Energy-efficient drive for the digital enterprise

Companies that work with compressed air invest up to 80 percent of their total costs in the energy needed for this technology. Working with Siemens, Kaeser Kompressoren SE has now developed a new drive that cuts the energy costs from operating compressors by as much as ten percent. The new drive also offers enormous potential for the digital enterprise.

Compressed air guzzles a lot of electricity, even in places you wouldn’t expect: in dentist's offices, for example, where compressed air drives the drill. In other fields, compressed air is used to drive coating machines, clean pipe systems, and inflate plastic blanks into PET bottles like a balloon. 


One of the leading manufacturers of these air compressors is Kaeser Kompressoren SE in Coburg, Germany. Could Carl Kaeser, who founded the company in 1919, ever have imagined in his wildest dreams that nearly 100 years later his mechanical engineering shop would be exporting products to more than 100 countries and be one of the leading industry experts? The fact is that he laid the groundwork for a business that is still being run by his descendants today.

A partnership for a new approach

“We've trusted in our strategic partnership with Siemens for many years: for example, as a supplier of drive systems,” affirms Andreas Birkenfeld, head of the Automation Engineering department at Kaeser. “Products from Siemens have always been a part of new, strategic product development here at Kaeser.” Thomas Horn, who supports Kaeser Kompressoren SE at Siemens, adds: “During the many decades of our partnership, Kaeser has time and again come on board at the very beginning as a pilot customer when we’re working to jointly develop and continuously improve our solutions. We’ve accomplished many things together.”


We’ve accomplished many things together.
Thomas Horn, Siemens AG

New energy-efficient drive

The most recent collaboration combines cutting-edge drive technology with energy efficiency, ecology, and climate protection. The speed-controlled rotary-screw compressors in the ASD series were further developed for this purpose. The synchronous-reluctance motor is optimally adapted to the converter, which results in a drive concept that’s never before been used in the industry. The goal was to increase system efficiency by as much as ten percent in the partial-load range and to simultaneously develop a modified drive system for efficient variable-speed operation. Another goal was to resolutely continue down the road the company has already been traveling in the direction of digitalization.

Cutting energy costs wherever possible

The Kaeser developers were primarily concerned with minimizing the cost of producing compressed air for their customers as much as possible. This means cutting costs at every opportunity. After all, these costs account for approximately 80 percent of all expenditures. Many years ago, long before legal regulations came into play, Kaeser had converted its compressor series to energy-efficient IE3 electric motors. Since then, the company has been working to steadily improve their energy efficiency and effectiveness. 

Data is the raw material for the interesting business models of the future.
Andreas Birkenfeld, Kaeser Kompressoren SE

Climate protection in practice

“It’s our view that systematically increasing efficiency in the partial-load range is a logical consequence of climate protection efforts like those that governments around the world are adopting in their climate protocols,” explains Wolfgang Hartmann, head of Marketing at Kaeser. 


Based on the Simotics GP platform from Siemens, the new standard motor series combines the advantages of both asynchronous and synchronous motors into a single drive: Synchronous-reluctance motors offer the extremely high efficiency of permanently excited synchronous motors. At the same time, there’s no need for expensive precious metals and rare earths in the rotor: Electric steel sheets with special profiling are used instead. This makes the drive robust and easy to service, as is the case with asynchronous motors.

More power, less energy

“It’s crucial to optimally coordinate the motor and variable-speed drive to form an integrated drive system,” explains Birkenfeld. “The innovative aspect is mastering the production engineering of the special rotor geometry for these motors. We’ve also now coded the mathematical engineering model for regulating the motor for use in the variable-speed drive.” In addition to improving energy efficiency by as much as ten percent, this also means increasing the power without changing the size of the drive.

Big data from the drive

The new drive isn't just good for the wallet and the environment – it also performs an important function in digital manufacturing. “We’ve already coupled the variable-speed drive to our control systems,” Birkenfeld says. “The drive system therefore 'sees' the process. This generates a large amount of valuable data that we can use across the board: for example, to analyze and diagnose our system. We’re also working with Siemens on other projects, such as how to obtain data separately right on the motor using additional sensors. It will be interesting to see how this helps us discover new potential for the future digital enterprise. After all, data is the raw material for interesting business models of the future.”


Picture credits: Kaeser Kompressoren

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