XII. Put the verbs in brackets into the correct tense and voice.

1. The fission heat (to use) to generate steam, which (to drive) a turbine generator.

2. The world power capacity (to double) about per decade.

3. In order to meet demands for power during the day, utilities (to turn) to other forms of hydroelectric systems.

4. The cooling water (to draw) from a source and (to pass) through the condenser.

5. Much attention (to pay) at present to the development of international scientific contacts.

6. It is evident that electricity (to be) the energy of not-too-distant future.

7. Our power stations (to connect) by high voltage transmission lines into several networks.

8. Cars (to power) by electric batteries in five years’ time and they (not to power) by atomic power in 100 years’ time.

9. It (to announce) that the cryogenic cable (to invent) in Russia.

10. We read that for the first time electricity (to apply) for industrial use in silver workshops in Paris.

XIII. Find active and passive forms of the verb in text 1 a. Write them out into two columns.

Active Voice	Passive Voice
has been transmitting … …	… was installed …

XIV. Read text 1 b. Find the answers in text 1 b to the following questions:

1. When was the early generator discovered?

2. How did the generator look like?

3. To what did the production of practical electromagnets lead?

4. What types of dynamos are known to you?

5. How do they differ from each other?

6. What are the major parts of generators and alternators?

7. Why do the rotors in large machines rotate at a high speed?

Text 1 b. Generators

Within a year of Michael Faraday’s discovery of electromagnetic induction (1831), a small hand generator was demonstrated in Paris, and by 1850 generators were being manufactured in several countries. These early generators were little more than assemblies of coils and permanent magnets that could be maintained in relative motion. Further developments of significance did not appear until the experimental work of William Sturgeon of England and of Joseph Henry and Thomas Davenport of the United States led to the manufacture of practical electromagnets. This technological advance contributed much to the development of practical electrical machines.

The dynamo-electric machines turn mechanical energy directly into electrical energy with a loss of only a few percent. There are two types of dynamos, namely, the generator and the alternator. The former supplies direct current (d. c.) which is similar to the current from a battery and the latter, as its name implies provides alternating current (a. c.).

To generate electricity both of them must be continuously provided with energy from some outside source of mechanical energy such as steam engines, steam turbines or water turbines, for instance.

Both generators and alternators consist of the following principle parts: an armature and an electromagnet. The electromagnet of a d. c. generator is usually called a stator for it is in static condition while the armature (the rotor) is rotating. Alternators may be divided into two types: (1) alternators that have a stationary armature and a rotating electro-magnet; (2) alternators whose armature serves as a rotor but this is seldom done. In order to get a strong electromotive force (e. m. f.), the rotors in large machines rotate at a speed of thousands of revolutions per minute. The faster they rotate, the greater the output voltage the machine will produce.

In order to produce electricity under the most economical conditions, the generators must be as large as possible. In addition to it, they should be kept as fully loaded as possible all the time.