A driven implement 28 may thus be selected of a sufficient size to use all of the power generated by the wind turbine 10 rather than be selected undersized, as is often done to prevent stalling of the wind turbine at low rotational speeds or in a low wind velocity. 10, a relative wind current R is the approximate resultant of the free-stream wind flow W and the tip speed of the turbine rotor T (which is the same as the blade form tangential velocity). This characteristic limits the rotational velocity of the shaft to which the blades are affixed, and it may require a transmission to obtain the shaft speed required for performing the desired work.
The blade 140 is urged into tangential position, i.e., a position in which the chord line CL of the blade form 140 is generally parallel with a tangent to its orbit 138 as defined by rotor 136, by a pair of springs 146 which cooperate with the torque sensitive control. The maximum angle θ through which the blade may pivot is limited by engagement of a second contact surface 171 on each weight 147 and 148, which engages a second frame element 170. A maximum pivotal angle θ through which the blade 140 may pivot, may be selected to provide for optimum performance, and is preferably limited to 30° on either side of a tangent with the blade orbit 138. The maximum pivotal movements of the blade 140 on either side of its tangential position need not be equal, as application of the turbine may require. These difficulties arise not only from the type and height of a structure necessary to position the blades in an adequate wind flow, but also from the high centrifugal forces to which the rotating blades are subjected.
A blade 140 is shown pivotally mounted to an end of the rotor 136, pivotable about axis P longitudinally through a forward portion of the blade 140, which is concentric with a hinge pin (not shown) on which it is mounted. At this point, the centrifugal force is sufficient to maintain the shoulders 65 and 66 of the forward and rearward weights 47 and 48 against the inner surfaces 67 and 68 of the end cap 39. This position of the weights 47 and 48 restricts movement of the hinge pin 42 through the proximal positioning of the fingers 63 and 64 with the raised portion 60 of the collar 51 to hold the blade form in substantially tangential position with its orbit. The blade form 40 is designed and mounted so that the longitudinal axis extending through its center of mass is coincidental with the pivotal axis of the blade form 40, or in other words, the blade 40 is positioned so its center of mass is along the vertical axis of the hinge pin 42 on which it pivots.
The efficient operation of this turbine in low to very high wind velocities permits a user to take advantage of most of the usable annual wind spectrum of a typical installation site, where 90% of the annually available wind energy is found in wind currents between 10 and 40 miles per hour, half of this energy being available in winds of less than 20 miles per hour. Where a blade form 40b is in a 45° position of its orbit, the wind flow W exerts a force against the outer side of the blade to pivotally displace the blade form 40b through an angle θb directed outwardly of its tangent position. Fb through Fd and Ff through Fg, have a component of force acting in the direction of rotation of the turbine, as is shown by their inclination toward the direction of rotation. The angle θb is determined by a balance of the force of the wind and of the spring 146 (of FIG.
Dolor De Espalda
Increasing angular displacement of a blade 140 moves a spring 146 from its unstressed length to increase the force it applies. Since each side of the blade form 40e is exposed equally to the wind current W, the blade form 40e will maintain a tangential position as urged by the springs 146 (of FIG. The resilient material would also allow for a very slight pivotal movement the blade form 40 when it is being firmly held at high speeds of the turbine 10. The tangential position of the blade form 40 as determined by the torque sensitive control 44 may be such that the chord line of the blade form 40 is skewed a few degrees from the tangent of the orbit, for beneficial performance characteristics. They therefore have tip speed ratios in excess of one, and often in the range of four to six.
- Sus semillas son venenosas si se ingieren
- Ease of deployment
- Quality and Safety Monitoring
- Los animales también lloran
- Sensors and signaling means
- Puede desarrollarse súbitamente, en semanas o meses
- Lesiones o dolor en la rótula
- Fomentar la paciencia
A weight 93 and spring 94, similar to either of those previously described in FIG. This type of control has been used to provide for self-starting the turbine, as well as maximizing its efficiency at a specific rotational speed and to limit the maximum rotational speed of the turbine by angular positioning of the blades, as is described in the U.S. 14) acting on the blade 40b, as described supra.