Методические указания для самостоятельной работы
Бакалавров заочного обучения
по направлению 110800 Агроинженерия
профиль Электрооборудование и электротехнологии
УФА – 2012
УДК 811
ББК 81.2 Англ
М 54
Рекомендовано к изданию методической комиссией энергетического факультета Башкирского ГАУ, протокол № от ноября 2012 года
Составитель: к.с.н., доцент кафедры иностранных языков
Р.М. Нутфулина
Рецензент: к.ф.н., доцент кафедры иностранных языков Г.С. Тукаева
Ответственный за выпуск: заведующий кафедрой иностранных языков, к.ф.н., доцент О.Н. Новикова
От автора
Цель сборника – знакомство и обучение бакалавров направления «Агроинженерия» развитию навыков самостоятельной и аудиторной работы над литературой по данному направлению, умению понимать и переводить научно-технические тексты, что соответствует требованиям программы по английскому языку и рассчитано на бакалавров, имеющих начальную языковую подготовку.
Все тексты подверглись адаптации и сокращению. Задания способствуют усвоению и закреплению лексики и дальнейшему развитию беспереводного понимания текстов на английском языке.
Помощь при переводе текстов может оказать терминологический словарь, включенный в сборник.
Contents
| 1 Direct current and alternating current | |
| 2 Difference between A.C. and D.C. | |
| 3 Two main types of circuit connection | |
| 4 Resistance and Resistivity | |
| 5 Measuring units and instruments | |
| 6 Conductors | |
| 7 Semi-conductors | |
| 8 Dynamo | |
| 9 Relays | |
| 10 Electric cells | |
| 11 Capacitors | |
| 12 Transmission of electric power | |
| 13 Transformers | |
| 14 The atomic power plant | |
| 15 The operation of atomic power plant | |
| 16 Electric lines and their efficiency | |
| 17 Electric power | |
| 18 Thermal electrical plants | |
| 19 How electricity is generated | |
| 20 Sources of electrical energy | |
| 21 Electric shock. Safety electric system | |
| English – Russian vocabulary |
Direct current and alternating current
We know that current is the flow of electricity through a circuit. There are two main types of current: direct and alternating. When electrons flow in one direction only, the current is called a direct current. When electrons flow first in one direction and then in another in a periodic manner, the current is called an alternating current. An alternating current is a current that changes its direction of flow through a circuit in a periodic manner. Alternating current flows in cycles. The number of cycles per second is termed the frequency of current. In a 60-cycle alternating current circuit, the current flows in one direction 60 times per second and in the other direction 60 times per second.
A standard frequency has a great advantage since different electrical systems can be interconnected.
(670)
1.1 Test. Choose the correct variant
1. Direct current …
a) changes its direction of flow
b) flows in one direction
2. The frequency of the circuit is …
a) the number of cycles per minute
b) the number of cycles per second
3. A standard frequency has …
a) great advantages
b) disadvantages
Answer the questions
1. What is current?
2. What types of current do you know?
3. What type is termed a direct current (an alternating current)?
4. In what manner does an alternating current flow?
5. What is frequency?
Difference between A.C. and D.C.
A direct current (D.C.) flows continuously through a conducting circuit in one direction only. It is unidirectional in character. An alternating current (A.C.) continually reverses in direction. Starting from zero, it grows in one direction, reaches a maximum, dies down to zero again. Then it rises in the opposite direction, reaches a maximum, again dying down to zero. It is thus changing in magnitude and in direction.
High voltages are desirable for the economic transmission of a given amount of electric power. If the transmission voltage is 100 volts the current must be 10,000 amperes. If the transmission voltage is 10,000 volts the current is only 100 amperes. The cross – section of the cables transmitting the power is determined by the current.
There is the most important factor that it is easy to transform a.c. power from one voltage to another by means of transformer. The transformer also enables to step down voltage at the receiving end of the transmission line.
(820)
2.1 Translate the following word combinations used in the text: in one direction only, unidirectional, in the opposite direction, economic transmission, amount of electric power, high-voltage cable, by means of transformer, transmission line.
Answer the questions
1. What is the difference between A.C. and D.C.?
2. What are high voltages desirable for?
3. Why is high-voltage cable cheaper?
4. What is transformer used for?