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Build a Model Turbine: Ride
the Wind!TM
education resource site
Savonius
Wind Turbine
These plans are for the construction of a machine called a Savonius wind
turbine. Wind turbines come in two general types, those whose main
turning shaft is horizontal and points into the wind, and those with a
vertical shaft that points up. The Savonius is an example of the vertical
axis type. It consists of two simple scoops that catch the wind and cause
the shaft to turn.
This
type of turbine is simple to build, but is not nearly as efficient as a
well-designed horizontal axis turbine. The Savonius turbine relies solely
on drag to produce the force that turns their shaft. One side of the
turbine catches the moving air more than the other, causing the turbine
to spin. This design does not allow the turbine to spin faster than the
oncoming wind, which makes them a poor choice in areas where winds are
light.
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A Savonius
wind turbine.
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Horizontal
axis turbines are by far the most common kind of wind turbine. They can
be seen at several places across Canada and the United States. They are
also becoming common in Europe and many other countries around the world.
These turbines feature wing-like blades that generate aerodynamic lift as
the wind blows past them, causing the central shaft to turn. To operate
at peak efficiency, this type of turbine must always face directly into
the wind. Many horizontal turbines have a large wind vane that acts like
a sail, helping them to stay pointed in the right direction.
Making
electricity
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A horizontal
axis turbine.
Courtesy Vision Quest Wind Electric.
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We are surrounded by hundreds of appliances that use
electricity to do work. But what is electricity? Basically, electricity
is a flow of electrons in a metal wire, or some other conductor.
Electrons are tiny particles found inside atoms, one of the basic building
blocks of all matter. We call the flow of electrons through any conductor
a "current of electricity."
Each
electron carries a tiny negative charge. When they move through a
conductor, they produce an invisible field of magnetic force, similar to that
found around a magnet. The strength of that field depends on how many
electrons are in motion. You can concentrate this field by winding the
wire in which the electrons move into a tight coil with many turns. This
causes many more electrons to be in motion in a small space, resulting in
a stronger field. If you then place a piece of iron in the middle of the
coil, the electromagnetic field will turn the iron into a powerful
magnet.
While
it is true that electrons moving through a conductor produce a magnetic
field, the reverse is also true. You can make electrons move in a wire by
"pushing" them with a moving magnet. This is in fact how an
electrical generator works. Electrical generators usually contain
powerful magnets that rotate very close to dense coils of insulated wire.
The coils develop a flow of electrons that becomes an electrical current
when the generator is connected to an electric circuit.
You
will be building an electrical generator as part of this project. It uses
moving magnets to create a current of electricity in coils of wire. This
generator is technically called an alternator because the electrons move
back and forth in the wire, rather than flowing in just one direction as
they do from a battery. A meter connected to the wire would show that the
charge of the wire switches or alternates between positive and negative
as the electrons change directions. Such an electrical current is called
alternating current or AC. Household electrical current is alternating
current. Appliances have to be specially designed to use it. The other
type of current is called direct current, because the electrons move in
one direction only. Most battery-powered appliances such as calculators
and portable CD players use direct current.
Click Here to
Download the Construction Plans
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