They are in use around the clock: large gearboxes in wind turbines. The various system components are subject to different loads depending on the weather conditions. However, fault-free and safe operation of the components is a prerequisite for the gearbox to run reliably. In order to guarantee this reliability, regular maintenance of the plants and their systems is planned and also included in the price. However, unscheduled maintenance is very expensive because the operating downtimes cannot be planned.

Test gearbox on the test bench.

© Institute for Machine Elements (IMA), University of Stuttgart

A significant problem in gearboxes is material fracture caused by fatigue, which is known as "pitting" and can grow over time until the tooth flank breaks. Until the flank of the damaged tooth breaks, the other teeth usually remain undamaged. Pitting occurs primarily in case-hardened gears, such as those typically used in wind turbines.

The Institute of Machine Elements (IMA) at the University of Stuttgart, under the direction of Dr.-Ing. Martin Dazer, has developed a monitoring and control system that detects damaged gears in gearboxes and simultaneously relieves the load so that the overall performance of the wind turbine is maintained. With the help of sensors, the system detects topographical changes on the surface of the gears and initiates a targeted reduction of the load. This is implemented by actuators.

A patent application has been filed for the invention (EP 3604803 B1 granted; US 2020/0040987 A1 granted). The scientists were supported by the Technology License Bureau (TLB) in patenting and marketing the current development. TLB is also responsible for the exploitation of this technology and offers manufacturers licensing options.