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New generation of soft starters for simple to demanding drive requirements

New generation of soft starters for simple to demanding drive requirements.

The new harmonized Sirius 3RW5 soft starter generation offers the right hardware for all requirements as well as individual expansions such as operator panels with and without display (HMIs), or communication via Profinet/Profibus and Modbus. The devices are suitable for global use thanks to numerous certificates and approvals such as IEC, UL and CSA. Tested combinations for the entire motor feeder extend the range of possible uses. The compactly designed enclosure, which won the if-design award 2018, and the coated printed circuit boards contribute to a space-saving and rugged control panel assembly.
The new Sirius 3RW5 soft starters can be used in a host of applications thanks to specific functions – from pumping, ventilating and compressing, to moving and processing. In addition, they feature special functions such as starting time monitoring, automatic parameterization depending on motor startup, pump stop to avoid pressure peaks in piping systems, and condition monitoring with warning and alarm limits. They are also designed to be electrically rugged to fluctuations in line voltages.
The new Sirius 3RW5 soft starter generation is fitted with modern hybrid switching technology to ensure efficient switching and energy-saving operation. This enables low-wear switching, extends the service life of the devices and provides mechanical protection for the drive train. The soft starting ensures that the devices avoid current peaks in the power supply system. All in all, using the new Sirius 3RW5 devices enhances the reliability of the application and increases the cost efficiency of the system.
A further advantage when using the new 3RW5 generation of soft starters is the provision of data, for CAx tools like Eplan, for example. In addition, the Simulation Tool for Soft Starters (STS) helps the user to make a simple product selection. The new 3RW5 soft starters can be configured and commissioned easily and in a standardized manner in the TIA Portal using the Soft Starter ES engineering software. They are simply linked up to the automation system by means of the various communication options.

Background information:
Soft starters limit the starting current and starting torque of drives and electric motors. In this way, mechanical loads and voltage dips in the line can be reduced. The motor voltage is then reduced using phase control and is increased from an adjustable starting voltage up to the desired line voltage within a specific ramp time. The motor is adjusted to the load characteristic of the driven machine by means of stepless control of the voltage supply. Soft starting and stopping reduces the load on connected equipment, and this supports smooth production. Mechanical components are accelerated gently, thus positively influencing operating characteristics, and extending service life.

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Siemens AG (Berlin and Munich) is a global technology powerhouse that has stood for engineering excellence, innovation, quality, reliability and internationality for 170 years. The company is active around the globe, focusing on the areas of electrification, automation and digitalization. One of the world's largest producers of energy-efficient, resource-saving technologies, Siemens is a leading supplier of efficient power generation and power transmission solutions and a pioneer in infrastructure solutions as well as automation, drive and software solutions for industry. The company is also a leading provider of medical imaging equipment – such as computed tomography and magnetic resonance imaging systems – and a leader in laboratory diagnostics as well as clinical IT. In fiscal 2017, which ended on September 30, 2017, Siemens generated revenue of €83.0 billion and net income of €6.2 billion. At the end of September 2017, the company had around 377,000 employees worldwide. Further information is available on the Internet at
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Gerhard Stauss

Siemens AG

Gleiwitzer Str. 555
90475 Nuremberg

+49 (911) 895-7945