When it comes to controlling motors in automation technology, one device is irreplaceable: the contactor. In Siemens’ Industry Sector, the engineer Manuela Lüftl (48) specializes in developing contactors for a wide range of output classes. These contactors are part of the Sirius range of industrial switching technology products from Siemens. After managing a development department in India for two years, Luftl recently returned to the plant in Amberg, Germany.

Like relays, contactors are used to remotely switch circuits. However, contactors are designed to handle much higher loads than relays — up to several hundred kilowatts. Along with circuit-breakers, contactors are needed to control motors in mechanical engineering applications, in lifting and conveyor technology, and in the automotive and steel industries. Contactors have been around for about one hundred years, and Siemens is enhancing them continuously. Together with associated systems such as switches, a new generation of contactors is launched on the market about every ten years. Because Siemens’ state-of-the-art switches are extremely energy-efficient, they consume little energy and generate low amounts of waste heat in the control cabinets. The resulting drop in cooling needs leads to even more energy savings.

Before going to India, Lüftl worked at the Siemens plant in Amberg, Bavaria, where she was extensively involved in the development of the latest generation of contactors right from the start. Prior to that, she had worked in Amberg for four years as a plastics expert for low-voltage systems. She had also majored in plastics technology during her studies at Rosenheim University of Applied Sciences. Ever since she switched to the design department in 1994, Lüftl has continually submitted inventions for low-voltage switching systems. To date, she has registered a total of 41 individual patents, which are protected in 18 patent families.

Her invention of a special arrangement of the quenching plates in the arc chamber is an important innovation. The plates extinguish the arc that is created when a contactor is switched at high outputs. From the very start, Lüftl was involved in the development of a new generation of contactors that has a greater performance range than its predecessors. Areas in which the new contactors are used include motors for the automotive, steel, and mechanical engineering applications. In addition, the contactor is easier to plug in than ever before, thanks to a new modular system and perfectly coordinated, flexibly combinable components. Once the device has been inserted, that’s it! Complicated wiring is thus a thing of the past, as is the risk of wiring mistakes. Lüftl had co-responsibility not only for the modular system’s entire development process, but also for its accessories. “I work closely with many different departments that are responsible for everything from specifications and prototype development to certification,” she explains. Even in her youth Lüftl already knew that she would one day pursue a technical career “because I was always good at math, physics, and chemistry.” She was especially attracted to engineering, since it requires imagination and creativity to turn a sketch into a product.

New challenges have always represented an incentive to her, which is why she enthusiastically accepted an offer two years ago to create a Siemens development department in India as part of the Industry Sector. “Of course it was a huge transition to move from the small town of Amberg to the city of Mumbai, which has approximately 18 million inhabitants,” she says. India has great strategic importance for Siemens as a development location. “Whereas in the past new developments generally came from Germany and were adapted to the local conditions in India, more and more innovations have been created on the subcontinent in recent years,” explains Lüftl. In India, her task was to align the department structure and the processes for new developments with those in Germany. “To ensure effective communication between the different development locations, you have to make sure that everyone knows exactly how development work proceeds,” says Lüftl. She finished her work in the fall of 2012, when she handed over the department to an Indian colleague. Luckily, Lüftl didn’t have to do without a family life while she was abroad. Happily, her husband was able to combine his professional duties in such a way that it was possible for him to spend half of the year with her in India. Although she and her husband were unable to indulge in their hobbies of mountain climbing and bicycle riding in the huge city of Mumbai, they did make several interesting trips to various regions of India. Since her return to Amberg, Lüftl has been in charge of the manufacturing planning and test planning of electronic products.
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