, feedback and interlocking capability of a compatible contactor without changing its main power-switching function.

Siemens SIRIUS Auxiliary Contact Block

The 3RH2911-1HA31 provides additional auxiliary contacts for industrial control and automation circuits.

These contacts can be used for:

• Contactor status feedback

• PLC input signals

• Electrical interlocking

• Control-circuit logic

• Machine sequencing

• Auxiliary signalling

• Motor-control circuits

• Industrial automation

Siemens specifies this auxiliary switch for compatible 3RT2.1, 3RT2.2, 3RT2.3, 3RT2.4 and 3RH2 devices.

3 NO + 1 NC Auxiliary Contacts

The 3RH2911-1HA31 provides a total of 4 instantaneous auxiliary contacts:

3 NO + 1 NC

The contact arrangement consists of:

• 1 NC contact

• 3 NO contacts

This combination provides flexibility for simultaneous feedback, signalling and interlocking functions. Siemens identifies the current paths as .1/.2 for the NC path and .3/.4 for the three NO paths.

Typical uses include:

• Contactor ON feedback

• PLC monitoring

• Electrical interlocking

• Machine sequencing

• Auxiliary signalling

• Status indication

• Control-system logic

Front-Snap Mounting

The 3RH2911-1HA31 is designed to snap onto the front of compatible SIRIUS contactors and contactor relays.

This front-mounted configuration allows additional auxiliary contacts to be added directly to the contactor while maintaining a compact control-panel arrangement. Siemens describes it specifically as an auxiliary switch for snapping onto the front.

It is suitable for:

• Motor starters

• Machine-control panels

• Automation cabinets

• OEM control systems

• Industrial electrical assemblies

Screw-Terminal Connections

The 3RH2911-1HA31 uses screw terminals for its auxiliary-contact connections.

This provides a conventional connection method for electrical panel builders and maintenance teams and supports practical wiring of control and signalling circuits.

Instantaneous Auxiliary Contacts

All four contacts in this configuration are instantaneous. Siemens specifies 3 instantaneous NO contacts and 1 instantaneous NC contact.

This makes the accessory suitable for applications where auxiliary switching must follow the operating state of the connected contactor or contactor relay without a separate timing delay.

Compatibility with SIRIUS Contactors

The 3RH2911-1HA31 is designed for compatible Siemens SIRIUS devices, including:

• 3RT2.1 contactors

• 3RT2.2 contactors

• 3RT2.3 contactors

• 3RT2.4 contactors

• 3RH2 contactor relays

Compatibility should be checked against the exact device article number before installation.

Industrial Automation Applications

The 3RH2911-1HA31 can expand the control functionality of compatible contactors and contactor relays.

Motor Control

The auxiliary contacts can provide contactor-state feedback and interlocking signals within motor starters.

PLC Systems

The contacts can be connected to PLC digital inputs for monitoring and sequence control.

Machine Control

The 3 NO + 1 NC arrangement can support control logic, interlocking and machine sequencing.

Industrial Control Panels

The front-snap design makes it easy to add auxiliary switching capability directly to compatible contactors.

Automation Systems

The additional contacts provide multiple control and signalling paths within automated machinery.

Suitable for OEMs and Panel Builders

The 3RH2911-1HA31 is suitable for OEM machine manufacturers, electrical panel builders, automation integrators and industrial maintenance professionals.

Its combination of 3 NO + 1 NC instantaneous contacts, front mounting and screw terminals makes it a practical accessory for expanding compatible Siemens SIRIUS contactor assemblies.

Key Features

• Siemens SIRIUS auxiliary contact block

• Article number 3RH2911-1HA31

• Front-mountable design

• Snap-on mounting

• 3 NO + 1 NC auxiliary contacts

• All contacts instantaneous

• Screw terminals

• Compatible with selected 3RT2 contactors

• Compatible with 3RH2 contactor relays

• Suitable for PLC feedback

• Suitable for electrical interlocking

• Suitable for signalling and control

• Suitable for industrial automation

Benefits

• 3 NO + 1 NC contacts: Provides four additional auxiliary switching paths.

• Front mounting: Allows convenient installation directly onto compatible devices.

• Screw terminals: Provides a familiar wiring method for industrial control panels.

• PLC integration: Supports contactor-state monitoring.

• Interlocking support: The NC contact can be used in suitable interlocking circuits.

• Flexible control logic: The combination of NO and NC contacts supports multiple control functions.

• Compact design: Helps maintain an organized control-panel layout.

• Easy expansion: Adds auxiliary functionality without replacing the main contactor.

Why Choose Siemens 3RH2911-1HA31?

The Siemens 3RH2911-1HA31 provides a practical solution for applications requiring additional contactor control, feedback, interlocking and signalling.

Its 3 NO + 1 NC instantaneous contact arrangement, front-snap mounting and screw-terminal connections make it suitable for industrial motor-control panels, automation systems and OEM machinery.

Siemens currently lists the 3RH2911-1HA31 as an active product, and its official product data confirms compatibility with the relevant 3RT2 and 3RH2 device families.

Delivery Across India

SB Smart supplies Siemens industrial electrical and automation products across Faridabad, Gurgaon/Gurugram, Delhi NCR, Haryana, Noida, Punjab, Mumbai and all major cities across India.

Major delivery locations include:

• Faridabad

• Gurgaon/Gurugram

• Delhi

• Delhi NCR

• Noida

• Greater Noida

• Haryana

• Punjab

• Mumbai

• Pune

• Ahmedabad

• Bengaluru

• Hyderabad

• Chennai

• Kolkata

• Jaipur

• Chandigarh

• Lucknow

• Indore

• Surat

• Vadodara

• Nagpur

• Coimbatore

• And other major cities across India

Frequently Asked Questions

1. What is Siemens 3RH2911-1HA31?

It is a Siemens SIRIUS front-mountable auxiliary contact block for compatible 3RT2 contactors and 3RH2 contactor relays.

2. How many auxiliary contacts does it provide?

It provides 3 normally open and 1 normally closed contacts.

3. Are the contacts instantaneous?

Yes. The configuration includes 3 instantaneous NO and 1 instantaneous NC contacts.

4. How is it mounted?

It is designed for snap-on mounting directly onto the front of compatible SIRIUS devices.

5. What type of terminals does it use?

It uses screw terminals.

6. Which Siemens devices are compatible?

It is specified for compatible 3RT2.1, 3RT2.2, 3RT2.3, 3RT2.4 and 3RH2 devices.

7. What can the auxiliary contacts be used for?

They can be used for PLC feedback, signalling, interlocking, control logic and machine sequencing.

8. Does it switch the main electrical load?

No. It provides auxiliary contacts for control and signalling; the main load remains switched by the compatible contactor.

9. Is it suitable for OEM machinery?

Yes. It is suitable for OEM machine builders, panel manufacturers, automation integrators and industrial maintenance applications.

10. Where can I buy Siemens 3RH2911-1HA31 in India?

You can explore the Siemens product range at SB Smart for Siemens auxiliary contact blocks, contactors, contactor relays and other industrial automation products.