Electric Generators and Motors

 

1) A device for converting mechanical energy into electric energy is called a generator. The function of a motor is just the reverse, that is, it transforms electric energy into mechanical energy. The enormous energy of steam engines, gas engines, and water turbines can now be transformed into electricity and transmitted many miles.

2) The essential parts of a generator are: a) the magnetic field, which is produced by permanent magnets or electromagnets; b) a moving coil of copper wire, called the armature, wound on a drum.

3) The main difference between a d.c. generator and a. c. generator is that the former has a commutator by means of which the generated electromotive force (EMF) is made continuous, i.e., the commutator mechanically rectifies the alternating electromotive force so that it is always of the same polarity.

4) A d. c. generator as well as a motor of conventional type is made up of the following parts: outer frame, or yoke, pole cores, pole coils, armature core, armature windings, commutator, brushes, and bearings.

5) D.c. generators are used for electrolytic processes such as electroplating. Large d. c. generators are employed in certain manufacturing processes, such as steel making.

6) The d.c. generator of small capacities is used for various special purposes such as arc welding, automobile generators, train lighting systems, etc. It also finds rather extensive use in connection with communication systems.

Переведите на русский язык в письменной форме абзацы 1,2,4, 5 и 6.

5. Найдите соответствующие ответы на вопросы и напишите их в той последовательности, в которой заданы вопросы:

Вопросы

1. What is the function of a motor?

2. What are the essential parts of a generator?

3. Where are large generators employed?

4. What special purposes are generators of small capacities used?

5. What device converts mechanical energy into electrical one?

Ответы

a. They are employed in certain manufacturing processes, such as steel making.

b. A generator.

c. It transforms electric energy into mechanical energy.

d. They are used in arc welding, automobile generators, train lighting systems, etc.

e. They are: a) the magnetic field, which is produced by permanent magnets or electromagnets; b) a moving coil of copper wire, called the armature, wound on a drum.

 

6. Закончите предложения, выбрав соответствующий вариант окончания:

1.The essential parts of a generator are: …

a) the magnetic field, which is produced by permanent magnets or electromagnets;

b) a moving coil of copper wire, called the armature, wound on a drum.

c) stator and rotor.

2.The enormous energy of steam engines, gas engines, and water turbines can now be

transformed into electricity …

a) by means of motors.

b) by means of generators.

3.The d.c. generator of small capacities is used...

a) for various special purposes such as arc welding, automobile generators, train lighting

systems.

b) in certain manufacturing processes, such as steel making.

4. A device for converting mechanical energy into electric energy is called...

a) a generator.

b) a motor.

c) a transformer.

Вариант 4

1. Найдите в правой колонке русские эквиваленты слов и словосочетаний:

1 alternating current a. применение

2. device b. изолированная катушка

3. application c. проволока, провод

4. insulated coil d. толщина

5. primary/secondary winding e. прибор, устройство

6. load f. оборот, виток

7. ring of iron g. высококачественная сталь

8. wire h. частота

9. strand i. нагрузка

10. high-grade steel j. петля, контур

11. frequency k. железное кольцо

12. thickness l. переменный ток

13. loop m. жила, кабель

14. turn n. первичная/вторичная обмотка

 

2. Переведите на русский язык встречающиеся в тексте интерна­циональные слова:

transformer, principle, operation, electrical energy, voltage, in parallel, function, maximum efficiency, factor, material, design.

3. Простите текст и выполните следующие за ним упражнения:

Transformers

1) One of the great advantages in the use of the alternating current is the ease with which the voltage may be changed by means of a relatively simple device known as a transformer. Although there are many different types of transformers and a great variety of different applications, the principles of operation are the same in each case.

 

2) A transformer consists of two insulated coils of wire linked with a ring of iron. The coils are called high-voltage and low-voltage windings, or primary and secondary windings. The primary winding is connected to the source of energy, and secondary is connected to the load. The high-voltage winding is designed for the higher voltage, and has the greater number of turns. The ring of iron is called the core.

3) Each coil consists of some loops of wire. Several strands may be used in parallel but electrically insulated from each other, from the core and from the other coil.

4) The core consists of thin sheets of high-grade silicon steel. The thickness depends somewhat on the frequency at which the transformer is to operate.

5) The main function of a transformer is to transform electrical energy from one alternating voltage to another. To transform large amounts of energy with maximum efficiency, many factors must be considered in determining the materials, design, and arrangement of the primary and secondary coils and the core.