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Dim Light Shining Bright
12/2/2009
Danielle Gennett, Patrick Smith, Aaron Clevenger, Ryan McCarter
Team 1
Section B1
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1. Project Overview
A generator is a device which converts one form of energy into another, more
useful form. One practical form of generator is a windmill generator. This particular type
of device converts mechanical energy from wind into electrical energy, which can be
used to power electrical devices. The goal of this project was to design and build a
windmill generator capable of powering a small LED light. The design needed to be
relatively simple and capable of being built quickly and from readily available
components.
2. Overview of Wind Energy
Wind energy, in technical terms, is actually a form of kinetic energy. Air
molecules are set in motion by pressure differences (which in turn are caused by different
areas of the planet being heated at different rates by the sun), and this fluid flow turns a
turbine, and the kinetic energy is converted into usable electrical energy (more detail on
this process will be given in a subsequent section) 1 . This is the modern method of
generating electricity via the wind, but in fact, the wind has been used in several ways for
several thousand years. The oldest use of wind power is seen in the sail boat, which has
existed for thousand of years.2 The use of the wind to generate electricity, however, only
occurred much later. The first electricity-generating windmill was built by James Blyth in
Scotland in 1887.3 Though wind power has been used for many other applications, it this
use that is most prevalent today.
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American Wind Energy Association
2
Dodge
3
Nixon
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Recently, interest in wind energy has greatly increased due to several factors. As
concern mounts over climate change, wind energy has garnered significant attention due
to the facts that it is completely renewable, and produces no harmful pollution or
greenhouse gases. Furthermore, greater reliance on wind energy (in addition to other
alternative sources of energy) would allow the United States to reduce its dependence on
foreign oil, benefitting not only the environment, but also national security, as
diminishing oil reservoirs combined with rising demand will increasingly compel the US
to turn to the hostile or unstable countries which control the last remaining oil deposits
large enough to satisfy our demand. 4 Though wind energy alone is insufficient to
accommodate our growing demand for energy, and the current percentage of energy
supplied by wind is small (0.77% in 2007), it is estimated that it could provide up to 20%
of our energy within 20 years.5
3. Generation of Electricity
The process of generating electricity from wind is fairly simple. The distinctive
blades of the windmill are responsible for transmitting rotational kinetic energy to main
mechanism. Fundamentally, all that occurs is that conducting coils surround a magnetic
assembly, which is rotated by the shaft onto which the blades are mounted. The spinning
of the magnets insides the coils creates an electric field which drives a current through
the coils.
4. Design
Fundamentally, this is a simple process. A changing magnetic field produces an
electric field which drives current through the wire. Consequently, there was little
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Klare, p. 20
Environmental and Energy Study Institute
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confusion about precisely needed to be done. After gathering some preliminary
information on the basic principles of a magnetic generator, we examined some
generators built by others. This led us to our first design, similar to our final one with the
exception that we used a magnet which surrounded the copper coils, which spun with the
main axle. After encountering problems with this design (the device would not drive
current, a problem which we attributed either to excessive resistance in one of our
connections, or to a faulty connection), we decided to abandon it in favor of the slightly
more orthodox design in which the magnets spin and the coils remain stationary. This led
us to simple device in which the magnets were connected to the fan axle, and the coils
were wrapped around the outside of the device, around the magnets.
5. Device Description
Our design was very simple, consisting only of the fan and the electrical
components. No support or frame for the generator was constructed. The blades of the
device were made from plastic notebook covers, and bent into a suitable shape. Plexiglass
was used to form a housing for the electrical components. We wound copper coil around
the plexiglass frame, inside of which were the magnets. The magnets were connected to
the fan via a metal rod, and their rotation inside the housing produces an electric field. A
picture of the device is included later in the report.
6. Analysis
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1
1
kg 
m

P = ρ air Av 3 = 1.225 3 (0.0324m 2 ) 8.8  = 13.5238W
2
2
m 
s

TheoreticalPower = 7.5W
ActualPower = Amps • Volts = (0.5 A)(2V ) = 1W
Efficiency =
ActualPower
1W
• 100% =
• 100% = 13.3%
TheoreticalPower
7.5W
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7. Conclusion
In conclusion, the device which we ultimately presented worked reasonably well.
In hindsight, our first design was perhaps slightly more complex, and the time we spent
working on it could have been better spent working on the second design, which would
have allowed us to finish in a more leisurely manner, and possibly to have improved the
performance of our final device. The arrangement in which the magnets spin is a bit
easier to build than one in which the coils spin, and this could have been useful to us at
the beginning of the project.
8. Costs
Plexi-glass = $1
Coils = $10
Magnets = $5
Brass Rod = $3
Plastic Blades = $2
All other minor parts = Free
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Works Cited
Klare, Michael. Blood and Oil. New York: Henry Holt and Company, LLC, 2004. Print.
American Wind Energy Association. December 1, 2009.Web.
<http://www.awea.org/faq/wwt_basics.html>
Dodge, Darrell. Illustrated History of Wind Power Development. "Early History Through
1875." December 1, 2009. Web. <http://www.telosnet.com/wind/early.html>
Environmental and Energy Study Institute. December 1, 2009. Web.
<http://www.eesi.org/wind>
Nixon, Niki. The Guardian. "Timeline: The History of Wind Power." December 1, 2009.
Web. <http://www.guardian.co.uk/environment/2008/oct/17/wind-power-renewableenergy>
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