Patent attributes
Apparatus and method for tuning the magnetic field of windmill generators to obtain efficient operation over a broad RPM range. The windmill generator includes fixed windings (or stator) inside a rotating rotor carrying permanent magnets. The permanent magnets are generally cylindrical and have North and South poles formed longitudinally in the magnets. Magnetically conducting circuits are formed by the magnets residing in magnetic conducting pole pieces (for example, low carbon or soft steel, and/or laminated insulated layers, of non-magnetizable material). Rotating the permanent magnets, or rotating non-magnetically conducting shunting pieces, inside the pole pieces, either strengthens or weakens the resulting magnetic field to adjust the windmill generators for low RPM torque or for efficient high RPM efficiency. Varying the rotor magnetic field adjusts the voltage output of the windmill generators allowing the windmill generator to maintain a fixed voltage output.
