|
Variable Speed Wind Turbine
A variable speed wind turbine is one which is specifically designed to operate over a wide range of rotor speeds. It is in direct contrast to fixed speed wind turbine where the rotor speed is approximately constant. The reason to vary the rotor speed is to capture the maximum aerodynamic power in the wind, as the wind speed varies. The aerodynamic efficiency, or coefficient of power, C_p for a fixed blade pitch angle is obtained by operating the wind turbine at the optimal tip-speed ratio as shown in the following graph. Tip-speed ratio is given by the following expression, \lambda = \frac where \omega is the rotor speed (in radians per second), R is the radius of the rotor, and v is the wind speed. As the wind speed varies, the rotor speed must be varied to maintain peak efficiency. Background Before the need to connect wind turbines to the grid, turbines were fixed-speed. This was not a problem because turbines did not have to be synchronized with the frequency of the g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fixed Speed Wind Turbine
Fixed may refer to: * Fixed (EP), ''Fixed'' (EP), EP by Nine Inch Nails * ''Fixed'', an upcoming 2D adult animated film directed by Genndy Tartakovsky * Fixed (typeface), a collection of monospace bitmap fonts that is distributed with the X Window System * Fixed, subjected to neutering * Fixed point (mathematics), a point that is mapped to itself by the function * Fixed line telephone, landline See also * * * Fix (other) * Fixer (other) * Fixing (other) * Fixture (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stall Regulated Variable Speed Wind Turbine TRS2
Stall may refer to: Enclosures * Animal stall, an enclosure for an animal * Restroom stall, an enclosure providing privacy to the user of a single toilet in a public restroom * Market stall, a makeshift or mobile structures for selling market goods or serving food * Choir stall, seating in a church for the choir * Stalls (theatre), the ground floor seats in a theatre/cinema (closer to or directly in front of the stage) Science and computing * Stall (engine), the unexpected or unwanted stopping of an engine * Stall (fluid dynamics), the fairly sudden loss of effectiveness of an aerodynamic surface * Compressor stall, the sudden loss of compression in a jet engine * Pipeline stall, in computing Places * Stall, Austria, a town in the district of Spittal an der Drau in Carinthia People * Sylvanus Stall (1847–1915), American pastor Art and entertainment *The Stall (Seinfeld) "The Stall" is the 76th episode of the NBC sitcom '' Seinfeld''. It is the 12th episode of the fifth seaso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fully Rated Converter Generator
Fully () is a municipality in the district of Martigny in the canton of Valais in Switzerland. History Fully is first mentioned in the 11th Century as ''Fuliacum''. Geography Fully has an area, , of . Of this area, 30.5% is used for agricultural purposes, while 27.7% is forested. Of the rest of the land, 5.7% is settled (buildings or roads) and 36.2% is unproductive land. It is on the right bank of the river Rhône and is well known for its wines. Fully is just the administrative name of a group of several villages of Vers-l'Eglise (sometimes called Fully), Branson, Châtaignier and Randonnaz along with a number of hamlets. The natural reserve of Les Follatères (shared between Fully and Dorénaz), located on the south facing slopes above the Rhône elbow, has a variety of animal and plant species normally uncommon in Switzerland. Fully-suisse.jpg, Fully at the foot of the Grand Chavalard Colourful lizard - panoramio.jpg, Green lizard Cactuses.jpg, Cactuses (Opuntia) Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doubly Fed Electric Machine
Doubly-fed electric machines also slip-ring generators are electric motors or electric generators, where both the field magnet windings and armature windings are separately connected to equipment outside the machine. By feeding adjustable frequency AC power to the field windings, the magnetic field can be made to rotate, allowing variation in motor or generator speed. This is useful, for instance, for generators used in wind turbines. DFIG-based wind turbines, because of their flexibility and ability to control active and reactive power, are almost the most interesting wind turbine technology. Introduction Doubly fed electrical generators are similar to AC electrical generators, but have additional features which allow them to run at speeds slightly above or below their natural synchronous speed. This is useful for large variable speed wind turbines, because wind speed can change suddenly. When a gust of wind hits a wind turbine, the blades try to spee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pitch Regulated Variable Speed Wind Turbine TRS3
Pitch may refer to: Acoustic frequency * Pitch (music), the perceived frequency of sound including "definite pitch" and "indefinite pitch" ** Absolute pitch or "perfect pitch" ** Pitch class, a set of all pitches that are a whole number of octaves apart ** Relative pitch, the ability to identify a given musical interval between two notes * Pitch accent, a form of accentuation in speech Business * Sales pitch, a line of talk that attempts to persuade someone or something ** Pitch (filmmaking), a proposal for a film ** Elevator pitch, a very short sales presentation, allegedly short enough to be made during an elevator ride Measurement Movement about the transverse axis * Pitch angle (or pitch rotation), one of the angular degrees of freedom of any stiff body (for example a vehicle), describing rotation about the side-to-side axis ** Pitch (aviation), one of the aircraft principal axes of rotation (nose-up or nose-down angle measured from horizontal axis) ** Pitch (ship motion), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stall Regulated Variable Speed Wind Turbine TRS
Stall may refer to: Enclosures * Animal stall, an enclosure for an animal * Restroom stall, an enclosure providing privacy to the user of a single toilet in a public restroom * Market stall, a makeshift or mobile structures for selling market goods or serving food * Choir stall, seating in a church for the choir * Stalls (theatre), the ground floor seats in a theatre/cinema (closer to or directly in front of the stage) Science and computing * Stall (engine), the unexpected or unwanted stopping of an engine * Stall (fluid dynamics), the fairly sudden loss of effectiveness of an aerodynamic surface * Compressor stall, the sudden loss of compression in a jet engine * Pipeline stall, in computing Places * Stall, Austria, a town in the district of Spittal an der Drau in Carinthia People * Sylvanus Stall (1847–1915), American pastor Art and entertainment *The Stall (Seinfeld) "The Stall" is the 76th episode of the NBC sitcom '' Seinfeld''. It is the 12th episode of the fifth seaso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stall (flight)
In fluid dynamics, a stall is a reduction in the lift coefficient generated by a foil as angle of attack increases.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', p. 486. Aviation Supplies & Academics, 1997. This occurs when the critical angle of attack of the foil is exceeded. The critical angle of attack is typically about 15°, but it may vary significantly depending on the fluid, foil, and Reynolds number. Stalls in fixed-wing flight are often experienced as a sudden reduction in lift as the pilot increases the wing's angle of attack and exceeds its critical angle of attack (which may be due to slowing down below stall speed in level flight). A stall does not mean that the engine(s) have stopped working, or that the aircraft has stopped moving—the effect is the same even in an unpowered glider aircraft. Vectored thrust in aircraft is used to maintain altitude or controlled flight with wings stalled by replacing lost wing lift with engine or propeller t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angle Of Attack
In fluid dynamics, angle of attack (AOA, α, or \alpha) is the angle between a reference line on a body (often the chord line of an airfoil) and the vector representing the relative motion between the body and the fluid through which it is moving. Angle of attack is the angle between the body's reference line and the oncoming flow. This article focuses on the most common application, the angle of attack of a wing or airfoil moving through air. In aerodynamics, angle of attack specifies the angle between the chord line of the wing of a fixed-wing aircraft and the vector representing the relative motion between the aircraft and the atmosphere. Since a wing can have twist, a chord line of the whole wing may not be definable, so an alternate reference line is simply defined. Often, the chord line of the root of the wing is chosen as the reference line. Another choice is to use a horizontal line on the fuselage as the reference line (and also as the longitudinal axis). Some aut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stall Regulated Variable Speed Wind Turbine TRS1
Stall may refer to: Enclosures * Animal stall, an enclosure for an animal * Restroom stall, an enclosure providing privacy to the user of a single toilet in a public restroom * Market stall, a makeshift or mobile structures for selling market goods or serving food * Choir stall, seating in a church for the choir * Stalls (theatre), the ground floor seats in a theatre/cinema (closer to or directly in front of the stage) Science and computing * Stall (engine), the unexpected or unwanted stopping of an engine * Stall (fluid dynamics), the fairly sudden loss of effectiveness of an aerodynamic surface * Compressor stall, the sudden loss of compression in a jet engine * Pipeline stall, in computing Places * Stall, Austria, a town in the district of Spittal an der Drau in Carinthia People * Sylvanus Stall (1847–1915), American pastor Art and entertainment *The Stall (Seinfeld) "The Stall" is the 76th episode of the NBC sitcom '' Seinfeld''. It is the 12th episode of the fifth seaso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tip-speed Ratio
The tip-speed ratio, λ, or TSR for wind turbines is the ratio between the tangential speed of the tip of a blade and the actual speed of the wind, v. The tip-speed ratio is related to efficiency, with the optimum varying with blade design. Higher tip speeds result in higher noise levels and require stronger blades due to larger centrifugal forces. :: \lambda = \frac The tip speed of the blade can be calculated as \omega times R, where \omega is the rotational speed of the rotor in radians/second, and R is the rotor radius in metres. Therefore, we can also write: :: \lambda = \frac where v is the wind speed in metres/second at the height of the blade hub. Cp–λ curves The power coefficient, C_p is a quantity that expresses what fraction of the power in the wind is being extracted by the wind turbine. It is generally assumed to be a function of both tip-speed ratio and pitch angle. Below is a plot of the variation of the power coefficient with variations in the tip-speed ratio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apparent Speed Seen By Rotor Blade (or ostensible authority) relates to the doctrines of the law of agency.
{{disambiguation ...
Apparent may refer to: *Apparent magnitude, a measure of brightness of a celestial body as seen by an observer on Earth *Apparent places, the actual coordinates of stars as seen from Earth *Heir apparent, a person who is first in line of succession *Apparent death, an antipredator behavior known as playing dead *Apparent wind, a wind experienced by a moving object *Eire Apparent, a band from Northern Ireland *Apparent authority In the United States, the United Kingdom, Australia, Canada and South Africa, apparent authority (also called "ostensible authority") relates to the doctrines of the law of agency. It is relevant particularly in corporate law and constitutional law ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Stall (flight)")
