Wind turbine corr

The wind turbine.
Page 1
How stuff works
Engineering Sciences
and Technology
INTRODUCTION - PART ONE
1/ Watch the first part of the video twice (“introduction - part one.avi”). Fill in the blanks while
and after listening. (one blank = one word)
You may have been driving through the countryside and suddenly come up on something
like a tall tower with big triple blade at the top rotating and you wonder what it is: it is a wind
turbine.
The purpose of this is to generate electricity and they tend to be extremely big so you see
them in the distance, but when you get close to them, they are very big.
The other problem with them is they do produce pollution, so be careful, but it's
sound pollution. Many people find it very disturbing the noise these things make as these
blades woosh past you. So be aware of that.
All it is, is basically a tall, concrete, stress concrete tower and on top of it, is a
generator, an electric generator. The electric generator is very simple, it can be
mounted right on the top of here and it is driven directly by the fan blade.
2/ What are the main components of a wind turbine ?
A wind turbine is composed of: A tall concrete tower with an electric generator mounted on top
which is driven by a big triple fan blade
3/ Point them out on the picture below.
Triple fan blade
Electric Generator
Tall Concrete Tower

The wind turbine.
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4/ What is the goal of the wind turbine?
The goal of the wind turbine is to generate clean and renewable electricity from wind power.
5/ What kind of environmental impact does the system create?
The system does create sound pollution from the rotating blades
6/ How does the electric generator move?
The wind drives the triple blade fan and puts it in rotation
INTRODUCTION - PART TWO
1/ Watch the second part of the video twice (“introduction - part two.avi”). Fill in the blanks
while and after listening. (one blank = one word)
Now obviously, there is at this point what we call a gearbox because, obviously, the blade
goes round quite slowly and if it went round that slowly, the generator wouldn't generate
much electricity. But there is a gear box to speed up the rotation in the generator so even though
this goes round quite slowly, the generator is at its full capacity and will generate electricity.
This electricity then is fed down the tower and out to the electricity grid where it can
supplement electricity produced in other ways. It is interesting to note that you can not just put
them anywhere.
Obviously, the energy which is used is wind energy and the air is moving. And as the air moves
past, the energy is removed from the air. So, you can't put a lot of them very close to each
other because one will affect the work of the other.
And in fact, that's why you see they're fairly well spread out because they have to have their
own area of air to work in. So that's a wind turbine; how it works and how it is set up .
If you see one, just think, this will be producing energy for the foreseeable future.
2/ The blade rotates?
 slowly  at a medium speed  fast
3/ The electric generator rotates?
 slowly  at a medium speed  fast

The wind turbine.
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4/ What is the purpose of the gear box?
It matches the fan rotation speed to the one required by the asynchronous motor to generate electricity
5/ Here is the internal block diagram of the wind turbine.
▪ Fill in the two missing parts in the diagram.
▪ Fill in the three missing links (these links are energy…).
6/ Why can't we implement two wind turbines very close to one another?
When harvested by the blade fan, the air loses its potential energy and
therefore doesn’t have the power to drive infinite number of blade fans. That’s
why it’s required for wind turbines to be spread out.
DECONSTRUCTED - PART ONE
1/ Watch the first part of the video twice (“Deconstructed - part one.avi”). Fill in the blanks
while and after listening. (one blank = one word)
Wind turbine blades are aerodynamically designed to catch the maximum amount of wind energy
to make them rotate. Inside the turbine, an electromagnetic system transform that
Rotational movement into electricity that is stored in a battery. The stronger the wind, the
faster the blades rotate, the more power generated. Getting the blades moving is the first step
and to do that, of course, requires a strong, steady, wind.
The carbon fiber blades are aerodynamic to fully exploit wind power. One surface is rounded,
the other relatively flat. Wind flowing over the rounded sides speeds up and creates a low
pressure pocket that sucks the blades sideways, what's known as lift . Now that lift sets the
blades in motion, let's see how this rotation can be turned into wattage to power the fridge or
stove.
:Electric
Generator
: Blade
Fan
Wind Energy
Rotational
mechanic energy
(high speed)
Electric Energy
(~AC)

The wind turbine.
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2/ Why are blades made in carbon fiber?
Carbon fiber is a strong material with a high strength to weigh ratio, which means it can
sustain a lot a mechanical constraint while remaining light.
3/ Give an example of another system which uses
lift process.
This effect is also exploited in aircraft
and race-cars
4/ Compare the wind turbine from video n°1
(Introduction) and the one from video n°2 (Deconstructed).
Video n°1 (Introduction)
Video n°2 (Deconstructed)
Tall
Made out of concrete
Rotates slowly
Connected to the electric grid
Gear box
Small
On a metal tripod
Rotates fast
Connected to a battery
Direct drive
DECONSTRUCTED - PART TWO
1/ Watch the second part of the video twice (“Deconstructed - part two.avi”). Fill in the blanks
while and after listening. (one blank = one word)
When the blades turn, they spin a shaft connected to a rotor inside a generator.
Twelve small magnets fixed around the rotor turn inside the stator made of coils of
copper wire. These magnets are an alloy of neodymium, iron and boron. They are small
but powerful . In fact, they're among the most powerful magnets on earth. The
turbine needs their incredible strength
electricity.
to turn the blades' rotational energy into
When the magnets rotate inside the stator, they create a moving magnetic field and
the laws of electromagnetism dictate what follows : electrons in the copper coil also start
moving. The movement of these electrons produces what's called an alternating current,
the kind that comes out of conventional wall outlets.
2/ What the function of the shaft?
It drives the rotor from the rotation movement of the blades

3/ Explain how generator creates alternating current.
The wind turbine.
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The rotation of magnets (and therefore their respective magnetic field) inside a set of copper
coil sets the electrons in motion which generates an alternative current
4/ At home, where can you find alternating current?
Out of a conventional wall outlet.
DECONSTRUCTED - PART THREE
1/ Watch the third part of the video twice (“Deconstructed - part three.avi”). Fill in the blanks
while and after listening. (one blank = one word)
Alternative Current is easy to produce and to distribute but impossible to store in a
battery . It needs to be transformed into a direct current in order to be contained.
This electronic circuit inside the turbine does the job. With winds of twenty-height
miles per hour , this particular turbine can produce four hundreds
enough to light up four one hundred watt light bulbs.
watts of power,
It doesn't seem like much. But the wattage can be boosted
storing the energy in the battery.
STRUCTURAL DIAGRAM
by accumulating and
1/ Look at the flash document named "How wind power works". From what you can see and
understand, fill in the structural diagram
below.
Rotor (fan)
Nacelle
Shaft
Gearbox
Electric Generator
Tower
Transformer