Likewise, it will be seen that movement of spools 75 and 80 of control valves 55 and 60 in the opposite direction (to the left) causes an opposite pressurization and drain of blade actuators 35 and 40 thereby causing counterclockwise movement of platform 20 and blade 10. © 1996-2015 National Geographic Society, © 2015- Researchers are working on high-frequency noise generators that would be audible to bats and drive them away from wind turbines, ultraviolet lights to illuminate towers and repel bats, and behavioral studies that would help the industry fine-tune when it should feather turbines. ... feathering pitch wing Prior art date 1982-06-22 Application number KR1019830002805A Other languages Korean (ko) Other versions KR840005192A (en Inventor 이반 하너 커미트 피터 패트릭 존 프랭클린 보셀러 케네스 Original Assignee 멜빈 피. type installation fitted with a smaller turbine of earlier design. Thus, where the terms "controllers" or "flow controllers" have been used, such terms refer not only to constant volume controllers such as those described, but also to flow resistances which may be placed in selective fluid communication with the actuator to achieve feathering at a higher initial rate and a lower (dimished) subsequent rate. The cut-in and cut-out speeds are the operating limits of the turbine. Actuator control valves 55 and 60 include inner, connected spools 75 and 80, respectively, and valves 65 and 70 include inner, connected spools 85 and 90, it being readily apparent that the four actuator control valves may be substantially identical. For example, a propeller with a 12" pitch when rotated once, will propel the vessel 12" ahead. Such movement of actuators 35 and 40 cause a clockwise movement of platform 20 and therefore, blade 10. The story is part of a special series that explores energy issues. ASSIGNMENT OF ASSIGNORS INTEREST. A suitable pitch controller is disclosed and claimed in U.S. Pat. with a narrower airfoil at the tip. since the blade pitch angle is controlled passively by wind and inertia some or all of the cost of added blade complexity. In the preferred embodiment, the feather actuator is an hyudraulic actuator and the control means comprise parallel flow controllers in a line through which hydraulic fluid is drained from the actuator. Blade pitch control is preferred over rotor brakes, as brakes are subject to failure or overload by the wind force on the turbine. To achieve such feathering, the pitch angle of the blades is adjusted to approximately 90° whereupon wind flow over the blades fails to produce any torque which would otherwise cause rotation of the blades and therefore, rotation of the generator rotor. moved through conceptual and analysis stages and is ready for Component Although this was not a hurricane, it does demonstrate the shutdown process. A new wind turbine design has moved through conceptual and analysis stages and is ready for Component Development under DOE Technical Area 2. Our 3 MW turbines range from 3.2 to 3.8 MW power output, and includes the 3.6-137, our highest performing turbine for Class III winds. What sets the Superwind apart from other micro-wind turbines is their patented auto-feathering blade system that prevents damage to the system when wind speeds approach high levels by automatically and individually adjusting blade pitch to the wind force. Since the velocity 1. Flow controllers 330 and 335 (as well as valve 340 discharge to drain line 247). Wind turbines need to protect themselves just as communities do during tropical storms and hurricanes. To limit this speed-up Researchers still aren’t sure what draws bats to wind turbines. to design, fabricate, instrument, and test this turbine mounted above The expected advantage of this However, hydraulics tend to require more power to keep the system at a high pressure, and can leak. two-bladed turbines using a tail. The term has applications in aeronautics, shipping, and other fields. The blade feathering system of claim 1 characterized by said flow controllers being connected in parallel relationship to one another and said pitch rate control valve being serially connected in said one flow controller. In the blade pitch control system of the present invention, such a diminishing feather rate is achieved by draining of the right side of feather actuator 299 at a decreasing rate. To understand what happens, let’s first discuss a wind turbine’s power curve. Fish and Wildlife Service last year. (Photo by Dennis Schroeder / NREL), Project Management Coordination Office Home, Competency Management & Cross-Cutting Activities, Operations, Audit Resolution, & Internal Controls, Weatherization and Intergovernmental Programs Office, on full display at Rhode Island’s Block Island Wind Farm. Control valve 225 is provided with any suitable actuator such as an electromagnetic actuator 250 receiving an input signal thereto from main pitch controller 255. local wind affecting each blade. Such movement of links 200 and 202 moves the spools of control valves 55, 60, 65 and 70 to the right, pressurizing actuators 35, 40, 45 and 50 to move blade 10 in a clockwise direction and blade 15 in a counterclockwise direction thereby increasing the pitch of both blades. a pitch rate control valve operated by said feather actuator and in fluid communication with one of said flow controllers for selectively blocking flow therethrough in response to operation of said feather actuator for carrying out said blade feathering at a diminished rate. There are also overspeed centrifugal devices connected to the pitch cams to cause the blade tips to feather in emergency overspeed conditions so as to stop the rotor. torsion from the trim tab region of the blade. Because the velocity of a propeller blade varies from the hub to the tip, it is of twisted form in order for the thrust to remain approximately constant along the length of the blade; this is called "blade twist". Migratory bats, for some reason, have a lethal attraction to wind turbines. System for bringing the blades of a wind turbine into position. In a blade feathering system for a wind turbine comprising at least one variable pitch blade movable to feathered position and an hydraulic feather actuator adapted to control the feathering of said blade, the improvement characterized by: said feather actuator having a drain line connected thereto for draining hydraulic fluid therefrom; a pair of flow controllers communicating with said drain line for controlling the rate of draining of said feather actuator and therefore, the rate of operation thereof; and. When wind speeds surpass a modern utility-scale turbine’s rated wind speed, the blades begin to feather, or point into the wind to reduce their surface area. It is another object of the present invention to provide such a wind turbine blade feathering system of enhanced reliability.