Metod_англ.мова_

There are two general methods by which a continuous supply of electrical charge is obtained; one being by means of a battery and the other being by means of an electric generator. The battery is known to be a device by which chemical energy is transformed into electrical energy and the generator as a device by which mechanical energy is transformed into electrical energy.

II Answer the following questions:

1.What is an electric current?

2.What does offer means of escape for the electrons?

3.What are general methods by which a continuous supply of electrical charge is obtained?

4.What kind of device is the battery?

5.What kind of device is the generator?

IV Choose the right variant from those given in brackets:

1.Computer ... a universal information processing machine. (are, is, been)

2.Bevel gears ... straight, skew and spiral teeth. (have, has, have to)

3.There ... a great number of couplings in current use. (is, are)

4.The frame ... the magnetic circuit of the field. (to complete, completes, have completed)

5.The word computer ... from a Latin word which means to count. (is coming, comes, to come)

6.The basic difference in two motors ... in the rotor winding. (to lie, lies, have lain)

7.Modern machinery ... of a large number of different parts. (consists, to consist, consist)

8.Electric drives often ... conversion equipment. (include, includes, to include)

9.Until the end of the last century, the main sources of motive power for machinery in industry ... steam and water. (to be, was, were)

10.The use of multimotor drive ... in modern industry. (is expanding, to be expanding, are expanding)

V Finish the following sentences according to the text:

1. ... as a flow of electric charges along a conductor.

2.This experiment is explained by ...

3.There are two general methods by ...

4. ... is known to be a device by which chemical energy ...

5. If this is not provided for, electrons will accumulate at the end of the wire, ...

6. ... it is spoken of as static electricity, but when it is in motion, ...

VI Give summary of the following text and be ready to speak on this topic.

Electric Generators and Motors

A device for converting mechanical energy into electric energy is called a generator. The function of a motor is just to reverse, that is, to transform electric energy into mechanical energy. The enormous energy of steam engines, gas engines and water turbines can now be transformed into electricity and transmitted many miles. The generator has revolutionized modern industry by furnishing cheap electricity.

The essential parts of a generator are:

a) the magnetic field, which is produced by permanent magnets or electromagnets; and b) a moving coil of capper wire, called the armature, wound on a drum.

D.C. generators are used for electrolytic processes. Large d.c. generators are used in certain manufacturing processes, such as steel making. Generators of small capacities are used for various special purposes, such as welding, automobile generators, train lighting communication system etc.

6

: ) I

Grammar: Tense Forms in Passive. Modals with Passive

I Read the text and translate it in writing.

Concept of the Electric Drive

An electric drive is defined as a form of machine equipment designed to convert electric energy into mechanical energy and provide electrical control of this process.

The fundamental elements of an electric drive are the electric motor, the transmission, and the electrical control system. Electric drives often include conversion equipment to make the motor operate on specific speed-torque characteristics.

The main function of the electric drive, is the imparting of motion to the working machine. However, a modern electric drive with a system of automatic control fulfills several other functions so as to carry out the production process involved in the most

efficient manner. The development of different kinds of electric drives used in industry may be divided into three stages: the group, individual and multimotor drive stages.

By group electric drive is meant a drive in which a single electric motor drives a line shaft by means of which an entire group of working machines may be operated. It is also sometimes called line shaft drive. This form of drive is practically never used in modern drive practice, it being only of historical interest. Today use is made of individual and multimotor drives.

An individual electric drive uses a single electric motor to drive one individual machine. Examples of such drive are single-spindle drilling machines, various kinds of electrical hand tools, and simple kinds of metal-working machine tools and mechanisms. In many cases such a drive uses an electric motor specially designed to be an integral part of the mechanism it serves to drive.

Multimotor drive is the term applied to a drive consisting of several individual drives each of which serves to operate one of many working members or mechanisms in some production unit. Such drive is required by complicated metal-cutting machine tools, paper-making machines, rolling mills, and similar types of machinery. The use of multimotor drive is continuously expanding in modern industry.

II Answer the following questions:

1.What is an electric drive?

2.What are the fundamental elements of an electric drive?

3.What is the main function of the electric drive?

4.What may the development of different kinds of electric drives be divided?

5.What does use an individual electric drive?

IV Choose the right variant from those given in brackets:

1.The beginning and end of current limiting action ... on the current-time curve. (is represented, are represented, to be represented).

2.Stator coils in alternators ... well braced. (must be, not must be, ought)

3.Water ... from rivers, lakes or seas to be used in factories and power plants. (is taken, are taken, to be taken)

4.Computer in chemical plants, power stations. (is used, are used, used)

5.They ... how to solve this problem on a computer. (were explained, was explained, to be explained)

6.The first programmer computer which operated successfully ... in 1939. (was built, is built, were built)

7.Your scientific article ... by the end of the year. (will be published, will publish, not will be published).

8.As lathes in general .. for great variety of operations, there are many different designs and size. (are used, is used, used)

9.The bench lathe ... to small work. (is adapted, are adapted, be adapted)

10.All machines ... of parts and units.

V Finish the following sentences according to the text:

1. This form of drive ...

2. ... uses a single electric motor to drive one individual machine.

3. The use of multimotor drive is ...

4. ... is meant a drive in which a single electric motor drives a line shaft ...

5.However, a modern electric drive with a system ...

6.The fundamental elements of an electric drive are ...

VI Give summary of the following text and be ready to speak on this topic.

Electric Motors

There is a wide variety of d.c. and a.c. motors. There are shunt motors, series motors, synchronous motors, induction motors, single - two and three-phase motors. They are used to drive various machines.

Direct-current motors are of three principal kinds, and are named according to the manner in which their field coils are connected to the armature. They are named respectively: series, shunt, and compound.

In the series motors the field windings and armature are connected in series with each other. All the current which passes through the armature passes through the field coils. The field windings are therefore composed of a few turns of thick wire. Starting under heavy load a series motor will take a large current to provide the torque required.

The field coils of shunt motors are connected direct across the brushes, hence they have the full votage of the mains applied to them. The shunt motor may be called a constant speed motor, and is suitable for driving machine tools, lathes, woodworking machines and any machines requiring a steady speed.

A compound motor has both shunt and series field windings and therefore partakes of the nature of both types of motors.

6

: ) II

Grammar: Tense Forms in Passive. Modals with Passive (Review)

I Read the text and translate it in writing.

Condensers and Dielectric Materials

The dielectric of a condenser is one of the three essential parts. It may be found in solid, liquid, or gaseous form or in combinations of these forms in s given condenser.

The simplest form of a condenser consists of two electrodes or plates separated by air, this representing a condenser having a gaseous dielectric. If this imaginary condenser had the air between the plates replaced by a nonconducting liquid, such as transformer oil, and if the distance between the plates were the same as in the first case, the capacitance would be found to have increased several times on account of the oil having a higher value of dielectric constant than air which is usually taken as 1.

The space between the plates being occupied by a solid insulator, a condenser would result, which would be practical, as far as the possibility of constructing it is concerned. It would be found, in this case too, that the capacitance of the condenser was several times larger than when air was the dielectric.

The mechanical construction of either air or liquid dielectric condensers requires the use of a certain amount of solid dielectric for holding the two sets of plates.

There are a great many dielectric or insulating materials available from which one may choose. A material which is very good from the electric standpoint is often found to be poor mechanically or vice versa, air being the gas generally used as a dielectric. Compressed air has been used in some high-voltage condensers, compressed nitrogen and carbon oxide being also in use.

Several kinds of oil have been used in condensers, such as castor oil, cottonseed oil, and transformer oil.

II Answer the following questions:

1.Where may some forms of dielectric find?

2.What is the simplest form of a condencer?

3.When was the capacitance of the condenser larger than air?

4.Where is compressed air used?

5.Where are several kinds of oil used?

IV Choose the right variant from those given in brackets:

1.Pollutants ... into several different classes. (can be separated, not be separated, can not be separated)

2.A magnetic field ... between the north pole and the south pole (are established, is established, to be established).

3.The wound-rotor motor ... in cranes, elevators. (are used, is used, used)

4.The rotating part of the generator ... the rotor. (are called, is called, to be called)

5.Compound generators ... differentially. (can be connected, not be connected, can not be connected)

6.The shunt dc generator ... constant-potential generator. (can be called, can not be called, not be called)

7.The commutator bars ... from each other. (are insulated, is insulated, to be insulated)

8.The bearing housing ... of cast iron. (are made, is made, made)

9.A human tells the machine what to do, when to do it and how it ... (should be done, should not be done, not be done)

10.Every engineer ... know the properties of engineering materials. (had, could, should)

V Finish the following sentences according to the text:

1. ... is one of the three essential parts.

2.The space between the plates ...

3.The mechanical construction of either air or liquid ...

4.There are a great many ...

5.Compressed air has been used ...

6. ... used in condensers, such as ...

VI Give summary of the following text and be ready to speak on this topic.

"A.C. Electric Motors".

Motors for alternating - current circuits way be either single-phase or polyphase (two - or three-phase). They may again be divided into two kinds, named respectively: 1. Synchronous; 2. Non - or asynchronous, ordinarily called induction motors. The most widely used a.c. motor is the induction motor. It has two main parts:

a) the stationary winding or stator, which sets up a rotating magnetic field, and b) the rotating part of the motor, i.e. the rotor. The rotor of a commercial a.c. motor consists of an iron core with large copper bars placed in slots around the circumference and connected at both ends to copper rings. This is called a squirrel-cage rotor. When a rotor is placed in a rotating magnetic field, a large current is induced in it.

A.c. motors are exactly similar in construction to a.c. generators and may be called inverted alternators, since the same machine may be used as either a generator or a motor.

Synchronous motors are very suitable for large powers, where the machine can be started up without load, and once started run for long periods.

For supplying direct-current power networks, the supply comes first from an alternating-currant source and is converted to direct current by synchronous converters or motor-generator sets.

5

: )

Grammar: Tense forms in Active. Participles (Review).

I Read the text and make the written translation of it.

What is a computer?

Computers are electronic machines, which can accept data in a certain form, process the data and give the results of the processing in a specified format as information.

Three basic steps are involved in the process. First, data is fed into the computer's memory. Then, when the program is run, the computer performs a set of instructions and processes the data. Finally, we can see the results (the output) on the screen or in printed form.

Information in the form of data and programs is known as software. A set of instructions telling a computer what to do is a program. Programs are usually written in programming languages like Pascal, C++, etc they are organized into files. Applications are programs for specific tasks. Applications include: database soft, spreadsheets calculations, word-processing on a word processor. The electronic and mechanical parts that make up a computer system are called hardware. To function hardware and software, a computer needs an operation system program.

Some operation systems require users to type commands to tell the computer what to do. Many computers use a graphical interface or point-and-click interface such as Windows. Some interfaces allow plug-and-play, the possibility of connecting new hardware of the computer without having to adjust or configure the system to take the new hardware into account: the interface program recognized the hardware automatically.

A standard computer system consists of three main sections: the central processing unit (CPU), the main memory and the peripherals.

Perhaps the most influential component is the central processing unit. Its function is to execute program instructions and coordinate the activities of all other units. In a way, it is the 'brain' of the computer. The main memory holds the instructions and data

which are currently being processed by the CPU. The peripherals are the physical units attached to the computer. They include storage devices and input/output devices.

Storage devices (floppy, hard or optical disks) provide a permanent storage of both data and programs. Disk drives are used to handle one or more floppy disks. Input devices enable data to go into the computer’s memory. The most common input devices are the mouse and the keyboard. Output devices enable us to extract the finished product from the system. For example, the computer shows the output on the monitor or prints the results onto paper by means of a printer.

On the rear panel of the computer there are several ports into which we can plug a wide range of peripherals – modems, fax machines, optical drives and scanners.

There are the main physical units of a computer system, generally known as the configuration.

II Answer the following questions:

1.What are the basic steps of the processing the data?

2.What is software?

3.What is hardware?

4.What is the function of the CPU?

5.What storage devices do you know?

III Match the following words and word-combinations. Learn them by heart.

IV Choose the right form and translate the sentences.

1. Ten years ago vast improvements in the size, speed and capabilities of computers …. a) to take place b) took place c) were taken place

2.From the first electronic digital computers of the forties to today’s versatile computers very little … .

7.In some years new supercomputers … from usual computers in additional processors and hard disks.

VI Give the summary of the text and be ready to speak on the topic.

Types of printers

Printing is the final stage in creating a document. That is the purpose of the printers joined to your computing equipment. Since the results you can obtain with different types of printers will vary substantially, here is a guide to help you decide which one is most suitable for you needs.

To begin with, it must be taken into account that printers vary in cost, speed, print quality and other factors such as noise or compatibility. In fact, printing technology is evolving so quickly that there is always a printer for every application or personal requirement.

Dot-matrix printers use pins to print the dots required to shape a character. They print text and graphics and nowadays some of them can print up to 500 characters per second (cps); however, they produce relatively low resolution output - 72 or 144 dots per inch. They are slower than laser printers hut much cheaper.

One common type of non-impact printer is an ink-jet printer. It operates by projecting small ink droplets onto paper to form the required image. This type of printer is quite fast, silent and not so expensive as a laser printer. Nevertheless, you can expect high quality results because there are some ink-jet printers on the market win a resolution of 720 dpi. Bubble-Jet printers work the same way

Laser printers produce output at great speed and with a very high resolution of 600/2,400 dpi. They scan the image with a laser beam and transfer it to paper with a special ink powder. They are constantly being improved. In terms of speed and image quality they are preferred by experts for different reasons: they have a

wider range of scalable fonts, they can emulate different language systems, they can produce graphics, and they have many other advantages. It goes without saying that they are still expensive for home users.

We must not forget to mention thermal printers. They use heat, a special kind of paper and electrosensitive methods. They are silent and considered to be inexpensive. However, some colour models that emulate HP (Hewlett Packard) plotters cost too much to be included in the same category.

Imagesetters can be regarded as an attractive alternative. They produce very highresolution output (up to 3,540 dpi) on paper or microfilm. In addition, they are extremely fast. They are used in desktop publishing. Although they produce the highest quality output, they have one important drawback: they are too expensive for homes or small offices.

Finally, plotters are a special kind of printer. Plotters use ink and fine pens held in a carriage to draw very detailed designs on paper. They are used for construction plans, engineering drawings and other technical illustrations.

5

: )I

Grammar: Tense forms in Active. Participles (Review).

I Read the text and make the written translation of it. The computer

Every computer contains five essential elements or units: the arithmetic logical unit, the memory unit, the control unit, the input unit, and the output unit.

The arithmetic logic unit is the area of the computer in which arithmetic and logical operations are performed on data.

The memory unit stores groups of binary digits (words) that can represent instructions (programme) which the computer is to perform and the data that is to be operated on by the programme.

The input unit consists of all me devices used to take information and data that are external to the computer and put it into the memory unit.

The output unit consists of the devices used to transfer data and information from the computer to the outside world.

The control unit directs the operation of all the other units by providing timing and control signals. This unit contains logic and timing circuits that generate the signal necessary to execute each instruction in a programme.

The parts of a computer you can touch, such as the monitor or the Central Processing Unit (CPU) are hardware. All hardware except the CPU and the working memory are called peripherals. Computer programs are software. The operating system