Quality turbine bearings for wind energy in Holland With renewable energy very much a hot topic, an American bearings specialist received largest ever order in this application sector. Involved in wind energy for more than 20 years, Kaydon has developed a range of bearings that best meet critical pitch, yaw and gearbox applications in land-based or offshore systems from 200kW to 5MW and beyond. The typical requirement is for a large slewing ring - a large diameter bearing with a large bore - in diameters ranging from 2 to 5m. To combine the function of a bearing and gear, teeth can be cut into the inner or outer race to rotate with the assembly or remain stationary in respect to the ground during operation. The use of a single larger diameter bearing allows wiring and other services to pass through the bore with ease. This simplifies the overall system design, improves outward appearance and protects components. Selecting the right bearing design depends on load, stiffness, speed, size and the smoothness of rotation required. One that has proven to be particularly popular for wind turbines however is the four-point contact ball bearing. This bearing accepts combinations of radial, thrust and moment loads. It uses races shaped as gothic arches on both the inner and outer race ball paths that generate four points of contact on each ball. To satisfy requirements for maximum load capacity within a given envelope, especially in larger sized bearings, Kaydon has also developed an eight-point contact bearing that is also widely used in wind turbines. This is an annular bearing with two rows of balls whose unique feature is its use of the gothic arch internal geometry in both rows. Tests have confirmed that this additional row increases load capacity by an additional 80%. Naturally, corrosion resistance is an important consideration for outdoor use and the wind turbine bearings are therefore available with a range of surface treatments to meet the conditions of the application. Selection of the most appropriate materials is also critical for operating temperatures that may be as low as -40°C; unique sealing arrangements are available for severe conditions. Speed Link InfoService Request more information by e-mail Reader Service No. Reader Number Email Address 00937

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