Гаоу спо «альметьевский политехнический техникум»

РЕСПУБЛИКА ТАТАРСТАН

МИНИСТЕРСТВО ОБРАЗОВАНИЯ И НАУКИ

ГАОУ СПО «АЛЬМЕТЬЕВСКИЙ ПОЛИТЕХНИЧЕСКИЙ ТЕХНИКУМ»

 

 

МЕТОДИЧЕСКИЕ УКАЗАНИЯ ДЛЯ СТУДЕНТОВ ПО ВЫПОЛНЕНИЮ ПРАКТИЧЕСКИХ РАБОТ

по дисциплине	«Английский язык»
для специальности	140613 «Техническая эксплуатация и обслуживание электрического и электромеханического оборудования»

 

 

 

 

2009

 

Одобрена на заседании                                      цикловой комиссии                                            Протокол №        от «»                   2009г.              Председатель цикловой комиссии                   ____________ Л.М.Усманова

УТВЕРЖДАЮ Зам. директора по УР  _______Л.С. Мавлявеева «  »                      2009 г.

 

                                                        

 

             

Составили	Давлетшина Г.Г.   Сафина Г.Т.	преподаватели  английского языка ГАОУ СПО «Альметьевский политехнический техникум»
Рецензенты	Хусаинова Р.Р.	к.п.н. доцент кафедры иностранных языков Альметьевского государственного нефтяного университета
	Фасхутдинова Р.М	преподаватель английского языка ГАОУ СПО «Альметьевский политехнический техникум»

 

Методические указания для студентов по выполнению практических работ по дисциплине «Английский язык» представляют собой сборник лексико-грамматического материала для студентов III и IV курсов. Включает в себя лексико-грамматический практикум, состоящий из 27 тем.

 

СОДЕРЖАНИЕ

 

Введение…………………………………………………………………………………..	4
1 Тематика практических работ……………………………………………………….	5
2 Методические указания для студентов по выполнению лабораторной (практической) работы………………………………………………………………….	6
3 Список литературы…………………………………………………………………….	71

 

 

ВВЕДЕНИЕ

Методические указания для студентов по выполнению практических работ по дисциплине «Английский язык» составлены в соответствии с учебным планом и рабочей программой, утвержденной в 2009 году. В программе иностранный язык рассматривается как средство общения. Ему отводится значительная роль в повышении образовательного и культурного уровня личности студента.

Программа рассчитана на преподавание иностранного языка 2 часа в неделю, в том числе на II-III курсе течение 166 часов.

Организация учебной деятельности представлена в виде циклов уроков, состоящих из 5-7 занятий, которые организуются по ситуативно-тематическому принципу и объединяются для решения одной учебной задачи.

Основной целью курса «Иностранный язык» является обучение практическому владению разговорно-бытовой речью и деловым языком специальности для активного применения, как в повседневной жизни, так и в профессиональной деятельности.

 Учебное пособие для  специальности 140613 «Техническая эксплуатация   и обслуживание электрического и электромеханического оборудования» ставят целью развитие навыков чтения и понимания адаптированных текстов по специальности, ознакомление с основной профессиональной лексикой, формирование умений беседовать на профессиональную тематику. Для достижения поставленных целей в   методических указаниях предусмотрена регулярная, от урока к уроку, учебная деятельность по созданию словаря активной лексики, включающего наиболее употребительные для данной специальности термины и слова общетехнического значения. Кроме того, предусмотрена учебная деятельность, направленная на активизацию предложенных грамматических и лексических единиц посредством разнообразных заданий и упражнений.

Специальные задания направлены на активизацию мыслительной деятельности студентов.   

Методические указания для студентов по выполнению практических работ дополняются сборником контрольно-измерительных материалов, составленным на основе изученного лексико-грамматического минимума и позволяющим обобщить, систематизировать рассмотренную ранее информацию.

 

 

ТЕМАТИКА ПРАКТИЧЕСКИХ РАБОТ

Номер    темы	Содержание практических занятий	Кол – во часов
1	Addition and subtraction	2
2	Multiplication and division	2
3	Common and decimal fractions	2
4	Ohm's law	2
5	Electric circuit	6
6	Meters	6
7	Resistors	6
8	Electric cells	6
9	Capacitors	6
10	Transformers	6
11	Types of current	6
12	Filters	6
13	Electron tubes	6
14	Use of electron tubes	6
15	Electromagnetic relay	6
16	Fuses	4
17	Components of electric circuits	4
18	Practical units	6
19	Branches of electricity	6
20	Electric motors	6
21	A.C. electric motors	6
22	Electric generations and motors	6
23	Magnetism	6
24	The storage battery	6
25	How generator works	6
26	Electrical system	6
27	An electric car	4
Всего:		140 часов

МЕТОДИЧЕСКИЕ УКАЗАНИЯ ДЛЯ СТУДЕНТОВ ПО ВЫПОЛНЕНИЮ ПРАКТИЧЕСКОЙ РАБОТЫ

ПРАКТИЧЕСКАЯ РАБОТА №1

ADDITION AND SUBTRACTION

Цель: Введение и активизация в речи лексики по теме «Сложение и вычитание».

Оборудование: комплект тестов, раздаточный материал.

                                          Vocabulary

I. Learn the words and expressions.

Addition Subtraction Plus Minus To add To subtract To equal

сложение вычитание плюс минус складывать, прибавлять вычитать равняться, быть равным

5 + 7 = 12 - five plus seven equals twelve

66 + 13 = 79 - sixty-six plus thirteen is equal to seventy-nine

a + b = с - a plus b is equal to с

15-6 = 9- fifteen minus six equals nine

81 - 33 = 48 - eighty-one minus thirty-three is equal to forty-eight

с - b = a - с minus b equals a

I. Solve these problems and read them:

 

99 + 77 = _______        61-50 =_____________ 114 + 316 =______  b + d =_________

8-3=_____ 47-18 =___ 1,203+419= d-c =_____________

315 + 145 =________      859 - 600 =________      4,444 + 7,777 =_____ a-b =_____________

II. Pair work. Think of six problems of your own. Put them down. Ask your group mate to solve them.

ПРАКТИЧЕСКАЯ РАБОТА № 2

MULTIPLICATION AND DIVISION

Цель: Введение и активизация в речи лексики по теме «Умножение и деление».

Оборудование: комплект тестов, раздаточный материал.

 

                                        Vocabulary

I. Learn the words and expressions.

Multiplication To multiply Multiplied by Once Twice Three times Four times Division To divide Divided by

умножение умножать умноженное на один раз дважды, два раза три раза четыре раза деление делить деленное на

1 x 1 = 1- once one is one

2 x 2 = 4- twice two is four

3 x 3 = 9- three times three equals nine

4 x 4= 16 - four times four is equal to sixteen

12 x 10 = 120 - twelve multiplied by ten (by) is equal to one hun­dred and twenty

a • b = ab

35: 7 = 5- thirty-five divided by seven equals five

1000: 25 = 40 - one thousand divided by twenty-five is equal to forty

d: b = c

I. Solve these problems and read them:

10 x 7=_______ 100 x 100 =___ 234 x 6 =_____

49: 7 = _______ 175: 25 =_____ 12 x 12=______

13x3 =______ 618:6=______ 33: 33 =____

749: 7 =______ 3,550 x 5 =____ 10,660: 10=___

ПРАКТИЧЕСКАЯ РАБОТА № 3

ПРАКТИЧЕСКАЯ РАБОТА № 4

 

OHM ' S LAW

Цели: Введение и активизация в речи лексики по теме «Закон Ома».

Оборудование: комплект тестов, раздаточный материал.

                                           Vocabulary

I. Learn the words and expressions.

Current                                                                 электрический ток

Resistance                                                         сопротивление

Voltage                                                                  вольтаж, напряжение

To suppose                                                        предполагать

Law                                                                     закон

 

 

R =  Resistance equals voltage divided by current.

 

I =  Current equals voltage divided by resistance

 

V = IR Voltage equals current times resistance.

 

 

ПРАКТИЧЕСКАЯ РАБОТА № 5

                          

                              ELECTRIC CIRCUIT

Цели: Введение и активизация в речи лексики по теме «Электрическая цепь».

Оборудование: комплект тестов, раздаточный материал.

 

                                        Vocabulary

I. Learn the words and expressions.

Circuit                                                                   цепь, контур

Conductor                                                                  проводник

Function                                                                    назначение

Difference                                                              разница

Open                                                                            обрыв

Short                                                                       короткое замыкание

Trouble                                                                  повреждение

No                                                                           никакой, нисколько

To reduce                                                             сокращать

To supply                                                             снабжать

To connect                                                              связывать

To compare (with)                                               сравнивать (с)

To pass through                                                   проходить через

To result in                                                            приводить к, результатом

To result from                                                      следовать, проистекать из

 

 

IV. Add necessary letter.

Circ-it, vol-age, resi-tor, curr-nt, sou-ce, eq-al, o-m, tro-ble, cond-ctor. 

V. Finish the sentences.

1. The circuit consists of….

2. A voltage source supplies….

3. A conductor connects……..

4. A trouble in a circuit may result…….

5. Current passes through………

VI. Complete these sentences, using the correct variant:

1. Circuit consists of          a) resistors and conductors.

                                            b) a voltage source and resistors.

                                             c) a voltage source, a resistor and a conductor.                                                             2. A voltage source             a) conducts current.

                                               b) reduces current.

                                                 c) supplies current

 3. A conductor                    a) connects the elements.

                                             b) supplies voltage.

                                              c) conducts current.

  4. A resistor                       a) connects the elements.

                                             b) supplies current.

                                             c) reduces current.

  5. No current results from   a) an open.

                                            b) a short.

 

 

VII. Solve these problems:

 

1.How much is the current in the circuit if a 60-volt source is connected

to a resistance of 1,600 ohms?

2.How much is the voltage in a circuit having a current equal to 25 amp,

if a 25-ohm resistance is connected to it?

3.A 70.35-ohm resistance is connected to the circuit. How much is the

voltage if the current equals 4.5 amp?

VIII. Pair work. Ask your group mate to compare circuits a and b (see Fig.1)

 

1.What do they have in common?

2.Which of the circuits has a trouble?

3.What does the trouble result from?

4.What does it result in?

 

IX. Answer the following questions:

1.What elements does a circuit consist of?

2.What is the function of a voltage source?

3.What is the function of a conductor?

4.What is the function of a resistor?

5.When is there no current in a circuit?

6.What does an open or a short result in?

ПРАКТИЧЕСКАЯ РАБОТА № 6

METERS

Цели: Введение и активизация в речи лексики по теме «Измерительные приборы».

Оборудование: комплект тестов, раздаточный материал.

 

                                     Vocabulary

I. Learn the words and expressions.

                              измерительный прибор

                             батарея

                              шкала

                             показания на шкале (прибора)

                             клемма

                             положительный

                            отрицательный

                            измерять

             

ПРАКТИЧЕСКАЯ РАБОТА № 7

RESISTORS

 

 

Цели: Введение и активизация в речи лексики по теме «Резисторы».

Оборудование: комплект тестов, раздаточный материал.

 

 

                                       Vocabulary

I. Learn the words and expressions.

Capacity                                емкость

Power                                    мощность

Heat                                      теплота, нагрев

Rate                                      скорость, степень

To produce                           производить

To change                              менять(ся)

To vary                                  варьировать(ся)

Low                                        низкий

High                                      высокий

Fixed                                     постоянный

Any                                        любой

Variable                                переменный

 

 

V. Finish the sentences.

1. A resistor is…………..

2. When current is passing through…………

3. The higher the value of current

4. Resistors are rated……..

5. The watt is the rate…….

6. A resistor is rated as……..

7. If a resistor has a resistance………..

8. Some resistors have………

VI. Complete the sentences using while. Follow the model on page 13.

 

1.The value of a fixed resistor is constant

2.Current-carrying capacity is given in amperes 

3.The lower the value of current, the lower is the temperature of a resis­tor………     

4.An electric source produces energy

 

VII. Solve the problem:

 

What is the maximum current for a resistor having a 5-watt capacity and a resistance of 20,000 ohms?

 

VIII. Pair work. Think of three similar problems of your own. Ask your
group mate to solve them.

IX. Answer the questions.

 

1.What is a resistor used for?

2.When does the temperature of a resistor rise?

3.What element is used to change the value of voltage?

4.How are resistors rated?

5.What types of resistors do you know?

6.When does a resistor get open?

7.What does an open resistor result in?

8.What is the difference between a fixed resistor and a variable resistor?

9.How much is the current-carrying capacity of a two-ohm resistor?

10. What resistors have a variable value?

ПРАКТИЧЕСКАЯ РАБОТА № 8

ELECTRIC CELLS

 

 

Цели: Введение и активизация в речи лексики по теме «Электрические элементы».

Оборудование: комплект тестов, раздаточный материал.

 

                                                  Vocabulary

I. Learn the words and expressions.

Cell                                элемент

Output                                емкость, мощность

Bulb                                              электрическая лампа

To light                                 зажигать, освещать                                                                                                                             To substitute                         увеличивать (ся), возрастать

... and so on                               и так далее

V. Finish the sentences.

 

1. An electric cell is used…………

2. It consists of…………

3. Cells can be connected……………..

4. Electrodes are used……………….

5. When cells are connected in series………….

6. When cells are connected in parallel………….

7. In case a cell has a trouble……….

 

VI. Make up the sentences.

1. to produce supply cell energy is and An electric electric used

2. can be series, parallel in connected Cells series-parallel in and in

3. When together and positive terminals cells their are connected their negative in parallel terminals are also are connected connected.

4. stops operating In has a badly trouble or operates it case a cell

VII. Solve these problems:      

 

1. Suppose that you have four electric cells. The current capacity of each
cell equals 1.5 amp, the voltage output equals 2 V.

a)Connect the cells in series. In what way should it be done?

b)Connect the battery to a circuit whose resistance value equals 15 ohms. What is     the value of current in the circuit?

 

2. Suppose that you have three cells of the same value.

a)Connect them in parallel. In what way should it be done?

b)Connect the second battery to the same circuit: what will it result in?

Suppose that one of the cells stops operating. What should be done in this case?

 

 

VIII. Answer the following questions:

1.What is a cell used for?

2.What does a cell consist of?

3.What is the function of the terminals?

4.In what way are cells connected in order to increase the voltage output?

5.In what way are cells connected in order to increase the current capacity?

6.In what way are the terminals of series cells connected?

7.In what case does a cell stop operating?

8.What should be done in case it stops operating?

ПРАКТИЧЕСКАЯ РАБОТА № 9

CAPACITORS

 

 

Цели: Введение и активизация в речи лексики по теме «Конденсаторы».

Оборудование: комплект тестов, раздаточный материал.

                                                     Vocabulary

I. Learn the words and expressions.

Capacitor	Конденсатор
Insulator	Изолятор
Frequency	Частота
Distance	Расстояние
Advantage	преимущество
Disadvantage	Недостаток
Plate	анод (лампы)
Part	Часть
To apply	прилагать, применять
To move	двигать (ся)
To prevent	предотвращать
Reason	Причина
For this	по этой причине
Besides	кроме того
P rovided that	при условии что

V. Finish the sentences.

1. A capacitor is ………….

2. In the diagram………….

3. The greater the distance between the plates…………….

4. Fixed capacitors have……………

5.  Paper capacitors are……………..

6. A capacitor stops operating…………………

 

 

VI. Complete these sentences using while. Follow the model on page 13:

 

1.The plates of a fixed capacitor cannot be moved to vary the capacity

2. The capacity of a variable capacitor is varied

3. Electrolyte capacitors change their capacity when the temperature changes  

4.The less the distance between the plates, the greater is the capacity...

5.When a capacitor has no trouble it stores energy      

 

VII. Solve these problems:

   Draw a diagram of a circuit consisting of two resistors and two capaci­tors connected in parallel. A battery of four cells is applied to the circuit two ammeters are used: one is connected to the main line, the other- to a parallel branch. What is the function of each element? In what way can one increase the value of resistance in the circuit?

Suppose one of the branches stops operating. What does it result from?

 VIII. Pair work. Put these questions to your group mate and ask him/her to answer them.

1.What is a capacitor used for?

2.What are the main parts of a capacitor?

3.What is the function of insulators?

4.What does the capacity of a capacitor depend on?

5.What is the difference between a fixed capacitor and a variable one?

6.What should be done in order to change a capacitor?

7.What is the relation between the value of capacity and the distance of plates?

8.What type of insulators has variable capacitors?

9.What should be done in case a capacitor has a trouble?

ПРАКТИЧЕСКАЯ РАБОТА № 10

TRANSFORMERS

 

Цели: Введение и активизация в речи лексики по теме «Трансформаторы».

Оборудование: комплект тестов, раздаточный материал.

 

 

                                      Vocabulary

I. Learn the words and expressions.

Core                                                     сердечник  

Winding                                            обмотка

Turn                                                    виток

To step up                                          повышать

To step down                                   понижать

Frequency                                           частота

Due to                                              благодаря, из-за

 

 

Current Transformers

Current transformers are used for operating ammeters, wattcmeters, ant other measuring devices. They produce in the meters a current lower that the measured current but proportional to it.

Current transformers also insulate the instrument from the circuit which is being measured. This is necessary for high voltage circuits.

1.What is a current transformer used for?

2.What type of current does it produce?

 

 

VII. Answer the questions.

What is a transformer used for?

What does a transformer consist of?

What is the function of the primary winding?

What is the function of the secondary winding?

What type of transformer is called a step-up transformer?

What type of transformer is used for high-frequency currents?

What type of transformer is called a step-down transformer?

What type of transformer is used for low-frequency currents?

What is the relation between the numbers of turns in the windings is the value of current?

What are common troubles in a transformer?

What should be done in case a transformer has a trouble?

 

        

 

ПРАКТИЧЕСКАЯ РАБОТА № 11

TYPES OF CURRENT

Цели: Введение и активизация в речи лексики по теме «Виды электрического тока».

Оборудование: комплект тестов, раздаточный материал.

                                                 Vocabulary

I. Learn the words and expressions.

Alternating                                    переменный

Direct                                       прямой

Direction                                   направление

Flow                                    течение

Necessary                                  необходимый

To consider                               рассматривать

Use                                           использование

VI. Make up the sentences.

1. electricity is a a circuit flow of Current through

2. A conducting circuit current flows one a in direction direct through only.

3. of cycles is called per the current second The number of the frequency.

4. It is a.c. to another power easy to transform transformer voltage from one by a

5. a.c. into D.C can be changed but this. seldom is When necessary nec­essary.

 

 

VII. Complete these sentences using while. Follow the model on page 13.

1.An alternating current changes its direction of flow  

2.A direct current flows provided a direct voltage source is applied...

 

   VIII. Answer the following questions:

1.What is current?

2.What types of current do you know?

3.When does a direct current flow?

4.What type of current is called an alternating current?

5.What type of current is called a direct current?

6.What is called the frequency of current?

7.What device is used to transform a.c. power from one voltage to another?

8.Is it often necessary to change a.c. into d.c?

 

ПРАКТИЧЕСКАЯ РАБОТА № 12

FILTERS

 

 

Цели: Введение и активизация в речи лексики по теме «Фильтр».

Оборудование: комплект тестов, раздаточный материал.

  

                                           Vocabulary

I. Learn the words and expressions.

Filter                                          фильтр

Bypass                                   шунт

Choke                                    дроссель

High - pass                                      высокопроходной

Low - pass                                       низкопроходной

To oppose                                     оказывать сопротивление

On the other hand                                  с другой стороны

Choke coil                                      дроссельная катушка

Bypass co                                       шунтовая катушка

Bypass condenser                                 шунтирующий конденсатор

High - pass filter                                   фильтр верхних частот

Low - pass filter                                      фильтр низких частот

Opposing coils                                        противодействующие витки

Opposed current                                       противоток

 

ELECTRON TUBES

 

Цели: Введение и активизация в речи лексики по теме «Электронные лампы».

Оборудование: комплект тестов, раздаточный материал.

 

 

                             Vocabulary

I. Learn the words and expressions.

 

Tube                                                    электронная лампа

Bulb                                                         баллон

Grid                                                         сетка

Screen                                                       экран

To contain                                            вмещать

To collect                                             собирать

To emit                                                 излучать

To suppress                                          глушить, подавлять

Control circuit                                       контрольная цепь

Control grid                                         управляющая сетка

Screen grid                                          экранирующая сетка

Screen grid tube                                   экранированная лампа

Suppressor grid                                     защитная сетка

Counter flow                                        противоток

Oscillatory circuit                                 колебательный контур

 

 II. Read and translate the text.

 

Let us consider electron tubes. Among the electron tubes in use nowadays there are a diode, a triode, a tetrode and a pentode. The main parts of electron tubes are electrodes. Electrodes are placed into a glass or metal bulb.

A diode contains the cathode and the plate. When a diode operates the cathode emits electrons, the plate collects them.

A triode contains the cathode, the plate and the control grid. When the tube operates the cathode emits electrons, the plate collects them

and the grid controls the flow of electrons. Therefore, the grid is called a control grid.

A tetrode contains the cathode, the plate, the control grid and the screen grid.

When a tube operates it may oscillate. The function of the screen grid is to eliminate oscillations. Therefore it is called a screen grid.

A pentode contains two electrodes and three grids: the control grid, the screen grid and the suppressor grid. When a pentode operates the suppressor grid eliminates the secondary emission.

Common troubles in tubes are an open heater and low emission.

These troubles result from constant use or from some other reason. In case a tube has a trouble it stops operating or operates badly. A tube with a trouble should be replaced by another one.

 

VI. Make up the sentences.

1. tubes parts of The electrodes main electron are

2.  A the plate contains diode the and cathode.

3. of oscillations the function is to The screen grid eliminate.

4. is grid called Therefore it a screen

5. in tubes are troubles an open Common heater emission. and low

 

VII. Pair work. Think of five questions covering the article given below. Put these questions to your group mate and ask him/her to answer them.

 

When in an operating tube the screen-grid voltage is high, secondary emission does not return to the plate and passes to the screen grid. This re­sults in a counter flow of electrons. To eliminate this counter flow, a third grid was placed between the plate and the screen grid and connected to the cathode. This grid is called a suppressor grid. Since the suppressor grid has a negative potential it returns the secondary emission back to the plate and thus eliminates it in the tube. The tube containing electrodes - the cathode, the plate, the control grid, the screen grid and the suppressor grid - is called a pentode. The cathode emits electrons, the plate collects them, the control grid controls the flow of electrons, the screen grid helps the plate to collect electrons and reduces the capacity between the control grid and the plate, the suppressor grid eliminates the secondary emission.

VIII. Answer the following questions:

 

1.What types of electron tubes are used nowadays?

2.How many electrodes does a diode (a triode, a tetrode, a pentode) contain?

3.What is the function of the cathode (the plate, the control grid, the screen grid,            the suppressor grid)?

4.What does the constant use of a tube result in?

5.What does low emission result from?

6.When must a tube be replaced?

 

 

ПРАКТИЧЕСКАЯ РАБОТА № 14

                                  

 USE OF ELECTRON TUBES

 

 

Цели: Введение и активизация в речи лексики по теме «Использование электронных ламп».

Оборудование: комплект тестов, раздаточный материал.

 

                                         Vocabulary

I. Learn the words and expressions.

Half                                                               половина                           

To rectify                                                       выпрямлять

To amplify                                                     усиливать

To convert                                                     преобразовывать, обращать

By means of                                                  посредством, с помощью

That is why                                                    вот почему

To put into operation                                   приводить в действие, запускать

Half-Wave Rectifier

Alternating current is converted into direct current by means of a rectifier.

A half-wave rectifier consists of a diode in series with a resistance. In order to put a rectifier into operation, a source of a.c. should be applied to it. When an a.c. source is applied the diode begins to conduct. The rectifier passes currents during positive half-cycles of the applied voltage. That is why it is called a half-wave rectifier. When the device operates D.C. flows in the same direction. It is a pulsating current. Since pulsations should be eliminated, a filter is applied. Pulsations are elimi­nated by means of this filter.

 

ПРАКТИЧЕСКАЯ РАБОТА № 15

                            ELECTROMAGNETIC RELAY

Цели: Введение и активизация в речи лексики по теме «Электромагнитное реле».

Оборудование: комплект тестов, раздаточный материал.

 

                                   Vocabulary

I. Learn the words and expressions.

Spring Cross-section To close Close to To move To switch on To switch off Various II. Read and translate the text.

пружина поперечное сечение замыкать, закрывать близко к (от) двигать (ся), включать выключать различный, разнообразный

 

Electromagnetic devices called relays are widely used in various branches of industry.

The main parts of a relay are an electromagnet, a spring and an ar­mature. When a current starts flowing in the electromagnet winding, the armature moves and the spring closes the contacts. The primary circuit of a relay is its electromagnet circuit and the secondary circuit is the one closed by the contacts.

When there is nocurrent in the relay's primary circuit, the spring pulls the armature and the contacts open.

Shows how a relay is used to control the work of an electric motor. The relay is placed close to the motor which is connected to its secondary circuit. The armature closes the contacts of the secondary circuit, and the motor starts operating; it will stop when the relay opens.

Without a relay, conductors with a large cross-section would have to be brought to the motor. This would be very uneconomical. The current in a relay is tens and even thousands of times smaller than that used to power the motor. Therefore, the connecting wires can have small cross-sections.

  In many systems the relay primary circuit operates automatically. Every evening and morning street lights are switched on and off from the main control panel by means of a great number of relays

 

IV. Finish the sentences.

1. The main parts of a relay are…………

2. The primary circuit of a relay is………

3. Shows how a relay is used……..

4. The current in a relay is…………..

5. The current in a relay is………………

ПРАКТИЧЕСКАЯ РАБОТА № 16

                                           FUSES

 

 

Цели:  Введение и активизация в речи лексики по теме «Плавкие предохранители».

Оборудование: комплект тестов, раздаточный материал.

 

                                    Vocabulary

I. Learn the words and expressions.

Fuse Link Fault Faulty Equipment Installation To protect To utilize To equip To serve To melt Up to II. Read and translate the text.

плавкий предохранитель звено, связь дефект, неисправность неисправный оборудование установка; защищать, предохранять использовать оборудовать, снаряжать служить плавить вплоть до

Fuses are widely used nowadays as protection devices. They are utilized in various circuits, electrical equipment and installations..Fuses serve to protect them against over currents and short-circuits.

There are different types of fuses in use nowadays. Quartz-sand fuses serve for voltages up to 500 volts; fuses of this kind are pro­duced with current ratings of 15 to 60 amp and of 100 to 350 amp.

Fuses are commonly used in low-voltage industrial installations rated up to 1,000 V.

Fuse protection is based on a very simple principle: in case of a short-circuit or overcurrent, when the maximum value of current has been exceeded, the fusible link of a fuse is heated to its melting point. This opens the circuit and disconnects the circuit from the power source. In case of a fault, one should replace the faulty fusible element by a new one.

Fuses are used both in direct current and alternating current circuits.

 

 

IV. Finish the sentences.

 

1. Fuses are widely used………….

2. Fuses serve to………………….

3. Quartz-sand fuses serve………..

4. Fuses are commonly used………

5. Fuse protection is based on……..

6. Fuses are used both in…………..

VI. Make up the sentences.

1. devices used nowadays. Fuses are widely as protection

2. fuses in different nowadays types are of use There

3. is simple principle based Fuse very on a: protection

4. are used Fuses direct both in and current alternating current circuits.

5. This opens the circuit and the circuit disconnects the power from source.

 

VII. Complete the sentences using the correct variant:

 

1. A fuse serves                               a) as a load.

                                                         b) as a protection.

2. Fuses are used                            a) for d.c. only.

                                                         b) for both a.c. and d.c.

3. In case of a fault                         a) the whole fuse should be replaced.

                                                          b) the faulty link should be replaced.

4. Fuse protection is based on        a) a simple principle.

                                                          b) a complex principle.

VIII. Memorize the questions. Use them in a talk with your group mate:

 

1.What does a fuse serve for?

2.For what type of current are fuses used?

3.What should be done in case of a faulty fuse?

4.What principle is fuse protection based on?

                                       ПРАКТИЧЕСКАЯ РАБОТА № 17

                             

V. Finish the sentences.

1. The main components of any circuit are……

2. The most common power sources are………

3. Loads include………

4. Motors convert……….

5. Electric power is…......

 

VI. Make a dialogue.  

Say a few words about your electrical engineering laboratory. Say what power sources and what loads are utilized there. Have a talk with your group mate about their types and their operation.

VII. Answer these questions:

 

1.What are the main components of an electric circuit?

2.What is the function of an electric source?

3.What is the function of a load?

4.What is the function of wire conductors?

5. What other devices are utilized in a circuit

 

 

ПРАКТИЧЕСКАЯ РАБОТА № 18

PRACTICAL UNITS

Цель: Введение и активизация лексики по теме «Единицы измерения электричества».

Оборудование: комплект тестов, раздаточный материал, иллюстрации по теме.

 

Vocabulary

I. Learn the words and expressions.

 

Electrical (power)

The main unit

A current

A pressure

A voltage

A resistance

Flow

To form

To be measured

Electromotive force

To cause

To join

A cell

A circuit

A substance

To offer

The ohm

To represent

To connect

In succession

In series

In parallel

D.c. (direct current)

A.c. (alternating current)

An equation

To transform

To found

A product

A terminal

A value