Вариант задания студент выбирает по последней цифре присвоенного ему шифра. Контрольная работа за 4-й курс выбирается следующим образом: 1-й вариант – нечетная последняя цифра зачетной книжки, 2-й вариант – четная.

Контрольные работы для 2 курса

1 вариант.

1. Поставьте глагол to be или to have в соответствующей форме и времени:

1 His brother ...   three children.

2  Yesterday they ... breakfast at 9.

3 John ... in Moscow in 2000.

4 Her sister ... here tomorrow.

5 He always ... late for his lesson.

6 The cadets ... at their desks.

7 They ... at the concert last night.

8 Their children   ... good at maths.

9 I ... one child.

10 10) There ... some milk n the cup.

2. Напишите прилагательные в сравнительной и превосходной степени:

good, weak, short, large, comfortable, difficult, merry, happy, black, high.

3. Напишите в притяжательном падеже:

the bag of this man, the table of a teacher, cabins of these sailors, the words of our captain, the face of the woman.

4. Ответить на вопросы:

1) How old are you?

2) Have you got a mother?

3) Is she on pension?

4) What is your profession?

5) Where do you work?

6) What is your native town?

7) What country do you live in?

8) What countries does Russia boarder on in the West?

9) What minerals is the Russian Federation rich in?

10) What is the state structure of the Russian Federation?

5. Задайте общий и специальный вопросы к предложениям:

1) The rivers in the west are unsuitable for navigation.

2) Manhattan stands on rock.

3) About half million people work in the City.

6. Переведите на английский язык:

1) Кто будет руководить работой матросов?

2) Все курсанты будут усердно работать, чтобы овладеть будущей профессией.

3) Они могут управлять судном

4) Сердце города - Кремль и Красная площадь.

5) Фильм интересный, не так ли?

6) Я нигде не могу найти боцмана.

2 вариант.

1. Составьте предложения из предложенных ниже слов:

1 works, on, he, vessel, a .

2 many, books, they, English, have.

3 are, students, classroom, in, there, some, the

4 pen, is, the table, a, there, on.

5 who, many, has, English, got, books ?

2. Вставьте артикль, где это необходимо:

1 This is ... tree…. Tree is green.

2 I have ... bicycle. ... bicycle is black. My friend has no ... bicycle.

3 This is my ... table

4 I have two ... sisters.

3. Образуйте множественное число:

a man_r a boy, a box, a ship, a child, a foot, a name, a friend.                                                                                                                                          /

4. Замените подчеркнутые слова соответствующими притяжательными   местоимениями:

1) that woman's bag

2) the girl's pencil

3) these sailors' captain

4) the ship's cargo

5) his son's name

5. Задайте общий и специальный вопросы к предложениям:

1 There are some pictures on the wall.

2 I have eight lessons every day.

3 There are many ports in Russia.

6. Переведите предложения:

1 Познакомьтесь, это - Пит. Садитесь, пожалуйста.

2 У него мало английских книг.

3 Зеленая тетрадь находится на столе.

4 Матросы находятся на палубе.

5 Мы находимся на навигационном мостике.

6 Мой друг - моряк

7 Где сейчас капитан^?

8 В классе много парт.

7. Напишите числительные словами: Третий, девяносто два, тысяча, тринадцать, сорок шестой.

3 вариант.

1. Поставьте глагол to be или to have в соответствующей форме и времени:

1 His brother ...   three children.

2 Yesterday they ... breakfast at 9.

3 John ... in Moscow in 2000.

4 Her sister ... here tomorrow.

5 He always ... late for his lesson.

6 The cadets ... at their desks.

7 They ... at the concert last night.

8 Their children   ... good at maths.

9 I ... one child.

10)  There ... some milk n the cup.

2. Вставьте артикли, где это необходимо:

My ... sisters are students.

We have ... big dog.    ... dog is very clever.

3. Образуйте множественное число:

a woman, a tooth, a voyage, a city, a family, a book, a pencil, a vessel

4. Замените подчеркнутые слова соответствующими притяжательными местоимениями:

1) that woman's bag

2) the girl's pencil

3) these sailors captain

4) the ship's cargo

5) his son's name

5. Задайте общий и специальный вопросы к предложениям:

1) My father is a captain.

2) All our cadets study English well.

3) There is much rain and fog in winter.

6. Переведите предложения.

1) У нее много работы.

2) Не открывайте окон.

3) Каюта капитана очень большая

4) Давайте пойдем пешком.

5) Когда он завтракает?

6) Только немного рек пригодны для судоходства.

7) В чашке много воды.

8) Я живу недалеко от порта.

7. Напишите числительные словами: первый, третий, сорок два, семьдесят три, сто второй, двенадцатый

4 вариант.

1. Составьте предложения из предложенных ниже слов:

1 works, on, he, vessel, a .

2 many, books, they, English, have.

3 are, students, classroom, in, there, some, the

4 pen, is, the table, a, there, on.

5 who, many, has, English, got, books ?

2. Напишите прилагательные в сравнительной и превосходной степени

bad,, little, beautiful, tall, green, deep. warm, magnificent, interesting, gay.

3. Напишите в притяжательном падеже:

the book of my son. the games of that boys, the dresses of these girls, the new club of workers, the armchair of his grandmother.

4. Напишите вторую и третью формы глаголов:

do     be    write     invite     love

5. Задайте общий и специальный вопрос к предложениям:

1) Не will change the course soon.

2) There are two departments on board ship.

3) Moscow was founded in 1147

6. Переведите на английский язык предложения:

1) Все судоводители несут вахту на мостике.

2) Я буду проходить практику на учебном судне.

3) Когда капитан прикажет изменить курс?

4) Вчера в это время у нас был урок английского языка.

5) Московское метро было построено в 1935 году.

6) Его послали в машинное отделение 5 минут назад.

5 вариант.

1. Перевести слова: торопиться, выходной день, отсутствовать,  родной город, в море, смотреть на, тонкий, встречать, годовщина, тот.

2. Заменить выделенные слова соответствующими личными местоимениями.

1 Mike is at the English lesson now.

2 The Master is on the bridge.

3 Those pens are on the desks.

3. Перевести на английский язык.

1 Я курсант мореходного училища.

2 В нашей группе 15 студентов.

3 Кто сегодня отсутствует?

4 Мои часы спешат на 10 минут.

5 В нашем городе много музеев.

6 У меня мало друзей.

4. Вставьте глагол to be в нужной форме.

1) This ... a door.

2) These ... seamen.

3) ... the books on the shelf?

4) What colour ... the sea?

5) We ... students.

5. Напишите числительные словами.

Второй, тридцать четыре, одиннадцать, сто, восемьдесят седьмой.

6. Переведите: мало друзей, много воды, мало судов, много денег, мало масла.

7. Заменить выделенные существительные на местоимения в объектном падеже.

1) Tell Ann the time.

2) Give Nick and Alex the pens.

3) Look at the ship.

6 вариант.

1. Перевести слова: месяц, заниматься, присутствовать, стоять на вахте, болеть, промышленный центр, толстый, парус, полка, эти.

2. Заменить выделенные слова соответствующими личными местоимениями.

1) Give me the book please.

2) The girl is in the room.

3) The cadets are in the club.

3. Перевести на английский язык.

1) У меня мало свободного времени сегодня.

2) Мои часы отстают на 15 минут.

3) Кто сегодня дежурит?

4) В нашем классе 2 окна.

5) Мой друг сегодня отсутствует на занятиях.

6) В чашке мало воды.

4. Вставьте глагол to be в нужной форме.

1) ... he a cadet?

2) What ... those?

3) The decks ... clean.   

4) The ship ... at sea.

5) I ... not a captain

5. Напишите числительные словами.

Третий, девяносто два, тысяча, тринадцать, сорок восьмой.

6. Переведите: много денег, мало сахара, много домов, мало деревьев, много времени.

7. Заменить выделенные существительные на местоимения в объектном падеже.

1) Read my parents the letter.

2) Show Nick and me our note-book.

3) Look at the boy.

7 вариант.

1. Поставьте глагол to be или to have в соответствующей форме и времени:

1 His brother ...   three children.

2 Yesterday they ... breakfast at 9.

3 John ... in Moscow in 2000.

4 Her sister ... here tomorrow.

5 He always ... late for his lesson.

6 The cadets ... at their desks.

7 They ... at the concert last night.

8 Their children   ... good at maths.

9 I ... one child.

10) There ... some milk n the cup.

2. Вставьте артикли, где это необходимо:

My ... sisters are students.

We have ... big dog.    ... dog is very clever.

3. Напишите в притяжательном падеже:

the book of my son. the games of that boys, the dresses of these girls, the new club of workers, the armchair of his grandmother.

4. Напишите вторую и третью формы глаголов:

do     be    write     invite     love

5. Задайте общий и специальный вопрос к предложениям:

1 Не will change the course soon.

2 There are two departments on board ship.

3 Moscow was founded in 1147

6. Переведите на английский язык предложения:

1) Все судоводители несут вахту на мостике.

2) Я буду проходить практику на учебном судне.

3) Когда капитан прикажет изменить курс?

4) Вчера в это время у нас был урок английского языка.

5) Московское метро было построено в 1935 году.

6) Его послали в машинное отделение 5 минут назад.

8 вариант.

1. Вставьте глагол to be в нужной форме.

1 .. he a cadet?

2 What ... those?

3 The decks ... clean.   

4 The ship ... at sea.

5 I ... not a captain.

2. Напишите числительные словами.

Третий, девяносто два, тысяча, тринадцать, сорок восьмой.

3. Переведите: много денег, мало сахара, много домов, мало деревьев, много времени.

4. Замените выделенные слова соответствующими личными местоимениями.

1 Give me the book please.

2 The girl is in the room.

3 The cadets are in the club.

5. Перевести на английский язык.

1 Я курсант мореходного училища.

2 В нашей группе 15 студентов.

3 Кто сегодня отсутствует?

4 Мои часы спешат на 10 минут.

5 В нашем городе много музеев.

6 У меня мало друзей.

6. Написать прилагательные в сравнительной и превосходной степени

Bad, little, beautiful, tall, green, deep, warm, magnificent, interesting.

9 вариант

1. Поставьте глагол to be или to have в соответствующей форме и времени:

1 His brother ...   three children.

2 Yesterday they ... breakfast at 9.

3 John ... in Moscow in 2000.

4 Her sister ... here tomorrow.

5 He always ... late for his lesson.

6 The cadets ... at their desks.

7 They ... at the concert last night.

8 Their children   ... good at maths.

9 I ... one child.

10) There ... some milk n the cup.

2. Вставьте артикли, где это необходимо:

My ... sisters are students.

We have ... big dog.    ... dog is very clever.

3. Образуйте множественное число:

a woman, a tooth, a voyage, a city, a family, a book, a pencil, a vessel

4. Переведите предложения.

1) У нее много работы.

2) Не открывайте окон.

3) Каюта капитана очень большая

4) Давайте пойдем пешком.

5) Когда он завтракает?

6) Только немного рек пригодны для судоходства.

7) В чашке много воды.

8) Я живу недалеко от порта.

5. Напишите числительные словами.

Третий, девяносто два, тысяча, тринадцать, сорок восьмой.

6. Переведите: много денег, мало сахара, много домов, мало деревьев, много времени.

10 Вариант

1. Перевести слова: месяц, заниматься, присутствовать, стоять на вахте, болеть, промышленный центр, толстый, парус, полка, эти.

2. Заменить выделенные слова соответствующими личными местоимениями.

1 Give me the book please.

2 The girl is in the room.

3 The cadets are in the club.

3. Перевести на английский язык.

1 У меня мало свободного времени сегодня.

2 Мои часы отстают на 15 минут.

3 Кто сегодня дежурит?

4 В нашем классе 2 окна.

5 Мой друг сегодня отсутствует на занятиях.

6 В чашке мало воды.

4. Вставьте глагол to be в нужной форме.

1 ... he a cadet?

2 What ... those?

3 The decks ... clean.   

4 The ship ... at sea.

5 I ... not a captain.

5. Напишите числительные словами.

Третий, девяносто два, тысяча, тринадцать, сорок восьмой.

6. Переведите: много денег, мало сахара, много домов, мало деревьев, много времени.

Контрольные работы для 3 курса

1 вариант.

I. Перевести текст:

Elementary Generator Operation

If a conductor is moving parallel to a magnetic field, it does not cut through any lines of force, and no emf is generated in the conductor. This applies to the conductors of the loop at the instant they go through posi­tion A - no emf is induced in them, and therefore no current flows through the circuit. The ammeter registers zero.

As the loop continues rotating from position В (90 degrees) to position С (180 degrees) the conductors which are cutting through a maximum num­ber of lines of force at position В begin to cut through fewer and fewer lines until at position С they are moving parallel to the magnetic field and no longer cut through any lines of force. The induced emf will therefore de­crease as the loop moves from 90 to 180 degrees; and the current flow will also vary as the voltage varies.

II. Прочитайте и переведите слова и словосочетания:

1) Current flow, generator operation, action, initial position, direction, lines of force, assume, clockwise, registers, continues; 

2) Conductors moving parallel to, more and more lines of force,   in the same direction.

III. Выберите нужные словосочетания, чтобы закончить предложения:

1. At 90 degrees conductors are cutting...

2. As the loop is rotating from 90 degrees to 180 degrees the conductors begin to cut ...

Словосочетания:

Through  fewer and  fewer  lines  of  force; through a maximum  number of lines  of  force; in a clockwise  direction; parallel  to a magnetic  field.

IV. Просмотрите текст и расскажите, употребив данные словосочетания, о том что происходит:

conductor,  field, at nought degrees,  is moving parallel to, magnetic field, lines of force, armature loop, emf  , is rotating, ,is generated.

2 вариант

I. Перевести текст:

Elementary Generator Operation

As the loop rotates from position A to position B, the conductors are cutting through more and more lines of force, until at 90 degrees (position B) they are cutting through a maximum number of lines of force. In other words, between 0 and 90 degrees the induced emf in the conductors builds up from zero to a maximum value.

Here is the way the elementary generator works. Assume that the arma­ture loop is rotating in a clockwise direction and that its initial position is at A (nought degrees). At position A, the loop is perpendicular to the magnetic field, and the black and white conductors of the loop are moving parallel to a magnetic field. If a conductor is moving parallel to a magnetic field, it does not cut through any lines of force, and no emf is generated in the conductor.

II. Прочитайте и переведите слова и словосочетания:

1) current flow, generator operation, action, initial position,

direction, lines of force, assume, clockwise, registers, continues;

2) conductors moving parallel to,  more and more lines of force,   in the  same direction.

III. Выберите нужные словосочетания, чтобы закончить предложения:

1. Assume that armature loop is rotating...                                                                 

2. At nought degrees the black and   white conductors of the loop are moving...

Словосочетания:

Through  fewer and  fewer  lines  of  force; through a maximum  number of lines  of  force; in a clockwise  direction; parallel  to a magnetic  field.

IV. Просмотрите текст и расскажите, употребив данные словосочетания, о том что происходит:

conductor, clockwise direction, field, at nought degrees,  is moving parallel to,magnetic field, lines of force, armature loop, no emf, is rotating, ,is generated.

Вариант 3

I. Перевести текст:

D.C. Generator Construction and Operation

Armature Assembly: In practically all d.c. generators, the armature ro­tates between the poles of the field. The armature assembly is made up of a shaft, armature core, armature windings and commutator. The armature core is laminated, and is slotted to take the armature windings. The armature windings are usually wound in forms and then placed in the slots of the core.

The commutator is made up of copper segments insulated from one an­other and from the shaft by mica. Small slots are provided in the ends of the segments to which the armature windings are soldered. The shaft supports the entire armature assembly and rotates in the end bearings.

There is a small air gap between the armature and pole pieces to prevent rubbing the armature and pole pieces during rotation. This gap is kept to a rninimum in order to keep the field strength at a maximum.

Brushes: The brushes ride on the commutator, and carry the generated voltage to the load. They are usually made of a high grade of carbon, and are held in place by brush holders. A flexible braided conductor called a «pig­tail» connect each brush to the external circuit.

You have learnt that a current flow can be induced in a conductor when it cuts through a magnetic field.

II. Найдите в тексте эквиваленты следующих слов и словосочетаний:

якорное устройство, обмотка якоря, пазы сердечника, воз­душный зазор, высокая марка углерода, можно индуцировать, полезный ток, с низкой производительностью, это делают (достигают), один сплошной кусок, соединять с

III. Выберите нужный предлог - between, of, from, to, by:

1. The armature rotates ... the poles ... field.

2. The armature windings are usually wound in forms   and then placed in the slots ... the core.

3. The copper segments are insulated ... one another and ... the shaft ... mica.

4. There is a small air gap ... the armature and pole pieces.

5. The brushes carry the generated voltage ...  the load.

6. A flexible conductor connects each brush  ...  the external circuit.

IV. Напишите данные предложения, заменив  пассивную форму активной:

Образец:

The commutator is made up of copper segments.

Copper segments make up the commutator.

1. The generated voltage is carried to the load by brushes.

2. Each brush is connected to the external circuit by a flexible conductor.

3. Copper segments of the commutator are separated from one another and from the shaft by mica.

4. The brushes are held in place by brush holders.

5. The armature assembly is made up of the shaft, armature core, armature windings and commutator.

Вариант 4

I. Перевести текст:

Types of Armatures

Armatures used in d.c. generators are divided into two general types. These are the «ring» type armature and the «drum» type armature. The ring type armature was used in early designs of rotating electrical machinery, but today is seldom used.

The drum type armature is the standard armature construction today. The insulated coils are inserted into slots in the cylindrical armature core. The ends of the coils are then connected to each other at the front and back ends.

As a rule, most d.c. armatures use form-made coils. These coils are wound by machines with proper number of turns and to the proper shape. The entire coil is then wrapped in tape and inserted into the armature slots as one unit.

The coils are so inserted that the two legs of each coil are under unlike poles. In a two-pole machine, the legs of each coil are situated on opposite sides of the core, and therefore automatically come under opposite poles. In a four-pole machine, the legs of the coils are placed in slots (about one-quarter the distance) around the armature, thus again keeping the coils under unlike poles.

II. Найдите в тексте эквиваленты следующих слов и словосочетаний:

катушки, нужной формы, соседний коллектор, обмотка якоря, конечная ЭДС, равный, в этом случае, упрощенная схема

III. Заполните пропуски, выбрав нужный вариант:

1. Brushes having the   ...   polarity were connected together (different, same).

2. The ... of parallel paths through a lap winding was equal to the ... of poles (number, type).

3. The wave winding was used for ... applications (high-current, high voltage).

4. The winding passes under every pole before it ... to the pole from which is started (comes back, uses).

5. The entire coil is inserted into the armature ... (windings, slots).

6. The emf ... in a wave winding is equal to that induced in one-half of the total number of armature conductors (de­veloped, used).

IV. Переведите на английский язык слова второго собесед­ника в диалоге:

1. What types of armatures do you know?

2. Есть два типа якорей, применяемых в генераторах по­стоянного тока, - барабанный и кольцевой.

1. Is the ring type armature widely used today?

2. Насколько я знаю, этот тип применялся в ранних конст­рукциях вращающихся машин, но редко применяется сей­час.

1. And what type of armature is the standard armature con­struction today?

2. Это барабанный якорь.

Вариант 5

I. Перевести текст:

Types of D. C.Generators

Most practical d.c. generators have electromagnetic fields.Permanent-magnet fields are used only in very small generators  called magnetos ;so that, to produce a constant field for use in a generator, the field coils must be connected across a d.c. voltage  source. The d.c. current  in the field coils is called the «excitation current», and  may be supplied either from a separate d.c. voltage source, or by using the d. c. output of the generator itself.

If the field is supplied with current from an external source, the ge nerator is said to be «separately-excited”; but if some of the generator output  is used to supply the field current, it is said to be “self- excited”. In a self-excited generator the field coils may be connected either in series with the armature coils («series»), in parallel with the armature coils ( shunt), or partly in series and partly in parallel with the armature coils (compound).

Separately-excited d.c. generators have two circuits: the field circuit, consisting of the field coils connec ted  across a  separate  d.c. source,  and the arrmature circuit, consisting of the armature coil and the load resistance.

In a separately-excited d.c. generator, the field is independent of the armature,, since it is supplied with current from either another generator (exciter), an amplifier or a battery. The separately excited field provides a means of controlling the power output of the generator. With a slight change in the field current, a large change in the load current will result.

II. Дайте эквиваленты следующих слов и словосочетаний:

внешний источник, соединенный последовательно, возбудитель, средство, незначительное  возбуждение, генератор с самовозбуждением.

III. Выберите нужный предлог – with, of, in, by, from.

1. The field was supplied…current…an external force.

2. ...  a separately-excited d.c. generator, the field is independent ... the armature.

3. ...   a slight change…the field current, a large change… load current resulted.

4. ...   automatic motor control systems the field current is controlled... an amplifier

5. Permanent-magnet  fields are used only… very small generators.

IV. Замените инфинитивный оборот простым сказуемым:

1. Permanent-magnet fields are said to be used only in very small generators.

2. The field coils in a self-excited generator are known to be connected either in series with the armature coils, in paral­lel with them or partly in series and partly in parallel with the armature coils.

3. Separately-excited d.c. generators are know to have two circuits.

4. The separately-excited field is known to provide a means of controlling the power output of the generator.

Вариант 6

I. Перевести текст:

The Shunt D. С. Generator

A shunt d.c. generator has its field winding connected in shunt (or paral­lel) with the armature. Therefore the current through the field coils is deter­mined by the terminal voltage and the resistance of the field. The shunt field windings have a large number of turns, and therefore require a relatively small current to produce the necessary field flux.

When a shunt generator is started, the build-up time for rated terminal voltage at the brushes is very rapid, since field current flows even though the external circuit is open.

The illustration shows the schematic diagram and characteristic curve for the shunt generator. Observe that over the normal operating region of no load to full load (A—B), the drop in terminal voltage as the load current increases is relatively small. The shunt generator is therefore used where a practically constant voltage is desired, regardless of load changes. If the load current drawn from the generator increases beyond point B, the terminal voltage starts dropping off sharply. The generator should not be run beyond point B.

II. Дайте английский эквивалент:

часть выходной мощности генератора, весь ток якоря, относи­тельно мало витков, возбуждать, остаточный магнетизм, сила, нарастать, дальнейшее увеличение, точка насыщения, делает его полезным, требовать, резко.

III. Заполните пропуски:

1. Self-excited generators use part of… to supply excitation current to the field (current of an external source,   generator’s output)

2. The series field contains relatively…turns of wire (many,  few).

3. The amount of the emf…the strength of the residual  magnetism (produces, depends on)

4. With no load, no current can flow and therefore very… emf is induced (much, little)

5. When the load draws more current from the generator, this additional  current…the field strength (increases, uses).

IV. Вставьте нужный предлог- through, for, from, with, at, of, to:

1. ... a series generator the whole armature current flows… both the field and the load.

2. As the load draws more current…the generator, this additional current increases the field strength.

3. A shunt d.c. generator has its field winding connected… series ... the armature.

4. When a shunt generator is started, the build- up time… rated terminal voltage…the brushes is very rapid.

Вариант 7

I. Перевести текст:

A compound generator is a combined series and shunt generator. There are two sets of field coils — one in series with the armature , and one in parallel with the armature. One shunt coil and one series coil are always mounted on a common pole piece.

If the series field is connected so that its field aids the shunt field, the generator is called "cumulatively" compound. If the series field opposes the shunt field, the generator is called "differentially" compound.

Compound generators were designed to overcome the drop in terminal voltage which occurs in a shunt generator, when the load is increased. This voltage drop is undesirable where constant voltage loads such as lighting systems, are used. By adding the series field, which increases the strength of the total magnetic field when the load current is increased, the voltage drop due to the added current flowing through the armature resistance is over­come, and constant voltage output is practically attained.

The voltage characteristics of the cumulative compound generator depend on the ratio of the turns in the shunt and series field windings.

II. Дайте английский эквивалент:

комбинированный, всегда устанавливаются (монтируются), на­пряжение, на зажимах, падение напряжения, сила всего магнит­ного поля, соотношение витков в обмотках, постоянное напря­жение при всех нагрузках, напряжение при полной нагрузке (без нагрузки), в промежуточных точках, несколько выше, с увеличением, редко, быстро.

III. Заполните пропуски, выбрав нужный вариант:

A compound generator is a ... series and shunt generator (designed, combined).

This voltage ... is undesirable where constant voltage loads are used (drop, increase).

If the series windings are so proportioned that the terminal voltage is practically ... at all loads it is "flat-compounded" (different, constant).

An "over compounded" generator has its series fields so se­lected that the full-load voltage is ... than no-load voltage (greater, less).

The "undercompounded" machines are ... used (often, seldom).

IV. Задайте   вопросы, употребив вопросительное слово where:

1. One shunt coil and one series coil are always mounted on a  common pole piece.

2. Compound generators were designed to overcome the drop  of terminal voltage which occurs in a shunt generator when the load is increased.

3. In a differentially compounded generator the shunt and field coils are in opposition.

Контрольные работы для 4 курса

Вариант 1

I. Перевести текст:

Types of А. С. Motors

Since a major part of all electrical power generated is a. c, many mo­tors are designed for a. c. operation. A. C. motors can, in most cases, dupli­cate the operation of d. с motors and are less troublesome to operate.

A. C. motors are particularly well suited for constant-speed applications, since the speed is determined by the frequency of the a. c. applied to the motor terminals. A. C. motors are also made, however, which have variable speed characteristics within certain limits.

A. C. motors can be designed to operate from a single-phase a. c. sup­ply or from a multi-phase a. c. supply. Whether the motor is single-phase or multi-phase, it operates on the same principle. This principle is that the a. c. applied to the motor generates a rotating magnetic field, and this rotating magnetic field causes the rotor of the motor to turn.

A. C, motors are generally classified into two types: (1) the synchronous motor and (2) the induction motor. The synchronous motor is an alternator operated as a motor, in which a. c. is applied to the stator and d. с Is applied to the rotor. The induction motor differs from the synchronous mo­tor in that it does not have its rotor connected to any source of power.

II. Заполните пропуски, выбрав нужный вариант:

1. The speed is determined by the  ...  a.c. applied to the mo­tor terminals.

2. The synchronous motor is an ... operated as a motor, in which a.c. is applied to the ... and d.c. is applied to the ...

3. In the synchronous motor the rotor is synchronized with the set up by the stator.

4. The application of ......................   to the stator causes a rotating magnetic field around the rotor.

5. The strong rotating magnetic field exerts a strong  on the rotor.

three-phase ax., rotor, stator, frequency, rotating field, turning force, alternator

III. Найдите многокомпонентные определительные слово­сочетания и переведите предложения:

1. A.C. motors are well suited for constant-speed applications.

2. A.C. motors can be designed to operate from a multiphase a.c. supply.

3. The a.c. applied to the motor generates a rotating magnetic field.

4. The speed of rotating of the magnetic field depends on the frequency of the three-phase ax. supply.

5. The synchronous motors are used for loads which require constant speed from no-load right through to the full-load condition.

IV. Перевести предложения на английский язык:

1. Двигатели переменного тока более надежны в работе.

2. Скорость вращения магнитного поля зависит от часто­ты тока.

3. Ротор асинхронного двигателя - это цилиндр, состоя­щий из пластин.

Вариант 2

I. Переведите текст:

Induction Motors

The induction motor is the most commonly used a. c. motor because of its simplicity, its robust construction and its low manufacturing cost. These characteristics of the induction motor are due to the fact the rotor is a self-contained unit which is not connected to the external source of voltage. The induction motor derives its name from the fact that a. c. currents are induced in the rotor circuit by the rotating magnetic field in the stator.

The stator constructions of the induction motor and of the synchronous motor are almost identical, but their rotors are completely different. The in­duction motor rotor is a laminated cylinder with slots in its surface. The windings in these slots are one of two types. The most common is called a «squirrel-cage winding», which is made up of heavy copper bars connected together at either end by a metal ring made of copper or brass. No insulation is required between the core and the bars because of the very low voltage generated in the rotor bars. The air gap between the rotor and stator is kept very small so as to obtain maximum field strength.

The other type of winding contains coils placed in the rotor slots. The ro­tor is then called a «wound rotor».

II. Найдите многокомпонентные определительные слово­сочетания и переведите предложения:

1. The rotor is a self-contained unit.

2. A «squirrel-cage winding» is made up of heavy copper bars.

3. The rotor gets as close to the moving stator field as its weight and its load will allow.

4. The rotating magnetic field generated in the stator induces an emf in the rotor.

5. The induction motor is commonly used because of its robust construction and low manufacturing cost.

III. Заполните пропуски, выбрав нужный вариант:

1. A compound generator is a ... series and shunt generator (designed, combined).

2. This voltage ... is undesirable where constant voltage loads are used (drop, increase).

3. If the series windings are so proportioned that the terminal voltage is practically ... at all loads it is "flat-compounded" (different, constant).

4. An "overcompounded" generator has its series fields so se­lected that the full-load voltage is ... than no-load voltage (greater, less).

5. The "undercompounded" machines are ... used (often, seldom).

IV. Переведите предложения:

1. Ротор асинхронного двигателя не соединен с внешним источником питания.

2. Возникает вращающееся  магнитное поле, когда пере­менный ток подается на обмотку статора.

3. Трансформаторы используются для преобразования напряжения.