| CPC F03D 13/35 (2016.05) [F03D 7/02 (2013.01); F03D 7/0224 (2013.01); F05D 2260/15 (2013.01)] | 18 Claims |
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1. A method for balancing a wind turbine where the wind turbine comprises:
a rotor hub mounted on a nacelle for rotation about a generally horizontal rotor axis;
a plurality of blades mounted on the rotor hub for driving the rotation of the rotor hub about the rotor axis in response to wind impacting on the blades;
each blade being mounted on the rotor hub by an annular blade bearing which allows the blade to pivot about a longitudinal axis of the blade to change pitch of the blade as required for wind conditions;
the method comprising:
in response to a detection of an imbalance in the rotation of the rotor hub caused by unbalanced loads applied by the blades to the rotor hub, adding weight to the wind turbine at a selected one of the blades to counter the imbalance;
where the weight is added by mounting a weight body to the wind turbine at the blade bearing of said selected blade;
wherein the annular blade bearing includes a circular inner race surrounding the longitudinal axis of the selected blade and lying in a radial plane of the longitudinal axis and a circular outer race radially outward of and surrounding the inner race;
wherein the outer race is attached to the hub and the inner race is attached to the selected blade so as to pivot about said longitudinal axis with said selected blade;
and wherein the weight body is mounted on the outer race outwardly of the inner race and at least partly surrounding the inner race.
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