Abstract: A wind turbine includes a rotor shaft having thereon rotor blades exposed to wind energy, a first stage gear set on the rotor shaft, a discretely variable ratio gear set coupled to the first stage gear output shaft and having a gear set output shaft, a differential on the gear set output shaft having a differential control shaft facilitating changing the gear box ratio by whole numbers of gear teeth, and a generator operating at a constant frequency coupled to an electric grid operating at the constant frequency. The wind turbine may take a variable speed input of the gear box to create a fixed speed output fed to the generator operating at constant frequency and coupled directly to the power grid without power electronics. Existing wind turbines whether fixed speed fixed pitch or variable speed variable pitch can be retrofitted with the gear box of the present invention.

Abstract: An assembly for retrofitting fixed speed, doubly fed and fully converted wind turbines. A differential having an output shaft coupled to the main generator and a control shaft to change a ratio between differential input and output and coupled to the auxiliary generator. The main generator operates at constant frequency and is coupled to an electric power grid without a power converter. A variable speed auxiliary generator may be coupled to the electric grid through auxiliary power electronics. A controller may during low loads assign a full load to the auxiliary generator, during typical loads assign a variable shared load between the auxiliary and main generators based on an optimization algorithm and during high loads assign a fixed shared load between the auxiliary and main generators based on the internal gear ratio of the differential. For step-down differentials, at high loads the full load may go to the main generator.

Abstract: An assembly for retrofitting fixed speed, doubly fed and fully converted wind turbines. A differential having an output shaft coupled to the main generator and a control shaft to change a ratio between differential input and output and coupled to the auxiliary generator. The main generator operates at constant frequency and is coupled to an electric power grid without a power converter. A variable speed auxiliary generator may be coupled to the electric grid through auxiliary power electronics. A controller may during low loads assign a full load to the auxiliary generator, during typical loads assign a variable shared load between the auxiliary and main generators based on an optimization algorithm and during high loads assign a fixed shared load between the auxiliary and main generators based on the internal gear ratio of the differential. For step-down differentials, at high loads the full load may go to the main generator.

Abstract: A wind turbine includes a rotor shaft having thereon rotor blades exposed to wind energy, a first stage gear set on the rotor shaft, a discretely variable ratio gear set coupled to the first stage gear output shaft and having a gear set output shaft, a differential on the gear set output shaft having a differential control shaft facilitating changing the gear box ratio by whole numbers of gear teeth, and a generator operating at a constant frequency coupled to an electric grid operating at the constant frequency. The wind turbine may take a variable speed input of the gear box to create a fixed speed output fed to the generator operating at constant frequency and coupled directly to the power grid without power electronics. Existing wind turbines whether fixed speed fixed pitch or variable speed variable pitch can be retrofitted with the gear box of the present invention.

Abstract: A variable diameter gear device for variable ratio transmission systems has a displaceable gear tooth sequence formed from interconnected gear teeth with uniform pitch lying on a virtual cylinder coaxial with an axle of the device. A torque linkage transfers a turning moment between the axle and the gear tooth sequence. A diameter changer includes at least one disc with a spiral track to which each of the gear teeth is linked. Rotation of the discs relative to the axle causes variation of an effective diameter of the virtual cylinder while the gear tooth sequences remain on a virtual cylinder centered on the axis and the uniform pitch remains constant.

Abstract: Apparatus for use in a variable ratio transmission has gear teeth (12) formed for engaging a facing gear wheel, each having a plane of symmetry (P) parallel to a width of the tooth. Links (30) rigidly associated with the gear teeth are sequentially interconnected to form hinge joints (32) between adjacent pairs of gear teeth, thereby forming a gear tooth sequence (11). The hinge joint (32) for each pair of adjacent gear teeth has an axis of rotation (34) lying on a plane (B) bisecting an angle between the planes of symmetry (B) of the adjacent gear teeth.

Abstract: A variable diameter gear device for use in a variable ratio transmission system includes a gear tooth set deployed around an axle which defines an axis of rotation. The gear tooth set includes at least two displaceable gear tooth sequences, each including a multiple gear teeth spaced at a uniform pitch, and a diameter changer mechanically linked to the axle and to the gear tooth set. The diameter changer is deployed to transfer a turning moment between the axle and the gear tooth set, and to displace the gear tooth set so as to vary a degree of peripheral coextension between the gear tooth sequences. Specifically, the diameter changer transforms the gear device between at least two states in which the gear tooth set is deployed to provide an effective cylindrical gear with differing effective numbers of teeth. The gear device may be used either in direct engagement with another gear wheel or as part of a chain-based transmission system.