Siemens SIRIUS 3RR2 Current Monitoring Relays

Siemens SIRIUS 3RR2 Current Monitoring Relays Suppliers,Exporters in India

ARP IMPEX is a supplier and exporter of Siemens SIRIUS 3RR2 Current Monitoring Relays in India. We handle requirements for motor feeders, pumps, conveyors, compressors, cranes, industrial machines, process equipment and existing Siemens control-panel replacements.

The Siemens 3RR2 monitors the current drawn by a motor or another three-phase electrical load. A change in current can indicate that something has changed in the machine or process, even when the motor is still running.

For example, a pump may draw less current when it runs dry, a conveyor may draw more current when the belt is overloaded, and a machine may show uneven phase currents when a cable or supply phase develops a problem. The 3RR2 can identify these conditions and operate an alarm or switching contact before the fault causes a longer shutdown.

The relay mounts directly onto a compatible Siemens SIRIUS 3RT2 contactor. The load current passes through the relay without requiring separate current transformers or additional main-circuit wiring. This makes it useful for compact motor starters where current monitoring must be added without using a separate measuring unit.

The 3RR2 range includes basic analogue models, digital versions with additional monitoring functions and 3RR24 models with IO-Link communication. The correct relay depends on the contactor size, motor current, type of current being monitored, control voltage and required outputs.

For Siemens SIRIUS 3RR2 Current Monitoring Relay price and availability, send the complete Siemens part number, required quantity and destination country.

What are the Siemens 3RR2 Monitors?

The 3RR2 can monitor whether the operating current rises above or falls below an adjustable limit.

An overcurrent condition may indicate:

• Excessive mechanical loading
• A blocked conveyor
• A jammed machine
• Increased bearing resistance
• A pump or compressor operating against excessive pressure
• A heater or other electrical load drawing too much current
• An undercurrent condition may indicate:
• Pump dry running
• Loss of mechanical load
• A torn or slipping drive belt
• A broken coupling
• No material on a conveyor
• A heating element or load circuit that is no longer operating
• Open-circuit or phase-related problems

Digital models can also monitor phase failure, phase sequence, current asymmetry and other load conditions, depending on the selected article number. Siemens positions the 3RR2 for monitoring both the electrical load and the behaviour of the driven process.

Siemens 3RR2 Product Versions

Siemens 3RR21 Basic Current Monitoring Relays

The Siemens 3RR21 range provides a straightforward option for monitoring apparent current.

These models use analogue front adjustment and are mainly intended for applications requiring simple overcurrent or undercurrent monitoring.

Basic models monitor current in two phases and operate an output contact when the measured value moves outside the set operating range.

Typical requirements include:

• Siemens 3RR2141 current monitoring relay
• Siemens 3RR2142 current monitoring relay
• Siemens 3RR2143 current monitoring relay
• Analogue motor current monitoring relay
• Contactor-mounted undercurrent relay
• Pump dry-run monitoring relay

The exact current range depends on the contactor size. For example, Siemens lists 3RR2141 models for the S00 size with a measuring range of 1.6 to 16 A and 3RR2142 models for size S0 with a range of 4 to 40 A.

Siemens 3RR22 Standard Current Monitoring Relays

The Siemens 3RR22 range provides digital adjustment and more detailed monitoring than the basic 3RR21 series.

Depending on the article number, the relay can monitor three-phase apparent current or active current. The display shows measured values and operating messages, which makes it easier to set the warning and trip limits from the actual machine current.

The standard range can monitor:

• Current overshoot
• Current undershoot
• Current operating range
• Phase failure
• Phase sequence
• Current asymmetry
• Cable interruption
• Motor blocking
• Fault-current conditions
• Warning and shutdown limits

Active-current monitoring can provide a clearer indication of the actual mechanical load over a motor’s operating range. This is useful where the apparent current does not change enough between normal running, low-load, and no-load operation.

Siemens 3RR24 Current Monitoring Relays with IO-Link

The Siemens 3RR24 range adds IO-Link communication to the digital current-monitoring functions.

The relay continues to monitor the load locally, while current values, warning messages and diagnostic information can also be sent to a PLC or higher-level control system.

IO-Link allows:

• Remote adjustment of monitoring limits
• Transmission of actual current values
• Warning and fault diagnostics
• Storage of device parameters
• Faster parameter transfer to a replacement relay
• Operating-hours monitoring
• Switching-cycle counting
• Centralised maintenance information

The 3RR24 can monitor apparent current or active current in three phases. Siemens supplies IO-Link versions in contactor sizes S00, S0 and S2, with current ranges reaching up to 80 A.

Technical Specifications

The Siemens 3RR2 is a product family, so the final specification depends on the complete article number.

• Brand: Siemens
• Product range: SIRIUS
• Series: 3RR2
• Product type: Current and load monitoring relay
• Main use: Monitoring motors and other three-phase loads
• Mounting: Directly onto compatible Siemens 3RT2 contactors
• Alternative mounting: Separate DIN-rail mounting with a terminal support
• Available sizes: S00, S0 and S2
• Typical S00 current range: 1.6–16 A
• Typical S0 current range: 4–40 A
• Typical S2 current range: 8–80 A
• Current measurement: True RMS AC
• Number of monitored phases: Two or three, depending on the model
• Monitoring type: Apparent current or active current
• Setting: Analogue or digital, depending on the series
• Display: Available on digital 3RR22 and 3RR24 versions
• IO-Link: Available on 3RR24 models
• Frequency: 50/60 Hz or an extended 20–400 Hz range on applicable versions
• Control supply: 24 V AC/DC, 24–240 V AC/DC or 24 V DC, depending on the model
• Start-up delay: Adjustable on applicable digital versions
• Trip delay: Adjustable on applicable digital versions
• Reset: Automatic or manual, depending on configuration
• Output contacts: Depend on the selected article number
• Terminal options: Screw or spring-type terminals
• Degree of protection: IP20 at the terminals and enclosure
• Main-circuit current transformers: Integrated within the relay arrangement

The available family sizes and measuring ranges must match the connected 3RT2 contactor and actual load current. Siemens lists 3RR2 products in sizes S00, S0 and S2, covering direct current monitoring up to 80 A.

Features

• Mounts directly onto compatible Siemens 3RT2 contactors
• Requires no separate current transformers for normal direct measurement
• Reduces additional wiring in the motor feeder
• Monitors current overshoot and undershoot
• Detects motor overload and underload conditions
• Can identify pump dry running
• Helps detect broken belts and mechanical couplings
• Monitors phase failure and phase sequence on applicable models
• Current-asymmetry monitoring is available on digital versions
• Detects blocked motors and jammed machinery
• Warning and trip limits can be set separately on applicable versions
• Adjustable start-up delay avoids operation during normal motor starting
• Adjustable trip delay prevents unnecessary switching during brief load changes
• Digital display shows actual current and fault information
• Active-current monitoring provides better load assessment across the motor torque range
• IO-Link versions send values and diagnostics to the controller
• Stored IO-Link parameters simplify replacement
• Screw and spring-terminal options are available
• Suitable for contactor-mounted and separate DIN-rail installation
• Can be used for motors and other electrical loads

Applications

Siemens SIRIUS 3RR2 Current Monitoring Relays are used for:

• Pump dry-run monitoring
• Pump overload monitoring
• Water and wastewater pumping stations
• Industrial compressors
• Air compressors and refrigeration compressors
• Conveyor-belt overload monitoring
• Broken conveyor-belt detection
• Cranes and hoisting equipment
• Industrial fans and blowers
• Mixers and agitators
• Crushers and grinding equipment
• Machine tools
• Packaging machinery
• Material-handling equipment
• Escalators and moving equipment
• Heating-element monitoring
• Industrial ovens
• Motor-driven valves
• Centrifuges
• Cooling systems
• Dust-extraction systems
• Process machinery
• Motor control centres
• Direct-on-line motor starters
• Reversing contactor starters
• Industrial automation panels
• Predictive maintenance systems
• IO-Link motor-load monitoring

The 3RR2 is particularly useful where a change in motor load gives an early indication of a process problem. It can detect conditions such as a pump losing water, a conveyor becoming overloaded or a drive belt breaking before the machine fails. Siemens lists load shedding, no-load operation, overload, heater-function monitoring and phase-sequence problems among the principal applications.

Pump Dry-Run Monitoring

A centrifugal pump normally draws less current when it runs without sufficient liquid.

The 3RR2 can monitor the operating current and issue a trip when it remains below the adjusted limit for longer than the selected delay. This can help prevent damage to seals, bearings and other pump parts caused by dry running.

The start-up delay allows the pump to reach normal operating conditions before undercurrent monitoring becomes active.

A current-monitoring relay should only be used for dry-run protection when the pump’s current changes sufficiently between normal and dry-running conditions. The operating limits should be set from actual measurements taken during commissioning.

Conveyor and Machine-Load Monitoring

A conveyor motor may draw more current when the belt is overloaded, blocked or carrying excessive material. The relay can provide an early warning or stop the conveyor when the current remains above the selected level.

Undercurrent monitoring can also detect a torn belt, broken coupling or loss of load.

For machinery with a large difference between apparent current and actual mechanical load, an active-current monitoring version may provide more reliable load information than a basic apparent-current relay.

Siemens 3RR2 and Overload Relay Difference

A Siemens 3RR2 should not automatically be treated as a replacement for a thermal or electronic motor overload relay.

The 3RR2 current monitoring relay focuses on changes in motor current and driven-process load. It is useful for detecting underload, overload, phase conditions, dry running and mechanical problems.

A 3RU2 or 3RB overload relay provides motor overload protection according to its tripping characteristic and motor current setting.

In many feeders, both devices may be required:

• Overload relay for motor thermal protection
• 3RR2 relay for machine and process-load monitoring
• Motor starter protector or fuse for short-circuit protection

The final protection arrangement should follow the motor, machine and control-panel design.

Selecting the Correct Siemens 3RR2 Relay

A request for “Siemens 3RR2 Current Relay” does not identify the correct product.

For an accurate quotation, share:

• Complete Siemens article number
• Required quantity
• Destination country
• Motor or load current
• Compatible Siemens 3RT2 contactor size
• Apparent-current or active-current monitoring requirement
• Analogue, digital or IO-Link version
• Control supply voltage
• Screw or spring terminals

For replacement requirements, also send a clear photograph of the existing relay label and the connected contactor.

If the part number is unavailable, confirm whether the application involves a pump, conveyor, compressor, heater or another type of load and whether overcurrent, undercurrent or both conditions must be monitored.

Siemens SIRIUS 3RR2 Current Monitoring Relay Supplier and Exporter in India

ARP IMPEX supplies Siemens SIRIUS 3RR2 Current Monitoring Relays for panel builders, machine manufacturers, industrial plants, EPC contractors, maintenance companies and export buyers.

We handle enquiries for:

• Siemens 3RR21 analogue current monitoring relays
• Siemens 3RR22 digital current monitoring relays
• Siemens 3RR24 current monitoring relays with IO-Link
• Siemens current relays for direct mounting on 3RT2 contactors
• Pump dry-run current monitoring relays
• Conveyor overload and underload monitoring relays
• Motor current-asymmetry monitoring relays
• Active-current monitoring relays
• Current relays for blocked-motor detection
• Siemens 3RR2 replacement requirements

The Siemens 3RR2 price depends on the complete part number, contactor size, current range, monitoring functions, control voltage, output arrangement, terminal type and IO-Link requirement.

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