초록 ▼

A fixed pitch wind turbine rotor (18) is teeter mounted (76, 78, 80) onto a low speed input shaft (44) which is connected to the input (58) of a step-up transmission (46). The output (48) of the transmission (46) is connected to a rotary pole amplitude modulated induction machine (42) which is opera

A fixed pitch wind turbine rotor (18) is teeter mounted (76, 78, 80) onto a low speed input shaft (44) which is connected to the input (58) of a step-up transmission (46). The output (48) of the transmission (46) is connected to a rotary pole amplitude modulated induction machine (42) which is operable as a generator at a plurality of discreet speeds of rotation and is also operable as a startup motor for the rotor. A switch (45) responsive to the rotational speed of the wind turbine rotor switches the generator from one speed of operation to the other. The rotor hub (72) and the inner body portions (71) of two blades (68, 70), which extend radially outwardly in opposite directions from the hub (72), are constructed from steel. The outer end portions (73) of the blade (68, 70) are constructed from a lighter material, such as wood, and are both thinner and narrower than the remainder of the rotor. The outer end section (73) of each blade (68, 70) includes a main body portion and a trailing edge portion (104) which is hinge-connected to the main body portion. Each blade (68, 70) includes a centrifugal force operated positioning means (98, 100) which normally holds the drag brake section (104) in a retracted position, but operates in response to a predetermined magnitude of centrifugal force to move the drag brake (104) section into its deployed position. Each blade has an airfoil cross section and each blade (68, 70) has a plus twist inner portion adjacent the hub (72) changing to first a zero twist and then a minus twist as it extends radially outwardly from the hub (72).

대표청구항 ▼

1. A fixed pitch wind turbine rotor adapted to be mounted for rotation by the wind about a generally horizontal axis, comprising: an elongated central hub portion with no twist having rounded edges and a substantially constant thickness between the edges; a pair of fixed pitch blades, each blade

1. A fixed pitch wind turbine rotor adapted to be mounted for rotation by the wind about a generally horizontal axis, comprising: an elongated central hub portion with no twist having rounded edges and a substantially constant thickness between the edges; a pair of fixed pitch 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; and each said blade tapering in thickness and chord as it extends radially outwardly from a location in its mid-section through its tip section. 2. A wind turbine rotor according to claim 1, wherein the tip section 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, and a relatively flat back surface. 3. A wind turbine rotor according to claim 1, wherein the airfoil profile of each blade changes as the blade extends radially outwardly, from a substantially NACA 23028 airfoil profile at plus twist, to a substantially NACA 23023 airfoil profile at zero twist, to a substantially NACA 43018 airfoil profile at zero twist, to a substantially NACA 43012 airfoil profile at minus twist. 4. A wind turbine rotor according to claim 1, comprising an all-steel welded hub portion, and wherein each blade comprises an all-steel welded mid-section and a laminated wood outer end section. 5. A wind turbine rotor according to claim 4, wherein each tip section includes a fixed position blade tip. 6. A wind turbine rotor, comprising: a hub; a pair of fixed pitch blades, each blade extending radially outwardly from said hub in a direction diametrically opposite from the other blades, each blade including a fixed pitch mid-section of airfoil cross section and a fixed pitch outer end section of airfoil cross section having a front surface and a back surface; at least one of said fixed pitch outer end sections comprising a main portion including a leading edge for said section, and a drag brake forming, trailing edge portion having a generally triangular cross-sectional shape and an apex region; hinge means hinge-connecting said apex region to said main portion, for pivotal movement of the trailing edge portion relative to said main portion, between a retracted position in which it forms a streamline trailing edge for said outer end section and a deployed position in which it extends generally across the chord of the outer end section and functions as an aerodynamic drag brake, and said trailing edge portion having a first side surface which forms a part of said front surface when the trailing edge portion is retracted, and which extends generally laterally of said front surface when the trailing edge portion is deployed, and a second side surface which is concealed against the main portion when the trailing edge portion is retracted, and which extends generally laterally of the back surface when the trailing edge portion is deployed, and a base surface which is a part of the back surface when the trailing edge portion is retracted, and which extends generally laterally of the outer end section when the trailing edge portion is deployed. 7. A wind turbine rotor according to claim 6, comprising a centrifugal force positioning means normally holding the drag brake in its retracted position, but operating in response to the development of a centrifugal force of a predetermined magnitude to move said drag brake into its deployed position. 8. A wind turbine rotor according to claim 7, wherein the positioning means for the drag brake comprises weight means mounted in the wind turbine rotor for radial translation between an inner position and an outer position, and linkage means interconnected between the weight means and the drag brake, said linkage means holding the drag brake in its retracted position when the weight means is in its inner position, and said linkage means holding the drag brake in its deployed position when the weight means is in its outward position. 9. A wind turbine rotor according to claim 8, comprising a releasable lock member having a lock position in which it locks the weight means in its inner position, and a centrifugal force operated trigger means for moving said lock member into an unlocked position in response to a centrifugal force of a predetermined magnitude, with said weight means being free to move radially outwardly from its inner position to its outer position, in response to centrifugal force, when the lock member is in its unlocked position. 10. A wind turbine rotor according to claim 8, further comprising spring means for normally biasing the weight means radially inwardly, said spring means functioning to move the weight means from its outer position into its inner position when centrifugal force acting on said weight means drops below said predetermined magnitude. 11. A wind turbine rotor according to claim 10, comprising a second lock member for holding the weight means in its outer position, in opposition to the force of the spring means, and means for unlocking said second lock member when the centrifugal force on the trigger mechanism drops below a predetermined magnitude, to free the weight means for inward movement. 12. A wind turbine rotor according to any of claims 6-11, comprising a drag brake of the type described, carried by each blade. 13. A wind turbine rotor according to any of claims 6-11, wherein said rotor hub has a central portion with no twist, and as the blade extends outwardly from the central portion of the hub, each blade twists to a maximum plus twist, then to a zero twist and then to a minus twist, and wherein the outer end section of each blade has a minus twist. 14. A wind turbine rotor according to any of claims 6-11, wherein the outer end sections of the blades are constructed from a lighter material than the remainder of the rotor, and said outer end sections are both thinner and narrower than the remainder of the rotor. 15. A wind turbine rotor according to claim 6, comprising linkage means housed within the main portion of the outer end section of the rotor, said linkage means having an outer end which is connected to the trailing edge portion at a location offset from the location of hinge connection of the trailing edge portion to the main portion, said linkage means being movable outwardly during deployment of the trailing edge portion to function as a drag brake, said linkage means serving to position the trailing edge portion. 16. A wind turbine rotor according to claim 6, comprising a fixed position tip end portion radially outwardly of the trailing edge portion. 17. A wind turbine rotor according to claim 16, wherein the tip end portion decreases in thickness as it extends radially outwardly, said tip end portion having an aerodynamic cross-sectional shape which progressively decreases in size, and having a leading edge which progressively sweeps rearwardly, and a relatively flat back surface. 18. A wind turbine rotor according to claim 15, comprising a fixed position tip end portion radially outwardly of the trailing edge portion. 19. A wind turbine rotor according to claim 18, wherein the tip end portion decreases in thickness as it extends radially outwardly, said tip end portion having an aerodynamic cross-sectional shape which progressively decreases in size, and having a leading edge which progressively sweeps rearwardly, and a relatively flat back surface.