VI. Answer the following questions:

1. What is a motor?

2. What machine reconverts electrical energy into mechanical energy?

3. Where are motors used?

4. In what household appliances are the motors used?

5. How are the motors classified?

6. What are the most common motors?

Supplementary reading

VII. Look at the plan of a simple two-pole DC electric motor. Try to explain the function of each component.

Inside an Electric Motor

The motor has six parts, as shown in the diagram below:

• Armature or rotor

• Commutator

• Brushes

• Axle

• Field magnet

• DC power supply of some sort

Parts of an electric motor

An electric motor is all about magnets and magnetism: A motor uses magnets to create motion. We know about the fundamental law of all magnets: Opposites attract and likes repel. So if you have two bar magnets with their ends marked "north" and "south," then the north end of one magnet will attract the south end of the other.

On the other hand, the north end of one magnet will repel the north end of the other (and similarly, south will repel south). Inside an electric motor, these attracting and repelling forces create rotational motion.

In the above diagram, you can see two magnets in the motor: The armature (or rotor) is an electromagnet, while the field magnet is a permanent magnet (the field magnet could be an electromagnet as well, but in most small motors it isn't in order to save power).

18 Heating system

Reading

I. Read the following words:

water panel, water tank, through, shower head.

II. Which way does the water flow in this system? Draw arroys to show the direction of the flow.

The main parts of this system are water pipes, a solar water panel, a water tank, an inlet, a valve and a shower head. The tank is above the solar panel.

Cold water enters the system the inlet. It then flows into the tank. From here, the water flows into the solar panel.

The Sun heats the water in the panel. The hot water rises and flows from the panel into the tank. In the tank, hot water stays at the top and cold water sinks to the bottom.

When you open the valve, hot water flows from the tank, through the valve, to the shower head. Here it finally leaves the system.

Vocabulary

III. Remember these words:

pipe, tank, inlet, valve, to sink, to flow, to sink.

IV.Draw the flow chart, putting these boxes into the correct order.

V. Complete the sentences with the correct form of verbs.

1. Water the house through the inlet pipe.

2. Water the solar panel through the outlet pipe.

3. When you heat the water in a tank, the hot water _____

4. When you cool the air in a room, the cool air _______ .

VI. Give the explanation of the system.

Writing

VII. Write an explanation of the system.

19 Electric Shock Safety Electric System

Reading