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Windmill Generator Project

Tyler Bowland

Travis Childress Stephen Fly

Andrew Hinson

November 30, 2009 EGR 152 Section A1 Team 9

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Project Overview

As instructed, our team built the simplest, most efficient windmill able to generate

electricity by using supplies within our predetermined budget. Our goal was to generate

enough voltage and current to power a small, 1.5-watt LED light bulb. We were

successful by building a structure where wind energy caused oppositely charged magnets

to spin rapidly, generating an electric charge transferred to the coated enamel wire

surrounding the magnets. This magnetic field we created rapidly caused a charge to be

pushed along the wire until it reached the wire’s ends, where we soldered the light bulb.

By soldering bulb onto the electromagnetic wire we completed the circuit.

History of Wind Energy

The main factor in producing enough power to illuminate the light bulb is the

speed of the wind and how efficiently we convert it to electricity. This is a challenge man

has attempted to tackle for hundreds of years. Wind energy originated as early as 5000

BC to propel boats along the Nile River, and in 200 BC wind energy was used to pump

water in China. By the 11th century, wind energy was used for various machinery farms.

By 1980, larger windmills were used in Denmark to generate electricity, and in 1940

“Grandpa’s Knob” in Vermont became the largest wind turbine in existence. It could

generate 1.25 megawatts of power using winds up to 30 mph, and it powered a local

utility network during World War II.

(www1.eere.energy.gov/windandhydro/wind_history.html) A wind turbine transforms

kinetic energy of the wind into electrical energy for practical use. For our application, this

practical use is lighting a filament in a bulb. There are two basic designs of wind electric

turbines: the vertical-axis “egg beater” style, and the more common horizontal-axis,

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propeller-style. We chose to model our design after the propeller-style turbine, where

blades convert the wind’s energy into rotational shaft energy. The nacelle is an enclosure

that contains the gearbox and generator, and in our case magnets bounded by electrical

tape. A tower is needed to support the rotor and drive train, and in our case is a wooden

tower with a hole where the shaft can go through. (www.awea.org/faq/wwt_basics.html)

Wind power has an expansive future according to experts. Wind energy has been

the fastest growing source of electricity generation in the world in the 1990s. However,

the majority of this growth has been in Europe, where government policies and high

conventional energy costs favor the use of wind energy. Massive European Union and

local government subsidies have jump started the alternative energy movement. The U.S.

Department of Energy recently announced the Wind Powering America Initiative with

goals to power at least 5% of the nation's electricity with wind by 2020, increase the

number of states with more than 20 megawatts of wind to 16 by 2005 and 24 by 2010,

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and increase federal use of wind energy to 5% by 2010. (www.e-marine-

inc.com/products/wind_generators/wind)

Design & Construction

Regarding our design process, our team chose an idea that would be simple,

efficient, and was non-expensive to make. We researched ideas on how to make our

generator, and decided that a large fan-blade would cause the magnets to rotate the

fastest. We originally wanted to build a structure with a vertical tower, with a rod going

through it that connected to the middle of the fan blade. At the base of each fan blade, we

would have a magnet and magnet inside the metal rod, totaling 6 magnets. Around the

inside magnet we would wrap it with enamel coated wire and attach the light bulb to the

end of the wire. This idea, however, was discarded after future research because the one

magnet wouldn’t be able to create a strong enough magnetic field. We then resorted to a

similar idea but we would put four magnets on the outside, end of the rod. We would

have a negative and positive magnet facing outward, with a box around it wrapped in

thin-coated wire. Attached to the ends of the wire would be the light bulb ends. This idea

would generate enough voltage and current to illuminate the light bulb.

The TTAS (Tyler, Travis, Andrew, Stephen) windmill constructed in this

experiment used a Lasko 20” box fan blade to capture kinetic energy. The blade was

modified and attached to a carbon steel pipe. The fan and steel pipe rotate on a short

4”x4” board counterweighted by four magnets arranged in an attractive order. A plexi-

glass housing closely surrounds the magnets with the enamel coated wire wrapped around

the housing. Approximately 350 feet/turns of coated copper magnet wire was used. This

turned out to be roughly one foot a turn. 250 feet of 30 gauge wire, 100 feet of 26 uge

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wire was wrapped around the housing. This design provides a simple alternating current

(AC) generator creating current when propelled by wind. The current traveling through

the conducting wire illuminates the light bulb with ease. When propelled rapidly the

maximum power input exceeds the capacity of the bulb and destroys the circuit.

Power Generation & Calculations

The alternating current generator, commonly known as the alternator, develops

power by changing the polarity of current repeatedly through a conductor. When the

positively charged magnet passes by the conductor, electrons travel up the wire and

create a positive charge. When the negatively charged magnet passes the conductor the

electrons travel in the opposite direction and create a negative charge. The faster the

oppositely charged magnets pass by the conductor the more the frequency is increased.

When our generator starts up the light initially blinks. The reason we can see the flashing

of the light is we are not producing a high enough frequency to make the pulses of light

faster than our eyes can perceive. However, when we conducted our final test we

achieved a high enough frequency for our eyes to judge the light was on constantly. This

increased frequency results in greater electromotive force or stronger current through the

conductor.

Our estimated efficiency proved that this project as a whole was not very

efficient. We generated up to 9 Volts and 0.080 Amps in class, but considering the

amount of wind energy produced compared to the electric energy produced, it was not

efficient. Based on the cost of spending $40 and given the large size of the apparatus, and

only generating the same amount of light as a handheld flashlight, this alone says our

project was not very efficient.

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The power (i.e. energy per second) in the wind hitting a wind turbine with a

certain swept area is given by simply inserting the mass per second calculation into the

standard kinetic energy equation given above resulting in the following vital equation:

Power = 0.5 x Swept Area x Air Density x Velocity3

.3914 watts = 0.5 x (pi (.49meters /2)2) x (1.23 kg/m3)x(.15meters/second)3

These equations could be used to calculate output on the specific loop of wire we made. Magnetic Flux = BAcosØ (where B = magnetic field, and A = cross sectional area) Force on a current loop = BIa (where a = bsin(90-Ø))

The following values were measured using a voltmeter while the windmill was propelled by an artificial wind source. Table 1

The following table details the materials used to construct the TTAS windmill.

Table 2

TTAS Windmill Materials & Expenses Material Quantity Cost

20" Box Fan 1 $15.00 Coated Copper Wire 1.5 $8.00

Plexi-Glass 1 $6.00 Carbon Steel Pipe 1 $3.00

TTAS Windmill

Measurements Volts (AC) Current (A) Resistance Ω

Low 3.2 .0018 1777

Medium 3.7 .0030 1233

Fan

Spee

d

High 4.4 .0036 1222

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Ceramic Magnets 2 $3.00 4"x4" Post (Scrap) 1 $2.00

Wood Base (Scrap) 1 $1.00 WD-40 (Shop) 1 $0.00

Electrical Tape (Shop) 1 $0.00 Hot Glue 1 $0.50

Nails 3 $1.50 Total Expenses $38.00 Unused Budget $2.00

Conclusion

In conclusion, our experiment was a great success. We were able to make our

windmill generator in the time frame we allotted for in our Gantt chart. We used a very

simple technique that produced more than enough power to illuminate the light bulb. All

the supplies used fit our budget nicely, and the actual design took very little time. The

main problem we faced was dealing with the wire direction around the plexi-glass box.

Originally we just wrapped the box completely with the wire, not paying attention to how

many layers we were wrapping it with or the direction the wire was being wrapped in.

After the light bulb did not light up, we unwrapped the box completely and rewrapped it.

We made sure to maintain the same direction and not to overlap as much. We learned that

with carefulness and determination, this project was not as difficult as we originally

thought. Positioning the oppositely charged magnets correctly was initially difficult, but

we were able to perform this experiment successfully after minor changes. As a group,

we were able to visually see how electricity works and learn how the wind from a fan is

converted to electricity. The multiple steps of trial and error taught us to plan well, and

have realistic expectations about how long things take. By working together and carefully

tracking what we had done we successfully completed a project we enjoyed working on

and learned about what is required to generate power through non-conventional means.

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