Valmet gearboxes in Vestas wind turbines have not shown signs of "pitting," as stated in our caption last month ("Retrofit of hundreds of Danish turbines, Windpower Monthly, May 1999), but only signs of "normal wear," says Vestas service head, Hans Laurids Pedersen. Vestas is to replace about 10% of the bearings on the 880 Vestas wind turbines in operation with Valmet gearboxes, which are now being examined by Vestas and Valmet, he says. The bearings will be upgraded to help prevent damage.
The risk of gearbox damage is also smaller than feared, adds Pedersen Over a two-and-a-half year period, Vestas has made six monthly checks of Valmet gears on 22 wind turbines in Italy, the oldest Vestas turbines operating with Valmet gearboxes. Laurids Pedersen says these gearboxes are still "as new" today.