Siemens SIRIUS 3RQ3 Slim Coupling Relays

Siemens SIRIUS 3RQ3 Slim Coupling Relays Suppliers,Exporters in India

ARP IMPEX is a supplier and exporter of Siemens SIRIUS 3RQ3 Slim Coupling Relays in India. We handle requirements for PLC control panels, machine automation, process plants, signal isolation, voltage conversion and replacement of existing Siemens 3RQ3 relay couplers.

The Siemens 3RQ3 is a narrow coupling relay used between a controller and field equipment. It transfers input and output signals while keeping the controller circuit electrically separated from the connected contactor, valve, alarm, sensor or other field device.

With a width of only 6.2 mm, the relay takes up very little DIN-rail space. This makes it useful in compact control panels where a large number of PLC interface relays must be installed next to each other.

The 3RQ3 range includes versions with a permanently fitted electromechanical relay, replaceable plug-in relay and semiconductor output. Siemens also supplied models with manual and automatic selector switches for commissioning, maintenance and local testing.

Different input voltages, contact arrangements, output types and terminal systems are available under the 3RQ3 family. Buyers should therefore share the complete Siemens part number rather than requesting only a “3RQ3 coupling relay.”

Siemens has announced the discontinuation of the SIRIUS 3RQ3 range from October 1, 2026. The new SIRIUS 3RQ4 coupling relay series is its successor. ARP IMPEX handles enquiries for existing 3RQ3 part numbers as well as suitable 3RQ4 replacement models, subject to technical verification.

For Siemens SIRIUS 3RQ3 price and availability, send the complete part number, required quantity and destination country.

Siemens 3RQ3 Product Versions

3RQ3 Coupling Relays with Fixed Relay Output

These models have an electromechanical relay permanently installed inside the coupling module.

The fixed construction reduces the number of removable parts and provides dependable contact operation for normal industrial control applications. It is suitable where frequent relay replacement is not expected.

Applicable versions are available with standard or hard gold-plated contacts. Gold-plated contacts are generally selected for low-current electronic and PLC signals where ordinary contacts may not switch reliably.

Typical uses include:

• PLC output isolation
• Contactor-coil switching
• Solenoid-valve control
• Alarm and indication circuits
• Signal amplification
• Control-voltage conversion
• General industrial relay control

3RQ3 Coupling Relays with Plug-In Relay

These versions use a replaceable elementary relay fitted into the coupling module.

If the relay reaches the end of its service life, the plug-in component can be replaced without removing the complete terminal base or disturbing the permanent panel wiring.

This type is useful for machines and production lines where maintenance teams prefer to replace the switching relay during servicing rather than rewire the complete interface module.

Plug-in models are also available with hard gold-plated contacts for applicable low-current control signals.

3RQ3 Coupling Relays with Semiconductor Output

Semiconductor versions switch the connected DC load electronically instead of using mechanical contacts.

They are useful where the application requires:

• Frequent switching
• Fast response
• Silent operation
• Long electrical service life
• No mechanical contact wear
• Reliable switching of repetitive control signals

Applicable semiconductor models were supplied for input and output coupling duties. Some versions also include short-circuit-resistant outputs.

The switched voltage, output current and polarity must match the complete Siemens part number. A semiconductor relay cannot automatically replace an electromechanical changeover-contact relay.

3RQ3 Relays with Manual and Automatic Selector Switch

Selected versions include a manual/automatic selector switch.

In automatic mode, the output follows the controller signal. Manual mode allows the technician to operate the output locally during commissioning, testing or maintenance.

This function can be useful for checking valves, contactors, indicators and other field devices without repeatedly changing the PLC program.

Manual operation should only be used according to the approved machine procedure. It must not bypass safety interlocks or create an unsafe operating condition.

Technical Specifications

The Siemens 3RQ3 is a product family, so the final specifications depend on the full article number.

• Brand: Siemens
• Product range: SIRIUS
• Series: 3RQ3
• Product type: Slim coupling and interface relay
• Main purpose: Signal isolation, amplification and voltage conversion
• Mounting width: 6.2 mm
• Mounting: Standard DIN rail
• Relay versions: Permanently fitted relay or replaceable plug-in relay
• Electronic versions: Semiconductor-output coupling relays
• Contact arrangements: One or two changeover contacts on applicable versions
• Contact material: Standard or hard gold-plated contacts
• Control voltage: Depends on the complete article number
• Output rating: Depends on relay or semiconductor version
• Terminal options: Screw or push-in spring terminals
• Potential distribution: Plug-in comb jumpers available
• Selector switch: Manual/automatic versions available
• Application: Input and output coupling
• Controller interface: Suitable for PLC and industrial automation signals
• Approvals: Depend on the selected Siemens article number
• Successor series: Siemens SIRIUS 3RQ4

The input voltage, number of contacts, contact material, output type, and terminal system must be confirmed from the complete Siemens part number before issuing a quotation.

Features

• Slim 6.2 mm design saves control-panel space
• Suitable for PLC input and output interfacing
• Provides galvanic isolation between controller and field circuits
• Converts signals between different control-voltage levels
• Amplifies controller signals for switching field equipment
• Fixed relay-output versions provide dependable contact operation
• Plug-in relay versions allow faster replacement during maintenance
• Semiconductor versions suit frequent and silent switching
• Hard gold-plated contacts are available for low-current signals
• Manual/automatic selector-switch versions support commissioning
• Screw and push-in terminal options are available
• Push-in terminals allow tool-free wiring with suitable conductors
• Comb jumpers simplify common-potential distribution
• Reduces individual wiring across groups of interface relays
• Suitable for narrow tier spacing and shallow control boxes
• Protects controller interfaces from field-side voltage peaks
• Helps reduce electromagnetic interference reaching the PLC
• Can switch contactors, valves, indicators and control signals
• Useful for new control panels and existing 3RQ3 replacement
• Suitable 3RQ4 successor models are available for phased-out requirements

Control-Panel Wiring Advantages

When several coupling relays use the same supply potential, wiring each relay individually can take time and create unnecessary cable loops.

The 3RQ3 range supports comb-type jumpers for distributing a common potential across several adjacent devices. This reduces individual jumper wiring and keeps the panel layout cleaner.

Both screw and push-in terminal versions were supplied. Push-in terminals allow a prepared solid or ferruled conductor to be inserted directly without tightening a screw.

The narrow design also allows panel builders to install more coupling points within the same DIN-rail length. This can be valuable in PLC panels with hundreds of digital inputs and outputs.

Applications

Siemens SIRIUS 3RQ3 Coupling Relays are used for:

• PLC input isolation
• PLC output isolation
• Signal amplification
• Control-voltage conversion
• Contactor-coil switching
• Solenoid-valve control
• Alarm and indication circuits
• Motor control panels
• Machine automation systems
• Process-control panels
• Packaging machinery
• Conveyor control systems
• Material-handling equipment
• Pump and compressor panels
• HVAC control systems
• Building automation
• Water and wastewater treatment plants
• Chemical and process industries
• Food and beverage machinery
• Pharmaceutical production equipment
• Automotive manufacturing lines
• Industrial ovens and furnaces
• Remote-control systems
• Railway control panels
• Marine and infrastructure projects
• Flat switchboxes
• Control cabinets with limited DIN-rail space
• Replacement of existing Siemens 3RQ3 relays
• Migration from Siemens 3RQ3 to 3RQ4

The 3RQ3 is particularly useful where many PLC signals must be isolated or converted within a limited panel area. It allows panel builders to fit a large number of interface points without using wider industrial coupling relays.

Siemens 3RQ3 and 3RQ2 Difference

Both ranges provide signal isolation, amplification and voltage conversion, but their physical designs and product options differ.

• Siemens 3RQ2: Universal coupling relay in a wider industrial housing with up to three changeover contacts and a wide-range supply
• Siemens 3RQ3: Slim 6.2 mm coupling relay with fixed, plug-in or semiconductor output versions

The 3RQ2 may be more appropriate where the panel requires several changeover contacts or a universal 24–240 V AC/DC control supply.

The 3RQ3 is generally selected where DIN-rail space is limited or where fixed relay, replaceable relay and semiconductor-output options are required within the same slim product family.

Siemens 3RQ3 and 3RQ1 Difference

The 3RQ3 is mainly intended for normal industrial PLC and automation signals.

The Siemens 3RQ1 uses force-guided contacts and is intended for monitored and safety-related control circuits.

A standard 3RQ3 relay should not replace a force-guided 3RQ1 in an emergency-stop, safety-door or other certified safety circuit only because the voltage and contact quantity appear similar.

Siemens 3RQ3 Replacement with 3RQ4

Siemens has introduced the SIRIUS 3RQ4 as the successor to the 3RQ3 range.

The 3RQ4 family includes:

• Coupling relays with an integrated relay output
• Coupling relays with a replaceable plug-in relay
• Coupling relays with semiconductor output

A 3RQ4 replacement should be selected by comparing the complete functions of the installed 3RQ3.

The following points must be checked:

• Existing Siemens 3RQ3 article number
• Input or output coupling application
• Control voltage
• Electromechanical or semiconductor output
• Number and type of contacts
• Standard or hard gold-plated contacts
• Switched voltage and current
• Screw or push-in terminals
• Manual/automatic selector-switch requirement
• Comb-jumper arrangement
• Available panel dimensions
• Required industrial or railway approvals

The new series may have changes in terminal arrangement, dimensions, output rating or available accessories. A 3RQ4 should not be described as a direct replacement until the old and new article numbers have been compared.

Selecting the Correct Siemens 3RQ3 Relay

A request for “Siemens 3RQ3 Relay” does not identify the complete product.

For an accurate quotation, share:

• Complete Siemens article number
• Required quantity
• Destination country
• Input or output coupling requirement
• Control voltage
• Relay or semiconductor output
• Required contact arrangement
• Screw or push-in terminal type
• Manual/automatic selector-switch requirement

For a replacement requirement, also send a clear photograph of the existing relay label and terminal arrangement.

If the old 3RQ3 part number is unavailable, confirm whether the relay switches a contactor, solenoid valve, PLC input, indicator, alarm or another field device.

Siemens SIRIUS 3RQ3 Supplier and Exporter in India

ARP IMPEX supplies Siemens SIRIUS 3RQ3 Slim Coupling Relays for panel builders, machine manufacturers, system integrators, industrial plants, infrastructure contractors, maintenance companies and export buyers.

We handle enquiries for Siemens 3RQ3 fixed relay couplers, plug-in coupling relays, semiconductor interface relays, PLC input and output couplers, relays with manual/automatic switches and suitable Siemens 3RQ4 replacement models.

The Siemens 3RQ3 price depends on the complete part number, supply voltage, output type, contact arrangement, terminal system and ordered quantity.

Send the complete Siemens part number, required quantity and destination country for price, availability and export quotation.