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SOFT STARTERS FOR RUNNING THREE-PHASE MOTORS

Siemens Sirius 3RW30/3RW31


This is the easiest and most affordable in the 3RW range. It is designed to start no-load or low-load motors (the most common applications are fans, conveyors, agitators, grinders, etc.). The starters in this series do not have integrated drive current protection.

Key features:

  • designed for motor outputs of up to 55 kW (at 400 V)
  • compact design, saving space in the control cabinet (e.g. at 22 kW the width is only 55 mm, as opposed to approximately 178 mm for the Y/D contactor combination, i.e. a 70% saving of space), and only three cables are needed for the motor
  • quick assembly of the fuseless motor feeders by adding a 3RV circuit breaker
  • quick assembly of fused motor feeders in combination with thermal or electronic 3RT overload relay
  • two-phase control
  • adjustable start and stop times
    • in the range 0 to 20 s
  • adjustable start voltage value
    • 40% to 100% of rated voltage
  • 2 x output relay for status indication
  • integrated bypass to save energy
  • choice of control voltage
    • 110 to 230 V or 24 V (e.g. for PLC control)
  • this series of soft starters can be purchased in our e-shop


Want to find out more? Download the complete catalogue.

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Siemens Sirius 3RW40


These soft starters are distinguished from the more affordable 3RW30/31 series by integrated overload protection of the electric motor and larger power range. Their intended purpose is largely the same as for the 3RW30/31 series of soft starters.

Key features:

  • for motor outputs of up to 250 kW (at 400 V)
  • compact design
    • save space in the cabinet (approximately 50% space saving compared to the Y/D contactor combination)
    • in addition, only three cables are needed for the motor
  • integrated soft starter and electric motor protection
    • the same set-up and reset system as the 3RV circuit-breakers
  • adjustable start and stop times
    • in the range 0 to 20 s
  • adjustable start voltage value
    • 40% to 100% of rated voltage
  • 2 x output relay for status indication
  • integrated bypass to save energy
  • choice of control voltage
    • 110 to 230 V or 24 V (e.g. for PLC control)
  • this series of soft starters can be purchased in our e-shop




Siemens Sirius 3RW44


A “high feature” group of starters that are also suitable for heavy-duty start-ups with three-phase control. Premium equipment, simple operation and extensive diagnostics – the 3RW44 series in a nutshell..

Key features:

  • with standard wiring – for motor outputs of up to 710 kW (at 400 V)
  • with triangle wiring – for outputs of up to 1,200 kW (at 400 V)
  • graphic display with control buttons to set and display values and error messages
  • integrated softstarter and electric motor protection
    • the same set-up and reset system as the 3RV circuit-breakers
  • possibility of connecting a communication module for Profibus-DP
  • torque control and adjustable current limitation
  • possibility of dynamic DC braking
  • adjustable start and stop times
    • in the range 1 to 360 s
  • adjustable start voltage value
    • 20 % to 100% of rated voltage
  • integrated bypass to save energy
  • control voltage
    • 110 to 230 V or 24 V (e.g. for PLC control)
  • available in the e-shop






More details on selecting drives and the features of each component can be found in the support section.
Alternatively, get in touch and we’ll be happy to advise. 

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