КОНТРОЛЬНАЯ РАБОТА № 3. 3.1. Общие указания к выполнению контрольной работы № 3

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3.1. Общие указания к выполнению контрольной работы № 3

Для выполнения контрольной работы №3 студенту необходимо изучить следующие грамматические разделы курса английского языка:

1. Пассивный залог видовременных форм Indefinite, Continuous, Perfect.

2. Грамматические функции и значения слов one, that, it.

3. Простые неличные формы глагола. Инфинитив в функции:

а) подлежащего;

б) обстоятельства цели;

в) составной части сказуемого;

г) определения.

4. Бессоюзное подчинение в определительных и дополнительных придаточных предложения.

Требования к выполнению и оформлению контрольной работы№3 остаются такие же, как и к контрольной работе №2.

3.2. Контрольные задания

Вариант № 1

Задание 1

Перепишите следующие предложения, определите в каждом из них видовременную форму и залог глагола сказуемого. Переведите предложения на русский язык.

1) At present the nature of electrification is being explained by the electron theory.

2) These synchronous motors have been made to operate from a single-phase power source.

3) In some newer machines this reversal will be accomplished using power electronic devices, for example, diode rectifiers.

4) The first source of continuous current was produced by Volta.

Задание 2

Перепишите следующие предложения и переведите их на русский язык, обращая внимание на разные значения слов that, one, it.

1) One should take into consideration that the energy sources of the world are decreased.

2) It is possible to carry out the repairs within the time.

3) This pull-push amplifier was introduced last year, and that one will be employed next four months.

4) One method of detecting the presence of a current in a wire is to measure the temperature rise in the wire.

Задание 3

Перепишите следующие предложения и переведите их на русский язык, обращая внимание на разные значения глаголов to be, to have, to do.

1) There is some force of attraction acting between the molecules of matter.

2) A two-winding transformer has two coils which have to be arranged so that the magnetic lines of force of one coil pass through the other one.

3) Both terminals of a generator are to be connected to the same pole of the current.

4) This material does not possess desired properties.

Задание 4

Перепишите следующие предложения и переведите их на русский язык, обращая внимание на бессоюзное подчинение.

1) Everybody knows this generator must operate continuously throughout the twenty four hours.

2) Solar power the scientists and engineers suggest to use is inexhaustible.

Задание 5

Перепишите следующие предложения и переведите их на русский язык, обращая внимание на функцию инфинитива.

1) To transmit a given amount of energy, less current is required at a high voltage than at a low voltage.

2) The circuit to be described will operate at high frequencies.

3) The magnetic flux is considered to be the result or effect due to the action of a magnetic force on a magnetizable body.

4) To simplify and make power generation cheaper the engineers will develop new type of energy generated installations.

Задание 6. Перепишите и письменно переведите первые 2 абзаца текста.

The Main Types of Transformers

Transformers may be classed according to the use they are designed for. Sometimes the transformer is used for operating a.c. ammeters, wattmeters and other measuring devices. Transformers may be used to make two electrical circuits electrically independent. But nearly all transformers come under one of the following classes: step-up and step-down transformers varying the ratio of turns between the primary and the secondary we can step up or step down the voltage. Some transformers are designed to raise the primary voltage to a higher value, such being known as step-up transformers. Others are constructed to reduce the primary voltage to a lower value, they are called step-down transformers.

A step-up transformer has more turns in the secondary than in its primary. In this type of transformer the current on the secondary side is lowered in the same ratio as the voltage is raised. In a step-down transformer there are fewer turns in the secondary than in its primary, the output voltage being smaller. In step-down transformers the current on the secondary side is raised in the same ratio as the voltage is lowered.

Transformers have many applications in a.c. circuits that require both the raising and lowering of the primary voltage аз well as the lowering and raising of the primary current.

There are transformers in which the number of turns in the secondary is the same as the number of turns in the primary. The secondary voltage is the same as the primary and this type of transformer is said to be a "one-to-one" transformer.

Transformers are widely applied in long-distance power transmission as well as in telephone, radio transmitters and receivers, television, electronic equipment. Transformers have a wide application on ships with different purposes. So as we have seen transformers are widely used in electrical engineering and they are of great importance.

Задание 7. Ответьте письменно на следующие вопросы:

1) What are transformers used for?

2) What are the main types of transformers?

3) According to what are transformers classed into step- up and step-down ones?

4) What is the main property of a step-down transformer?

5) What is а "one-to-one" transformer?

Вариант № 2

Задание 1

1) Transformers are being used to make two electrical circuits electrically independent.

2) The phenomenon which was discovered by Petrov was of the greatest importance.

3) Radioactive isotopes have been made in nuclear reactor.

4) The scientific researches will be followed by experimental work.

Задание 2

1) It is proved that the electricity transporting can't be without any power losses.

2) The specialists find out that all the harmful affects of it can be easily eliminated.

3) One has to choose the insulating material that will be the most efficient and cheapest one.

4) It is the movement of electrons which constitutes an electric current.

Задание 3

1) The heat of the Sun has been found to be the primary source of energy.

2) Current transformers are used whenever high voltage current has to be metered.

3) Specialists do not use solar cells in industry as they are too expensive.

4) Our plant is to increase the output of the electronic meters.

Задание 4

1) Electrical energy having escaped into free space exists in the form of electromagnetic waves.

2) You are to know the resistance passing through the conductor results in heat.

Задание 5

Перепишите следующие предложения и переведите их на русский язык, обращая внимание на функцию инфинитива.

1) The Instrument to be described here was designed some years ago.

2) To understand the operation of an ammeter is not difficult.

3) If the inductance in a circuit causes the rise and fall of current to produce a voltage in the same circuit, it is called self-inductance.

4) The function of a transformer is to convert eleсtrical energy from one сondition to another.

Задание 6. Перепишите и письменно переведите первые 2 абзаца текста.

Transporting electric Energy

As soon аs the electric energy is produced at the power station, it has to be transmitted over wires to the consumer. However, the longer the wire, the greater is its resistance to a current flow. On the other hand, the higher resistance, the greater are the heating losses in electric wires. It has been necessary to find ways of reducing energy losses in power transmission lines. The only solution to the problem of transmitting electric energy is to use high-voltage for long distances and low voltage for short ones. The transmission voltage being increased, the current required to carry the same power is correspondingly lower. The drop in voltage in the power lines is, thus, reduced.

The successful long-distance distribution of electric energy without great losses on the transmission line was made possible only due to the transformer and a.c. Let us see how it is made. As we know, one of the great advantages of a.c. is the ease and efficiency with which power at low voltage may be transformed into an almost similar amount of power at high voltage, and vice versa.

Since active power = volts x ampere x power factor, it will be evident that a large amount of power can be transmitted by over bend lines at high voltage with a small current. A small current requires a small size of conductor.

In a large power station, power may be generated at a voltage, say, 10,000 v. This voltage is raised by means of a transformer to 110,000 v. It is then transmitted to any place at which the power is required for use. At the place where power is needed, another transformer is employed to 3tep the voltage down to a value suitable for use in consuming devices, such аs 127 or 220 or 380 v.

So, as we see, in the transmission of electric energy over wires for long distances transformers are practically indispensable.

Задание 7. Ответьте письменно на следующие вопросы:

1) What is the relation between the length of wire and resistance?

2) What does high resistance result in?

3) Thanks to what can we transmit an electric energy without great losses?

4) What is the great advantage of a.c.?

5) What is the voltage of a current changed by?

Вариант № 3

Задание 1

1) The first electric lamp was invented by Lodygin.

2) DC generators are commonly classified according to the method used to provide field current for energizing the field magnet.

3) Two basic types of motors have been designed to operate on polyphase a.c.

4) The research of that d. c. generator will be developed by two groups of specialists.

Задание 2

Перепишите следующие предложения и переведите их на русский язык, обращая внимание на разные значения слов that, one, it.

1) It is necessary to obtain accurate data on power losses on this electricity transmission line.

2) One can see that a "one-to-one" transformer has the same number of turns in both windings.

3) It is the number of electrons within atom that determines the properties of a substance.

4) It was Einstein who came to conclusion that e.m.f. is influenced by the gravitation field.

Задание 3

1) While working with electricity transmission lines the engineers have to be careful.

2) The e.m.f. is at any instant proportional to the rate at which the magnetic flux is being changed.

3) Do we have to consider many quantities in the magnetic circuit?

4) A coil with many turns will have more inductance than that with few turns.

Задание 4

1) All the electrical equipment on board an electrician comes in contact with is to be familiar to him.

2) The current flowing in the circuit has a steady value.

Задание 5

Перепишите следующие предложения, и переведите их на русский язык, обращая внимание на функцию инфинитива.

1) The purpose of this chapter is to explain the difference between AC generators and DC ones.

2) No additional components were used since they were not needed to actuate the relay.

3) The distance to be covered was equal to ten miles.

4) To transform electric power into mechanical, heat and chemical power various installations were used.

Задание 6. Перепишите и письменно переведите первые 2 абзаца текста.

Generators

One of the main methods of producing electricity is electromagnetic method. Machines for the generation of electricity called generators require the use of some form of magnetism. A generator is a device which produces a current flow by electromagnetic induction. If a conductor moves through a steady field at angles to the lines of the magnetic flux, the conductor is out by them. This results in an e.m.f. to be induced in the conductor.

This is the fundamental arrangement for generation of electricity and is termed “electromagnetic induction". In this way electrical generators convert mechanical energy of rotation into electricity. Electrical generators operate on such a principle: a field is generated by a passing current through a field coil which is placed on the stator, or frame structure of the machine. A number of turns of wire are wound on the rotor, which is revolved within the field created by the stator, and an e.m.f. is induced in the wires.

If two connections are brought out through slip rings fastened to the rotor armature, and on which brushes are riding, an e.m.f. will be led to the brushes. When the brushes are attached to an electrical load, the current will flow, so electric energy is obtained from a generator.

The simple generator consists of one-turn coil or armature, moved by some mechanical device within the magnetic field, and in which an induced e.m.f. is produced; two magnetic poles producing the magnetic field; two slip rings and two brushes for leading off the e.m.f. induced.

Задание 7. Ответьте письменно на следующие вопросы:

1. What principle is used in operation of generators?

2. What is a generator?

3. When is an e.m.f. induced in a conductor?

4. What transformation does a generator perform?

5. What are the principal parts of the simple generator?

Вариант № 4

Задание 1

1) The field magnets mounted on the rotor are being excited by direct current.

2) When much had been done in the study of lasers by our university, it became an important scientific center.

3) The given material will be unaffected by any overload.

4) The experiments were repeated many times.

Задание 2

Перепишите следующие предложения и переведите их на русский язык, обращая
внимание на разные значения слов that, one, it.

1) The successes in the carried out experiments with this new opticoelectronic device made it possible to obtain a new reliable amplifier.

2) It is the energy of the falling water that is used to drive turbines.

3) One will have to develop new solar energy converter because the older ones are unsatisfactory.

4) It is necessary to find new sources of cheap energy.

Задание 3

1) In lifting the weight we have to do work against the force of gravity.

2) All molecules of a substance are to have the same average energy at any given temperature.

3) A current will pass through a resistor which is in parallel with a condenser, but the condenser will have no effect upon the circuit.

4) Did scientists have to create solar cells.

Задание 4

1) The facts you have been given above illustrate the wide use of transformers.

2) The transmission system we selected for everyday use is based on the combined activity of telecommunication and computers.

Задание 5

Перепишите следующие предложения и переведите их на русский язык, обращая внимание на функцию инфинитива.

1) The information they gave you helped to avoid the overload of motor.

2) When a condenser is connected to a source of a continuous e.m.f., the condenser takes sufficient charge to bring its plates to a difference of potential

3) To magnetize a body requires some energy.

4) The new engine is expected to meet the market needs for high efficiency, compactness and environmental requirements.

Задание 6. Перепишите и письменно переведите текст.

Power Quality

In recent years electricity has been used to power more sophisticated and technically complex manufacturing processes, computers and computer networks, and a variety of other high-technology consumer goods. These products and processes are sensitive not only to the continuity of power supply but also to the constancy of electrical frequency and voltage. Consequently, utilities are taking new measures to provide the necessary reliability and quality of electrical power, such as by providing additional electrical equipment to assure that the voltage and other characteristics of electrical power are constant.

Voltage regulation. Long transmission lines have considerable inductance and capacitance. When current flows through the line, inductance and capacitance have the effect of varying the voltage on the line as the current varies. Thus the supply voltage varies with the load. Several kinds of devices are used to overcome this undesirable variation in an operation called regulation of the voltage. The devices include induction regulators and three-phase synchronous motors (called synchronous condensers), both of which vary the effective amount of inductance and capacitance in the transmission circuit.

Задание 7. Ответьте письменно на следующие вопросы:

1. What is electricity used for?

2. What measures ate taken to provide the reliability of electrical power?

3. What happens when the current flows through the line?

4. What devices are used to regulate the voltage?

Вариант № 5

Задание 1

1) When a condenser is connected to a source of a continuous e.m.f., the

condenser takes sufficient charge to bring its plates to a difference of potential.

2) The subject of magnetism will be discussed in the next chapter.

3) The two halves of a commutator are being insulated from each other.

4) Both conductors and insulators have been widely employed in electrical engineering.

Задание 2

1) The efficiency of this electricity transmission line is larger than of that one.

2) In atomic power station one must get used to different detecting devices and sensors.

3) It is a problem to construct a coil which for a given voltage across the terminals will produce a given number of ampere turns.

4) We have already seen that a condenser consists of two insulated plates.

Задание 3

1) We have to connect the ammeter in series with the circuit when measuring current.

2) Having made all the necessary calculations, the engineer began to design a new machine.

3) Some substances do not conduct electricity.

4) Our laboratory is to carry out some experiments with laser beam.

Задание 4

1) We know the length of transmitting power lines varies from area to area.

2) The light-water reactor types we consider the most promising can replace the atomic power ones.

Задание 5

Перепишите следующие предложения и переведите их на русский язык, обращая внимание на функцию инфинитива.

1) This method of voltage control was the first to be used in connection with synchronous converters.

2) The pumps to be driven by the magneto-heat engine will give electricity to this district.

3) To achieve these aims only well-qualified electricians are good enough.

4) To meet industrial needs a.c. can be decreased or increased.

Задание 6. Перепишите и письменно переведите текст.

Electric Power Systems

Electric Power Systems are components that transform other types of energy into electrical energy and transmit this energy to a consumer. The production and transmission of electricity is relatively efficient and inexpensive, although unlike other forms of energy, electricity is not easily stored and thus must generally be used as it is being produced. A modern electric power system consists of six main components: 1) the power station, 2) a set of transformers to raise the generated power to the high voltages used on the transmission lines, 3) the transmission lines, 4) the substations at which the power is stepped down to the voltage on the distribution lines, 5) the distribution lines, and 6) the transformers that lower the distribution voltage to the level used by the consumer's equipment.

The power station of a power system consists of a prime mover, such as a turbine driven by water, steam, or combustion gases that operate a system of electric motors and generators. Most of the world's electric power is generated in steam plants driven by coal, oil, nuclear energy, or gas. A smaller percentage of the world's electric power is generated by hydroelectric (waterpower), diesel, and internal-combustion plants.

Задание 7. Ответьте письменно на следующие вопросы:

1. What are electric power systems?

2. What does a modern electric power system consist of?

3. What does a power station of a power system consist of?

4. Where is the electric power generated?

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