Patent ID: 8622869

Claim:
In a wind driven turbine, having a plurality of rotatable blades and a transmission drive, the transmission drive comprising: a rotatable gear drive for supplying power from the wind driven turbine to at least one single generator; and at least two compound differential planetary gears, a first differential planetary gear coupled to a rotor main shaft and operatively engaged with an output gear and a second differential planetary gear mounted concentric with the second differential planetary gear, and operatively engaged with the output gear, the compound differential planetary gears each comprising: an input sun gear driven by the rotor main shaft; two divided output internal ring gears and two stiff ring gears formed as one piece surrounding the input sun gear, the output internal ring gears coupled to an external drive to effect rotational drive; two fixed reaction external gears on both sides of the input sun gear with the same number of teeth and coaxial with said input sun gear; and a plurality of planet gears each disposed between the reaction external gears and the input sun gear on one side and the output internal ring gears on the opposite side, said planet gears engaging the reaction external gears at axially spaced locations, the drive ratio between the planet gears and the output ring gears being different from the drive ratio between the planet gears, the reaction external gears and the input sun gears.