Image Number 5 for United States Patent #7851933.
An input shaft rotates at variable rotation rates and is driven by a variable source of energy or power such as by the propeller of a wind-driven electrical generator. The input shaft is connected to a clutch which is connected to an output shaft and which is operable to rotate the output shaft at a preselected or constant rotation rate. The clutch has a first rotor which electromagnetically interacts with a second rotor to create a torque to cause the second rotor to rotate. The interaction of the first rotor and the second rotor may be varied electrically or mechanically to vary the torque and in turn the rotation rate of the second shaft. The shaft is preferably connected to a synchronous generator; and the rotation rate of the output shaft is controlled so that the generator supplies power at an essentially constant rotation rate.