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1. a) Cover the right column and read the English words. Translate them into Russian and check your translation.
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6. Say a few words about your electrical engineering laboratory. Say what power sources and what loads are utilized there. Have a talk with your groupmate about their types and their operation.
Unit Twenty-Five [25]
1. a) Cover the right column and read the English words. Translate them into Russian and check your translation.
b) Cover the left column and translate the Russian words back into English.
| efficiency | [ɪ ˈ fɪ ʃ ə nsi] | отдача, эффективность |
| ignorance | незнание, неведение | |
| dependence | зависимость | |
| cost | стоимость | |
| loss | потеря | |
| length | длина | |
| to ignore | не принимать во внимание | |
| to depend (on) | зависеть (от) | |
| to exceed | [ɪ kˈ siː d] | превышать |
| long | длинный | |
| exceedingly | чрезвычайно, очень | |
| per cent | процент |
2. Read the words and put down their Russian equivalents:
| [laɪ n] | line | ___________________________ |
| [ˈ steɪ ʃ ə n] | station | ___________________________ |
| [ˌ endʒ ɪ ˈ nɪ ə ] | engineer | ___________________________ |
| [ˌ endʒ ɪ ˈ nɪ ə rɪ ŋ ] | engineering | ___________________________ |
3. Put down the nouns corresponding to these verbs. Follow the model.
Model: to act - action
| to ignore - | _________________ | to produce - | ___________________ |
| to depend - | _________________ | to use - | ___________________ |
| to cost - | _________________ | to lose - | ___________________ |
4. Translate into Russian:
| a. line efficiency | ______________________________ | ||
| voltage loss | ______________________________ | ||
| power station | ______________________________ | ||
| b. interdependent values | ______________________________ | ||
| interconnected sources | ______________________________ | ||
| changing power efficiency | ______________________________ | ||
| c. exceedingly high power losses | ______________________________ | ||
| exceedingly inefficient energy sources | |||
| ____________________________________________________________ | |||
| d. One can ignore these exceedingly low power losses. | |||
| ____________________________________________________________ | |||
| One should take into consideration the interdependence of these values. | |||
| ____________________________________________________________ | |||
| One should not ignore the high cost of these installations.
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| ____________________________________________________________ | |||
Electric Lines and Their Efficiency
Wires are used to deliver electric power and to interconnect different components of electrical installations. Conductors used for electric wiring are commonly produced of copper and aluminium. Aluminium is widely used nowadays due to its low cost. Copper is also widely used in electrical engineering but its cost is much higher.
Wires connecting the components of various installations may be insulated. They may also be used without insulation. Since in short lengths of wire power loss is exceedingly low one can ignore it. In long wires (longer than 10 m), power loss cannot be ignored since it is rather high. Power loss in a line should not exceed a definite value. If this value is exceeded the line becomes inefficient.
One should know that the efficiency of a line is not constant - it may change. The value of the line efficiency depends on the load: the greater the load the lower is the line efficiency. At voltage losses of 2 to 5 per cent the efficiency of a line is 98-95 per cent. Protecting devices, fuses and relays are used to protect the circuit against overcurrents and short-circuits.
5. Complete the sentences using the correct variant:
| 1. Aluminium is used due to its | a) high cost. b) low cost and high efficiency. |
| 2. Cross-section of different conductors | a) varies. b) is the same. |
| 3. Power loss can be ignored | a) in short wires. b) in long wires. |
| 5. Electric lines nowadays are | a) efficient. b) inefficient. |
| 6. Installations are protected | a) by switches. b) by fuses. |
6. Complete these sentences using while. Follow the model on page 13:
1. The cost of aluminium is comparatively low while ….
2. In a short length of wire power loss is extremely low while ….
3. The greater the load the lower is the efficiency of the line ….
7. Answer these questions:
1. Why is aluminium widely used nowadays?
2. Is its cost very low or comparatively low?
3. What is the cross-section of copper conductors?
4. May one ignore power loss in short wire? Why?
5. What does the efficiency of a line depend on?
6. What are fuses used for?
7. When does a line become inefficient?
8. Think of three questions about this extract and put them to your groupmate.
conˈ sumer - потребитель; relation - отношение
When electric energy is produced at the power station, it is to be transmitted over electric wires to the consumer. Wire conductors offer resistance to the current flow; the longer the wire, the greater is its resistance to the current flow. Accordingly, the higher the offered resistance, the greater are the heating losses in the wire.
Unit Twenty-Six [26]
1. a) Cover the right column and read the English words. Translate them into Russian and check your translation.
b) Cover the left column and translate the Russian words back into English.
| area | [ˈ ɛ ə rɪ ə ] | площадь, область |
| distance | расстояние | |
| network | сеть электролиний | |
| support | опора, мачта | |
| cord | провод | |
| bus | шина | |
| enterprise | [ˈ entə praɪ z] | предприятие |
| to term | называть, именовать | |
| to divide | [dɪ ˈ vaɪ d] | делить, разделять |
| to support | поддерживать | |
| to distribute | распределять | |
| accordingly | соответственно | |
| as to | … что касается; … что до | |
| long distance | большое расстояние | |
| length of transmission lines | длина линий передачи | |
| power consumption | потребление энергии | |
| distribution centre | распределительный центр | |
| city area | район городской застройки |
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2. Put down the Russian for:
| interdependent city areas | _________________________________ |
| interacting underground lines | _________________________________ |
| interconnected overhead lines | _________________________________ |
| transmitting power lines | _________________________________ |
| transmission and distribution lines | _________________________________ |
| overhead lines | _________________________________ |
| step-down transformer | _________________________________ |
| indoor lines | _________________________________ |
| underground lines | _________________________________ |
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