Виконання вправ на закріплення граматичної теми

Вправа 13. Перекладіть речення українською.

1. Tractor driver objects to mechanic’s too quick repairing of the tractor. 2. I cannot help telling you the safety .3. He was accused of making fatal electrical equipment related accident. 4. He gave up quarrelling with the electrician. 5. I insist on fulfilling all safety instructions. 6. I look forward to repairing the wiring from you.

Вправа 14. Перекладіть речення англійською.

1. Електрик погодився перевірити ватметри, які встановлені на щитах. 2. Ця електропроводка потребує ремонту. 3. Продовжуйте перевіряти заходи безпеки. 4. Уникайте перегріву електродвигуна. 5. Він не проти ще попрацювати в лабораторії. 6. Я здивований його підготовкою з безпеки роботи на виробництві. 7. Він наполягав на тому, щоб встановити новий пристрій. 8. Вибачте мене за розмову. 9. Я не проти працювати у вільний час. 10. Викладач заперечував проти моїх запізнень.

Заняття 41

Тема: Трансформатори. Призначення, принцип дії та будова трансформатора

Граматичний матеріал: Комплекси з герундієм

Вправа 1. Прочитайте та перекладіть лексику за допомогою словника.

сonvert [ʹkɒnvɜ:t] step down [step daʋn]

wound [wu:nd] amperage [ʹæmp(ə)rıdʒ]

сore [kɔ:] assume [əʹsju:m]

merely [ʹmıəlı] winding [ʹwaındın]

tube [tju:b] eddy [ʹedı]

prohibitive [prəʹhıbıtıv] hysteresis [͵hıstəʹri:sıs]

the latter [ðə ʹlætə] friction [ʹfrıkʃ(ə)n]

set up [set ʌp] a.c.supply [eı si: səʹplaı]

step up [step ʌp] transmitter [trænzʹmıtə]

turn [tɜ:n] sufficiently [səʹfıʃ(ə)ntlı]

coil [kɔıl] iron core [ʹaıən kɔ:]

therein [ðe(ə)ʹrın] reactance [rıʹæktəns]

ratio [ʹreıʃıəʋ] eliminate [ıʹlımıneıt]

insulating material [ʹınsjʋleıtıŋ məʹtı(ə)rıəl]

Вправа 2. Прочитайте та перекладіть текст українською.

Transformers

U nlike the generator, a transformer cannot be used to convert mechanical energy into electrical energy, it being able to transform electrical energy from one circuit at the same or some other voltage.

Essentially, a transformer consists of two coils, not electrically connected to each other, but wound over a common core. The core may also be of open type, or it may be merely a tube of some insulating material, the latter being referred to as an air core.

If a varying voltage be applied to the primary coil, the electromagnetic field set up around the coil will rise and fall in accordance with the e. m. f. variations applied. This moving field cuts the turns in the secondary coil and induces an e. m. f. therein. The value of this induced e. m. f. depends upon the strength of the applied e. m. f. and the ratio of se­condary turns to primary turns. Should there be twice as many turns in the secondary as in the primary, the voltage in the secondary would be twice that applied to the primary. If there were half as many turns in the secondary, the voltage would be half that applied to the primary. This voltage step up or step down in proportion to turn ratio will hold good for all combinations. Where the voltage is raised, however, amperage is lost in the same proportions, and vice versa. Therefore, the power in watts supplied to the transformer is the same as that drawn from it, assuming the transformer to be 100 per cent efficient. The copper losses, or ohmic re­sistance of the windings, and the core losses due to the induc­tion of eddy currents in the core material, as well as hyste­resis or molecular friction caused by changing polarity of the current applied, all combine to reduce modern transfor­mer efficiency to about 90 per cent.

Transformers are classed according to the use they are de­signed for. Where it is desired to step up a low-voltage a. c. supply to a value useful for radio receivers and transmitters, a power transformer is used. The windings are sufficiently heavy to carry the current without undue heating, and the secondary may consist of two or more separate windings to provide various voltages from one input source.

As the iron core increases, the inductive reactance of the transformer increases, and inasmuch as this type of reactance also increases with the frequency of the applied alternating current, there is a limit to the frequencies that can be efficiently used in transformers with metallic cores. Where very high-frequency alternating current is used such as in the r-f circuits of receivers and transmitters, air core transformers must be used to eliminate prohibitive core losses.

Вправа 3. Прочитайте слова за викладачем.

Сore, source, vary, merely, circuit, winding, design, frequency, primary, secondary, molecular, essentially, sufficiently, efficiency, eliminate, prohibitive.

Вправа 4. Прочитайте¸перекладіть та запамятайте наступні терміни.

Сore, secondary turns, primary turns, step up, step down, winding, eddy currents, inductive, reactance.

Вправа 5. Знайдіть в тексті англійські еквіваленти і запам’ятайте їх.

Так само, як; і навпаки; по суті; просто; у відповідності з; мати силу (бути справедливим); тому; оскільки; згідно, по мірі того; однак.

Вправа 6. Дайте відповіді на питання до тексту.

1. What is a generator used for?

2. What is a transformer used for?

3. What does a transformer consist of ?

4. What kinds of cores do you know?

5. How does the electromagnetic field around the primary coil change if a varying voltage is applied to it?

6. What does the va­lue of the induced e. m. f. depend upon?

7. How are transformers classed?

8. When does the inductive reactance of the transformer increase?

9. Where must air core transformers be used?

Вправа 7. Перекладіть речення, звертаючи увагу на різні значення виділених слів і словосполучень.

1. In a generator the pole pieces are always even in number. Even the slightest changes in frequency can be detected by the new device. 2. Carbon brushes rest upon the slip rings fixed to the arma­ture. The machine is at rest. The efficiency of the machine is 85%, the rest of the power being lost in the resistance to friction, 3. A gene­rator with two sets of field poles, whose armature turns 1 complete re­volution per second (rps) would have a frequency of 2 cycles. 4. The strength of an electromagnet with a given core is known to be propor­tional to the number of ampere turns. 5. Steam may be passed into an engine to produce mechanical energy. This in its turn may drive a dy­namo to produce electrical energy. 6. We use soft iron not only because of its high permeability but because its low retentivity allows very little residual magnetism when the current is turned off. 7. An electro­chemical cell which delivers electrical energy by virtue of the diffe­rence of potential between its electrode is known as a galvanic cell. 8. Electrolytes conduct the current owing to the presence of ions both positive and negative. 9. The molecules are held in position due to the rigidity of the crystal. 10. Heating causes the magnet to be demagnetized on account of the fact that it permits the molecules to adjust themselves to equilibrium position.

Вправа 8. Опишіть структуру трансформатора.

Граматичний матеріал: Комплекси з герундієм

Герундій, як інфінітив і дієприкметник, може утворювати синтаксичний комплекс, який виконує роль складного члена речення і рівноцінний підрядному реченню.

Комплекс з герундієм складається з двох частин: перша частина комплексу - присвійний займенник або іменник у присвійному відмінку, який є означенням до герундія, друга - герундій. Excuse my interrupting you. (Пробачте, що я перебив вас.) Would you mind my opening the window? (Ви не заперечуєте проти того, щоб я відчинив вікно?) I don't like his coming here. Who told you of Ann's being there?

Першою частиною герундіального комплексу може бути також особовий займенник в об'єктному відмінку або іменник у загальному відмінку. I don't like him coming here. (Порівняйте: I don't like his coming here.) Who told you of Ann being there? (Порівняйте: Who told you of Ann's being there?)

Герундіальний комплекс виконує в реченні такі функції:

1. складного прямого додатка; після дієслів to mind, to excuse, to forgive, to pardon, to understand герундій вживається, як правило, в комплексі:

Do you mind my opening the window?

You must forgive our coming late.

Please excuse my disturbing you.

2. складного прийменникового додатка:

Did your mother agree to your going on this trip?

Do you object to my taking part in the competition?

3. складного означення:

Is there any objection to my sitting here?

I had no idea of your leaving tomorrow.

4. складного підмета:

Your coming here always gives us much pleasure.

Our going there now won't help much.

5. складної обставини (завжди з прийменником):

I can never do anything without your (you) interfering.