Twenty-five years ago, Ziehl-Abegg laid the foundations for the launch of energy-saving EC motors in ventilation technology. The company says this came as the result of Germany's telephone exchanges changing to digital technology. The new technology required safe and reliable cooling of the operating rooms. The Austrian post and telegraph administration service (the forerunner of today's Telekom Austria) also moved to modern technology in the 1990's.
The call for tender by the Deutsche Bundespost (predecessor of today's Deutsche Telekom) paved the way for the use of EC motors. Until then, fans in ventilation systems were driven using uncontrolled asynchronous motors. The first attempt to significantly reduce power consumption was the use of frequency converters as a control device.