Soft Starters – 3RW50


As versatile as your application

SIRIUS 3RW5 soft starter – the next generation


Hybrid switching technology

Hybrid switching technology combines the advantages of electronic control with power semiconductors and the low conducting losses of switching contacts. The strengths of each technology are exploited during the appropriate operating phase. As the motor starts, the soft starter is operated via the power semiconductors, which enable precise and targeted control of the starting current. After the motor has been softly started using semiconductors, the low-loss switching contacts take over the current until the motor is switched off. The hybrid switching technology ensures a longer service life for switchgear due to the reduced wear when switching on. Conventional industrial controls result in wear to the switching contacts every time a system is switched on or off, albeit in very small increments. The result, however, is a limited electrical life. This typical hybrid switching process reduces the starting current of the semiconductor components, thus minimizing the load on the switching contacts to such an extent that the mechanical components in the hybrid switchgear can achieve a significantly longer switching life.

    Benefits of hybrid switching technology.

  • Lower power losses in the operating phase.
  • Lower energy costs and heat rise in the control cabinet.
  • Avoidance of current peaks.
  • No network voltage dips.
  • Less flicker.
  • Particularly economical for increased switching cycle counts.
  • Low-wear switching thanks to hybrid switching technology.

Ready for a digital future

Data whenever and wherever needed

The digital transformation of industry is in full swing and our latest generation of soft starters supports companies in fully embracing the potential of digitization. This is particularly beneficial when it comes to economic efficiency, making it faster and easier to achieve optimum results, with permanently high availability thanks to shorter downtimes.

Digitalization requires far simpler processes and time savings in the planning and configuration phases. The wide digital availability of product data considerably simplifies the process of putting together the required devices; and parameterization can be completed a lot quicker. This also shortens on-site commissioning times.


Machine and plant data is readily available at all times, delivering greater transparency. This means you can avoid plant downtimes and increase cost-effectiveness. The soft starters can transfer data to the cloud, enabling flexible use both directly at the switchgear as well as at the management level. Analyses and benchmarking allow you to determine the energy consumption of your equipment and use the findings to optimize your processes.

Planning and engineering

All of the product data is available digitally and can be integrated into popular engineering tools. You can put together the products for your project using the TIA Selection Tool as a configurator – either on a Windows PC or on mobile devices with the browser-based cloud version. You can use the Simulation Tool for Soft Starters (STS) to select devices for your application. The selection is automatically transferred to the Siemens Industry Mall for ordering via a link.


The SIRIUS Soft Starter ES software in the Totally Integrated Automation Portal (TIA Portal) enables you to quickly and easily perform parameterization and monitoring as well as diagnostics in the event of servicing SIRIUS General and High Performance soft starters. The device parameters can be set directly on the PC and transferred to the soft starter via an Ethernet cable or a PROFIBUS/PROFINET connection.

The soft starters can be easily and securely connected to cloud-based solutions, such as the cloud-based, open IoT operating system, MindSphere. This gives you access to the operating data across all systems and allows you to analyze it. The results are protected against manipulation and can be used for predictive maintenance, energy data management and resource optimization.

3RW5 Accessories

SIRIUS 3RW5 Accessories

SIRIUS 3RW5 Operating Panels

SIRIUS 3RW5 Standard HMI

SIRIUS 3RW5 High-Feature HMI

SIRIUS 3RW5 with PROFIBUS Communication

SIRIUS 3RW5 Communication Modules