VI. Match components 1-8 with their functions a-h with the help of this simplified diagram of a wind turbine.

A	B
1 hub	a transfers power to the generator
2 blades	b links the blades to the low speed shaft
3 gear transmission	c contains the main components
4 high-speed shaft	d stops the turbine
5 generator	e capture the wind energy
6 housing (nacelle)	f increases the speed of the shaft
7 brake	g relays power to the gear transmission
8 low-speed shaft	h produces electricity

VII. Read the web page and answer the questions below.

TECHNO CHANNEL: the TV channel for people who love technology

Techno Channel interviewed the wind turbine expert, Dr Roger Jones.

How does the wind turbine work?

The wind blows on the blades and make them rotate. This causes the shaft to rotate at a speed of about 30-60 rpm.

But isn’t that too slow? The shaft in a generator must rotate at about 1200-1400 rpm.

That’s right. There are two shafts. There’s a low-speed shaft and a high-speed shaft. The low-speed one is attached to a large gear. The high-speed one is attached to a small gear. The large gear makes the small gear turn and the small gear makes the high-speed shaft rotate. This shaft rotates at 1200-1400 rpm.

Ah, I see. And it drives the generator at this speed?

That’s right. And then the generator produces AC electricity.

What happens if the wind is too strong?

The anemometer measures the speed of the wind. It sends this data to the controller. (The controller is a small computer.) If the speed of the wind is more than about 90 km/h, the controller automatically switches off the wind turbine. This prevents from damaging the turbine.

1. Which part makes the low-speed shaft turn?

2. What are the two main functions of the controller?

3. Which part transmits rotation to the generator?

Speaking

Rotors and turbines

VIII Try this quiz. What do you know about wind turbines?

1. How tall is the tower of the world’s tallest wind turbine? a) about 100 m b)about 180 m c) about 200 m 2. How high is the world’s highest turbine? a) about 1800 m b)about 2300 m c) about 2600 m 3. What’s the minimum wind speed for a large wind turbine? a) about 15 km/h b)about 20 km/h c) about 25 km/h 4. What’s the maximum wind speed for a large wind turbine? a) about 45 km/h b) about 70 km/h c) about 90 km/h

Electric motors

Reading

I. Read the following words:

mechanical, engine, utilize, reconvert, household, desirable, interchangeability, standardized, synchronous, uniformity, nevertheless.
Date: 2015-12-11; view: 2852

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II. Read and translate the text. | V. Form sentences combining suitable parts of the sentences given in columns I and II.

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