Abstract: An apparatus includes a lighter than air platform, a reversible propulsive/wind turbine, a deployable anchor to constrain movement of the lighter than air platform with respect to an anchor point allowing wind to drive the turbine, and a generator/motor coupled to the turbine to produce electrical power when movement of the lighter than air platform is constrained. A method performed by the apparatus is also provided.

Abstract: An apparatus includes a lighter than air platform, a reversible propulsive/wind turbine, a deployable anchor to constrain movement of the lighter than air platform with respect to an anchor point allowing wind to drive the turbine, and a generator/motor coupled to the turbine to produce electrical power when movement of the lighter than air platform is constrained. A method performed by the apparatus is also provided.

Abstract: An apparatus and method for controlling the speed of rotation of a shaft. A sensor senses the speed of rotation and generates a first signal representative of the sensed speed. A controller compares the first signal with a second signal representative of a predetermined speed and generates an error or control signal representative of the comparison. The control signal is fed to the field of an alternator in such manner that the field of the alternator increases as the sensed speed increases over the predetermined speed. The field of the alternator opposes rotation of the alternator shaft. The alternator shaft is operatively associated with the shaft whose speed is being controlled so that the increase in alternator field force results in the application of a braking force on the shaft to thereby reduce its speed of rotation to the desired speed. As the shaft's speed approaches the desired speed, the alternator field force is decreased so as to prevent reduction of the shaft's speed below the desired value.