Component fatigue strength testing on a down-scaled cast iron wind turbine gearbox planet carrier

Abstract The trend towards higher power ratings in wind turbines (WT), driven by the increasing demand for cost competitive renewable energy, has resulted in a steady increase in turbine size and weight, since the increase in power also results in higher mechanical loads on the drive train. Consequently, all components of the drive train must be enlarged to withstand the higher loads. Ensuring the safe and reliable operation of WTs is one of the most important priorities since damage leads to high repair costs and yield loss due to downtime. To achieve reliability, system and component tests are one effective method since they enable the quantification of the components’ strength with the real geometry and the real loads. However, conducting these tests can be resource-intensive and challenging due to the extreme dimensions especially in terms of the required test equipment. One way to cope with this challenge is do the tests with scaled down versions of the devices under tests on smaller test equipment. This study investigates the feasibility of down-scaled component testing to determine more realistic component fatigue strengths of the planet carrier compared to the values of material standards. For this purpose, a WT gearbox planet carrier was scaled down to a quarter of its original size in order to investigate its critical section. This reduction in size results in a material saving of approximately 95% per test specimen and a load reduction of 99% compared to the original planet carrier. However, the investigation also highlights potential limitations in the manufacturing process and the transferability of the results back to the component in original size.