getting electricity from the wind

8/4/2019 Getting Electricity From the Wind

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TEXT 9 : GETTING ELECTRICITY FROM THE WIND

GETTING STARTED

Look at these pictures.

1. Tell what you can see in picture A.

2. Tell what you can see in picture B.

3. How are both pictures related?

4. Do you think the wind is useful to us? List a few ways how the wind canhelp us carry out our daily activities.


By the end of this unit, you should be able to:

i) Read and answer questions on a textii) Draw and label a diagramiii) Write an interviewiv) Listen and complete a text

PICTURE A PICTURE B


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LETS READ

A. Read the passage below and answer the questions that follow.

1 Modern wind generators are very different from the old windmills.They are more like giant propellers with two or three blades, called rotors,

mounted on top of tall towers of steel or concrete. The rotors turn a shaft,which drives an electric generator.

2 The size of the blades and the height of the tower determinehow much electricity the machine can generate. Wind generally getsstronger as you go higher, and the power of the wind you capture dependson the swept area of the blades. Double the length of the blades and thepower increases four-fold. More important still is the speed of the wind if it blows twice as hard, there is eight times as much power to be had.

3 However, wind generators do not need stormy weather. Mostmachines are designed to operate at wind speeds between Force 3 and

Force 10 on the Beaufort scale 13 to 60 mph (21 to 97 km/h). AboveForce 10 the machines will automatically shut down.

4 Most machines are designed to produce much the same powerthroughout their working range, the blades automatically feathering as thewind increases. Therefore, it is better to have a steady output over a widerange of wind speeds than to be able to take advantage of the few reallystrong gusts.

5 Wind generators must point in the right direction, either towardsthe wind or away from the wind. For this reason the rotor is mounted on aturntable and controlled by an electric motor connected to sensors. The

sensors will tell the rotor which way to face.

6 This problem of wind direction can be avoided completely if theblades are mounted vertically rather than horizontally. Then it does notmatter where the wind is blowing.



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7 These vertical machines, called Darreius Turbines, have other advantages.The machinery that converts the power into electricity can be placed onthe ground rather than at the top of a tower. The rotor is, therefore,subjected to less stress than in the horizontal - axis generators. Adisadvantage is that they often need a push to get started, either by handor by an electric motor.

COMPREHENSION CHECK

A. Answer the questions below.

1. Describe how modern wind generators look like?

2. State the function of the rotors.


Adapted from How is it DoneThe Readers DigestAssociation Limited, London 1990


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3. What are the four features that determine the amount of electricity thatgenerators can generate?

i) ii)

iii) iv)

4. What is the function of the sensors in wind generators?

5. Wind generators do not need a stormy weather. Why?

..

6. Is it better for the blade to be mounted vertically than horizontally? Why?

..

.

7. What do you think will happen if the wind generators are not shut down whenthe wind speeds above Force 10?

.

.

8. Do you think it is possible to use wind generators to produce electricity in

Malaysia? Give reasons for your answer.

.

.

B. Based on the text, complete the table below with the differences of theDarreius Turbines and Wind Generators.

Darreius Turbines Wind Generators

1. Blades are mounted on verticalaxis

1. .

2. 2. .

3. 3. .



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WORD POWER

A word sometimes may mean differently in different context.

For example: Concrete definite, positiveConcrete building material made by mixing cement with sand, gravel

and water.

A. These words are found in the text. Find the meaning in context.Choose the best answer.

1. GeneratorsA. Machine for producing electrical energy.B. Machine or apparatus that produces steam, gas, vapour, etc.C. Person who generates or originates.

2. DetermineA. Fix something precisely; decide.B. Find out something that is not known; calculate.C. Decide firmly that something will be done.

3. CaptureA. Take prisoner, seize, obtain by force or trickery.

B. Act of capturing, thing or person captured.C. Absorb.

4. DesignedA. Prepared a design for.B. Intention or purpose.C. Established form of a product.

5. ConvertsA. Gain extra points after scoring a try by kicking a goal.B. Change from one form or use to another.C. Change ones beliefs especially ones religion.

6. StressA. pressure or worry resulting from mental or physical distress.B. Extra force used in speaking a particular word or syllable.C. Force that acts on a thing or between parts of a thing and tends to pull

or twist it out of shape.



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words.

A B1.

a) Fixed on a support or in a frame (Para.1)

2.

b) A metal bar in an engine that causes a part to move(Para.1)

3.

c) Four times the number of (Para.2)

4.

d) Produce(Para.2)

5.

e) Work (Para.3)

6.

f) Fanning (Para.4)

7.

g) Constant (Para.4)

8.

h) Sudden strong wind (Para.4)

9.

i) Flat and level position(Para. 7)

10.

j) Unfavourable condition (Para.7)

LANGUAGE FOCUS

Prepositions

A Preposition is a word that joins a Noun or a Pronoun to another word.

For example: From starting at a particular place, position or conditionYou can see the river fromthe top of the hill.

The sentences in bold contain some wrong prepositions. Write the correctprepositions in the space provided.

1. They are more like giant propellers with two or three blades, called rotors,mounted in top by tall towers of steel or concrete.

..


B. Find the words in the text that has the same meaning inColumn B. Complete Column A with the mostappropriatewords.


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2. Wind generally gets stronger as you go higher, and the power of the wind youcapture depends for the swept area of the blades.

.

3. More important is the speed of the wind, by the power that can be extractedgoes up as the wind speeds up.

..

4. Most machines are designed to operate along wind speeds by Force 3 andForce 10 in the Beaufort Scale.

..

5. It is better to have a steady output before a wide range of wind speeds thanto be able to take advantage of the few really strong gusts.

6. Wind generators must point out the right direction; either directly towards thewind or directly after it.

..

7. For this reason the rotor is mounted under a turntable and controlled over anelectric motor connected by sensors which tell it which way to face.

8. Then it does not matter where the wind is blowing by.

Article The

The definite article the is used when we speak of a particular person, thing or onealready referred to.

For example : Thebook you want is out of print.

I dislike thefellow.Let us go to theclub



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Look at the text. Identify sentences from the text that contain definite articlesthe. Write out the sentences.

1.

2.

3.

4.

5. ...

6. ..

7. ..

8. ..

LETS WRITE

You are a reporter from The Star. Conduct an interview with an Electrical Engineerfrom the Department of Science and Technology on How Solar Energy is GeneratedTo ProduceElectricity. Write out the interview.

High temperature collector called solar furnaces generatelarge amounts of electricity.

Many flat or slightly curved mirrors focus the suns rays on atarget such as a piece of metal.

Fluid such as water is pumped inside the target where it is

heated. The steam or gas that results from heating the fluid carries heat

energy to turbines that generate electricity.



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LETS EXPLORE

B Draw a picture of a wind generator and label the following:

1) fan 2) shaft 3) generator4) blades 5) tall tower


How Turbines and Generators Create Electricity

Turbines consist of a series of (1) __________ one in (2) __________, of the

other, which drive a (3) __________ when they (4) __________. The shaft in turn

drives a (5) _________. Alternate fans always remain (6) __________. The

position and (7) _________ of these fans direct the pressurized (8) _________, or

(9) _________ onto the rotating fans with the maximum possible force. At the end of

the shaft is a large (10) _________, which is surrounded by a coil of wire, inside the

generator. As the magnetic core rotates, it causes an electric current to flow through

the wire coil.

A Listen to a tape on How Turbines andGenerators Create Electricity. As youlisten, complete the text below. (See tapescript at theback).


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TAPESCRIPT

Listen to the text carefully. As you listen complete the text below.

How Turbines and Generators Create Electricity

Turbines consist of a series of fans, one in front of

the other, which drive a shaft when they rotate. The

shaft in turn drives a generator. Alternate fans always

remain stationary. The position and shape of these

fans direct the pressurized steam, or water onto the

rotating fans with the maximum possible force. At the

end of the shaft is a large magnet, which is surrounded

by a coil of wire, inside the generator. As the magnetic

core rotates, it causes an electric current to flow through

the wire coil.



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UNIT 1 GETTING ELECTRICITY FROM THE WIND

ANSWERS

COMPREHENSION CHECK

A. Comprehension questions:

1. They are more like giant propellers with two or three blades, mounted on topof tall towers of steel or concrete.

2. The rotors turn a shaft, which drives an electric generator.

3. I) The size of the blades ii) The height of the toweriii) The speed of the wind (v) The power of the wind

4. The sensors tell the rotors which way to face the wind.

5. Most machines are designed to operate at wind speeds.

6. Yes - the problem of wind direction can be avoided.

7. - Too much electricity is produced- The machines will become damaged

* Any other possible answers

8. Yes it can be built along the seaside where the wind is constant savesmoney using the renewable resources.

No - too expensive to build generators- no constant supply of wind- weather is not reliable

*Any other possible answers

B.

Darreius Turbines Wind Generators

1. Blades are mounted on vertical axis 1. Blades are mounted on horizontal axis

2. The generating machine can be placedon the ground.

2. The generator is placed on a top of atower.

3. The rotor is subjected to less stress. 3. The rotor is subjected to more stress



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WORD POWER

A.1. A 2. B 3. C4. B 5. B 6. C

B.1. mounted2. shaft3. four-fold4. generate5. work6. feathering7. steady8. gust9. horizontal10. disadvantage

LANGUAGE FOCUS

A. Prepositions1. on, of2. on3. for4. at, between, on5. over6. in, from7. on, over, to8. from

Article The

1. The size of the blades and the height of the tower determine how muchelectricity the machine can generate.

2. ..the power of the wind you capture depends on the swept area of theblades.

3. Double the length of the blades and the power increases four-fold.

4. .. is the speed of the wind-.. much power to be had.

5. .. the blades automatically feathering as the wind increases.

6. For this reason the rotor is mounted on a turntable and controlled by anelectric motor connected to sensors.

7. The sensors will tell the rotor which way to face.

8. Then it does not matter where the wind is blowing.


getting electricity from the wind

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