Abstract: A system for generating alternating current of selected voltage at a target frequency includes a plurality of A.C. generators, at least one of which has a rotatably mounted stator. A prime mover drives a power input shaft at speeds extending through a wide range and the shaft is connected to the first rotor. As speed increases, the generator reaches the desired frequency and a sensing device releases the stator to rotate and maintain a relative speed between itself and the rotor corresponding to the target frequency. The stator drives the second rotor at its own absolute speed which is the difference between the power input shaft speed and the relative speed between the first stator and rotor. A field control maintains the desired voltage and a load control transmits the current output to a load and varies the load to maintain the generator at proper operating condition.

Abstract: A turbine type power generator includes a rotor having a vertical shaft to drive a load which may be an electric generator or mechanical gear train or other device for using or transmitting power. Generally vertically extending blades are secured at their ends to the rotor shaft and are set at an angle to the relative wind to be driven thereby. The rotor is surrounded by wind controlling shield means through which the air flow passes to contact the blades in the proper direction for causing rotation. The free flow air inlet area is substantially less than the maximum projected area of the shield means normal to the relative wind so that the total wind trapped must flow through a reduced area with a consequent increase in velocity to impart more energy to the rotor blades. One form of shield means is a structure of the same general shape as the rotor surrounding the rotor on all sides and having vertically extending passages spaced around its perimeter to lead the air flow to the blades.