High-reliability roller bearings reduces operation costs for wind turbines
Among the latest trends for roller bearings in wind energy plants is the employment of application-specific special materials and designs, the integration of roller bearings into drive components as well as the realistic simulation and calculation of the durability during operation. All trends are following the goal to achieve highest possible durability and the reduction of overall operation costs.
Wind technology is one of the most sophisticated applications for roller bearings. The bearings are often very large and are exposed to high dynamic forces. In addition, the environmental conditions are disadvantageous for these precision components of the drive technology.
Under these conditions of use, the design life of wind energy plants of 175,000 hours or 20 years is a big challenge for roller bearing developers with respect to hardly accessible bearings. Aggravating to this is that there are specific damage symptoms against which precautions must be taken. Furthermore, the latest projects demand an even longer durability than the industry expected norm of 20 years.
Adapting quality standards
As one of the international “top three” of the roller bearing manufacturers, NSK offers a comprehensive range of roller bearings specially developed for use in wind energy plants. In 2003, NSK developed the range of rolling bearings for this industry and named it as “Wind Standard U303”. Since then, the company has continued developing the range of bearings and standard in line with the market and industrial requirements.
The high costs for replacing the components in the “uptower” drive train of on-shore plants and off-shore wind parks mean that high-quality roller bearings are of vital importance to wind turbines. During Wind Energy, Hamburg, in 2016, NSK showcased their “Wind Standard U303”, highlighting the changes that had been made in line with these specific industry enhancements.
The basis here is the traceability of all components of each individual bearing labelled with a serial number. All relevant process parameters – from steel melting via machined processing and heat treatment until assembly – are securely stored for a 20-year period. In addition, non-destructive examinations to prevent grinding burns, surface defects and structural disorders within the material are carried out. Further important modules are documentation, process security, conservation, packaging and accurate checks to prevent contamination with small dirt particles.