Контрольная работа по Английскому языку на тему: "Transformers"

Task № 1. Translate the following text in the written form

The Construction of a Transformer

A transformer is a device for transforming electrical energy at one voltage into electrical energy at another voltage, and consists of two electrically-distinct windings which are so arranged that the magnetic flux associated with one winding also threads through the other. When an alternating current is passed through one winding the magnetic flux first rises to full value in one direction, falls to zero, rises again to a maximum value in the opposite direction, and falls again to zero and so on. This varying magnetic flux induces in the other winding alternating EMF.....

 

Task № 2. Arrange in order and then translate:

a) sentences in which ing-form is the Participle;
b) sentences in which ing-form is the Gerund.

1. Current consists of moving electrons.

2. Current flowing in one direction only is called a direct current.

3. A voltmeter is an instrument for measuring voltage.

4. Measuring current is not difficult.

5. The generator supplies direct current serving us in many fields.

6. An electric current passing through a wire heats it.

7. While converting chemical energy into electrical energy, we use a battery.

8. Before making the experiment we prepared all the necessary devices.

9. An EMF is developed by moving a conductor in a magnetic field.

10. In its usual form a transformer is a device without moving parts.

11. We use copper constructing devices.

12. The function of a commutator is reversing or commuting the alternating current of a generator.

13. The transformer is a device converting an alternating current at one voltage into an alternating current at a different voltage.

14. Changing the resistance of a circuit we control the flow of a current in the circuit.

Task 3. Arrange in order and then translate:

a) sentences in which -ing-form is the Gerund;
b) sentences in which -ing-form is a verbal noun and translate them.

1. Autotransformers are employed for starting a.c. motors and in other cases.

2. The winding may consist of two portions of wire of different cross-sections.

3. Little of the input energy is wasted in the process of changing voltage.

4. The transformers used in transmission lines ensure transferring electricity without great losses.

5. Potential transformers are connected with voltmeters with a full-scale reading of 300 volts.

6. Constant-current transformers are employed in gaseous lamps for street lighting.

7. A current transformer comprises a magnetic circuit in the form of iron stampings assembled together.

8. A current transformer may serve in conjunction with an ammeter for measuring current of low value.

9. Changing in power input is mainly made through changing in the primary power factor.

10. At the beginning the distance between the primary and the secondary windings must be the greatest.

11. One winding is designed for receiving the energy from the supply circuit.

12. The cores of transformers are built up from punchings of thin silicon sheet steel.

13. The distant transmission of power requires the using of an alternating current.

14. Changing the resistance of a circuit is a method of controlling the flow of a current in the circuit.

Task № 4. Read the following text and copy out all ing-forms. Define their function, if it is a participle, a gerund or a noun.

Step-up and Step-down Transformers

The function of transformers is changing the voltage from one value to another. This is accomplished by having more turns on one winding than on the other.

Thus, if the primary winding has 200 turns and the secondary has 1000 turns, then the voltage available at the secondary terminals will be 1000:200=5 times as great as the EMF impressed upon the primary. The ratio of the number of turns in the high-voltage winding to the number of turns in the low-voltage winding is called the ratio of transformation.

When the transformer is used for delivering energy at a higher voltage than that at which energy is received, it is called a step-up transformer. When the transformer is used for lowering the voltage, it is called a step-down transformer.

Any desired alternating EMF may be provided by properly proportioning the number of turns on the windings of a transformer.

Transformers are much used in transmitting and distributing electrical energy over long distances.

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Task № 5. Translate into English using ing-forms.

1. Трансформатором называется устройство, служащее для повышения или понижения напряжения в цепи переменного тока.

2. Простой трансформатор состоит из стального сердечника и двух обмоток, помещенных на этом сердечнике.

3. Основной металл, из которого выполняются обмотки, это медь.

4. Трансформатор может служить как для повышения напряжения, так и для понижения его.

5. Повышающий трансформатор имеет число витков вторичной обмотки больше, чем в первичной.

6. Увеличение индукции магнитного потока в трансформаторе достигается при помощи стального сердечника.

7. Если трансформатор применяется для преобразования переменного тока высокой частоты, то он может не иметь стального сердечника.

8. Передача энергии от первичной обмотки к вторичной осуществляется переменным магнитным потоком.

9. Во вторичной обмотке индуцируется электродвижущая сила, зависящая от числа витков обмотки, величины магнитного потока и скорости его изменения.

10. Понижающий трансформатор имеет число витков вторичной обмотки меньше, чем в первичной.
    
     

    Task № 7. Translate sentences into English in the written form

Трансформатор служит для повышения или понижения напряжения в цепи переменного тока.

Трансформатор состоит из стального сердечника и двух обмоток, которые помещены на этом сердечнике.

Первичная обмотка соединяется с зажимами источника тока.

Потребитель электроэнергии подсоединяется к вторичной обмотке.
Обмотки изготовляются из изолированного медного провода.
 

Передача энергии от первичной обмотки к вторичной осуществляется посредством переменного магнитного потока.

Увеличение индукции магнитного потока в трансформаторе достигается при помощи стального сердечника.

Если трансформатор применяется для преобразования переменного тока высокой частоты, стальной сердечник может не использоваться.

Трансформатор только преобразовывает электрическую энергию и не может служить ее источником.

 

Task № 8. Translate the text orally

A voltage transformer which is also called a potential transformer, may be defined as an instrument transformer for transforming voltage from one value to another. This transformer is usually a step-down type because it is used when a meter is installed for using a high-voltage system.....

 

Task № 9. Найдите в тексте английские эквиваленты следующим словосочетаниям:

1. Трансформатор напряжения

2. Измерительный трансформатор

3. Понижающий трансформатор

4. Счетчик устанавливается

5. Полоски железа

6. Общепринятая практика

7. Отдельный агрегат

8. Однофазный трансформатор напряжения

9. Броневой трансформатор

10. Стержневой трансформатор

11. Средний сердечник

12. Источник высокого напряжения

13. Тонкий провод

14. Ряд отдельных секций

15. Прилегающий к сердечнику

Task № 10. Определите, являются ли следующие утверждения истинными или ложными (в письменной форме):

1. A voltage transformer is a step down type.

2. A potential transformer is a step up type.

3. A voltage transformer is an instrument type.....
    

   Task № 11. Complete the sentences using the text.
   
   1. ​​​​​​​A potential transformer is used for transforming:

a) low voltage
b) current
c) resistance
d) high voltage.

2 . The core of a voltage transformer consists of:
a) separate sections
b) single units
c) copper turns
d) iron strips.

3. The primary winding is connected to:
a) a simple-phase system
b) high-voltage system
c) high-voltage supply
d) a three-phase system.

4. The secondary winding is mounted on:
a) the primary winding
b) a tube
c) a core
d) a limb

5. The primary winding consists of:
a) insulating material
b) a magnetic circuit
c) fine wire
d) iron strips....

 

Task № 12. Translate the text orally

Functions of Transformers

A transformer is a device widely used for changing voltage and current relations in alternating-current electric circuits without serious loss in the transformation process. Without transformers, the present long-distance transmission systems would not be feasible.

Since it is a static device, the transformer requires little attention and expense for maintenance. It is mounted in the open upon poles or platforms or upon the ground.....

 

Task № 13. Define if the following statements are true or false (in the written form):

1. Transformers connect systems of different voltages.

2. Transformers are used not only to maintain constant terminal voltage.

3. It is usually a double-function device.

4. A transformer can change only voltage.

5. Transformer maintenance is very expensive.

6. A transformer can step-up and step-down voltage at the same time.

7. A transformer is used as an intermediary between transmission and distribution systems.

8. To transform high voltage to medium voltage, a step-down transformer is used.

Task № 14. Complete the sentences using the text:

1. Transformation of alternating current by a transformer results in:
   a) serious losses
   b) no serious losses
   c) decreasing voltage
   d) increasing voltage

2. Long-distance transmission lines are feasible:
   a) due to heating wires
   b) after stepping down voltage
   c) without transformers
   d) only with transformers

3. Transformers require little maintenance because:
   a) they are mounted on the ground
   b) they have moving parts
   c) they have no moving parts
   d) they are an intermediary

4. The place of a transformer is:
   a) between a generator and transmission line
   b) in the distribution system.....