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Wind powered system for generating electricity

  • US 4,565,929 A
  • Filed: 09/29/1983
  • Issued: 01/21/1986
  • Est. Priority Date: 09/29/1983
  • Status: Expired due to Fees
First Claim
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1. A wind turbine system for generating electricity, comprising:

  • a wind turbine rotor;

    a rotor shaft connected to said hub for rotation with said wind turbine rotor;

    a step-up transmission having a low speed input connected to said rotor shaft and a high speed output;

    a rotary pole amplitude modulated induction machine having a rotor that is connected to the output of said transmission, said machine being operable as a generator at a plurality of discreet speeds of rotation;

    wind speed responsive switch means for changing speed of operation of said induction machine; and

    wherein said wind turbine rotor comprises an elongated central hub with no twist having rounded edges and a substantially constant thickness between the edges;

    a pair of fixed pitch essentially straight blades, each blade extending radially outwardly from said hub in a direction diametrically opposite from the other blade;

    each said blade having a mid-section of airfoil cross section positioned radially outwardly of said central hub portion, and a tip section of airfoil cross section positioned radially outwardly of the mid-section;

    each said blade smoothly changing from the substantially constant thickness and rounded edge shape of the central hub portion into an airfoil cross section as it extends radially outwardly from the central hub portion;

    each blade first changing to first a plus twist and then a zero twist and then a minus twist as it extends radially outwardly;

    each said blade tapering in thickness and chord as it extends radially outwardly from a location in its mid-section through its tip section; and

    wherein the tip section of each said blade includes a sculptured tip end portion which decreases in thickness as it extends radially outwardly , said tip portion having an aerodynamic cross-sectional shape which progressively decreases in size, and having a leading edge which progressively sweeps rearwardly.

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