Lagerwey from Barneveld has been producing innovative wind turbines since 1979. They wanted to be able to build turbines with a remote-controlled crane. During construction, this crane had to be able to climb up the mast of the wind turbine. With this idea and a drawing they came to MechDes.
We then developed the idea into a design, a crane for building the turbines. This crane climbs up the mast of the wind turbine. The crane can lift 60 tons at a distance of 6 meters.
Within the ‘wind energy’ sector, large wind turbines are the trend. However, the installation of these giants is becoming increasingly complex. For example, installing a multi-megawatt wind turbine with a hub height of more than 150 meters requires a large and expensive crane. The transport of such a crane can only be done in parts and that requires the deployment of many trucks. Assembling and disassembling a crane takes several days. Because assembly takes place horizontally, the availability of a large and flat site is necessary, as well as a solid foundation.
In a project like this, half of the engineering consists of making calculations. First of all, the load capacity of the crane had to be identified. In addition to the normal loads, such as lifting and climbing, the crane also had to withstand a severe storm of more than 12 Beaufort. The design, including calculations, had to be approved by an official body, who also checked whether the crane would be built according to the correct specifications. In most cases we used FEA (Finite Element Analysis) with Ansys to check the stress and stability. The strength of the bolted connections, steel cable and bearings was also calculated. In addition, the dynamic behavior during lifting and slewing of the load on the steel cable was analysed. To minimize the weight of the crane for transportation and to reduce the force exerted on the wind turbine, we mainly used high-strength steel. The steel had a tensile strength of 690MPa or even 770MPa. That is two to three times higher than normal steel!
We also designed the winch. This contains 1600 meters of Ø19 millimeter steel cable in 7 layers. For good winding, the winch drum was equipped with Lebus grooves. The crane can be transported by just three trucks and assembled within one day. It is the world’s first wind turbine climbing crane and it will change the way turbines are built!
Facts & Figures
The patented crane is currently under construction and will be tested in early 2018.