ENGLISH FOR ELECTRICAL ENGINEERING
DRW - STTH
ELECTRICAL CONDUCTOR
Electrical conductor is any material that offers little resistance to the flow of an electric current. The difference between a conductor and an insulator, which is a poor conductor of electricity or heat, is one of degree rather than kind, because all substances conduct electricity to some extent. A good conductor of electricity, such as silver or copper, may have conductivity a billion or more times as great as the conductivity of a good insulator, such as
glass
or
mica.
superconductivity
is
A
phenomenon observed
known
when
as
certain
substances are cooled to a point near absolute zero, at which point their conductivity becomes almost infinite. In solid conductors the electric current is carried by the movement of electrons; in solutions and gases, the electric current is carried by ions. Exercise 1. Property of any object or substance to resist or oppose the flow of an electrical current is called ______________1. 2. Phenomenon displayed by certain substances that conduct electricity but demonstrate no resistance to the flow of an electric current is called ____________2. ____________2. 3. _____________ 3. _____________ is the lowest temperature theoretically theoretically possible, characterized characterized by complete absence of heat (thermal energy). 4. __________, in chemistry, chemistry, are homogeneous homogeneous (uniform) (uniform) mixtures mixtures of two or more substances.
ELECTRIC INSULATION
The perfect insulator for electrica e lectricall applications would be a material that is absolutely nonconducting; such a material does not exist. The materials used as insulators, although they do conduct some electricity, have a resistance to the flow of electric current as much as 2.5 × 1024 greater than that of good electrical conductors such as silver and copper. Materials that are good conductors have a large number of free electrons (electrons not tightly bound to atoms) available to carry the current; good insulators have few such electrons. Some materials such as silicon and germanium, which have a limited number of free electrons, are semiconductors and form the basic material of transistors. In ordinary electric wiring, plastics are commonly used as insulating sheathing for the wire itself. Very fine wire, such as that used for the winding of coils and transformers, may be insulated with a thin coat of enamel. The internal insulation of electric equipment may be made of mica or glass fibers with a plastic binder. Electronic equipment and transformers may also use a special electrical grade of paper. High-voltage power lines are insulated with units made of porcelain or other ceramic, or of glass. The specific choice of an insulation material is usually determined by its application. Polyethylene and polystyrene are used in high-frequency applications, and mylar is used for electrical capacitors. Insulators must also be selected according to the maximum temperature they will encounter. Teflon is used in the high-temperature high-temperature range of 175° to 230° C (350° to 450° F). Adverse mechanical or chemical conditions may call for other materials. Nylon has excellent abrasion resistance, and neoprene, silicone rubber, epoxy polyesters, and polyurethanes can provide protection against chemicals and moisture.
Exercise 1. What would a perfect insulator be like? 2. What characterizes good insulators? 3. What materials are used as insulating sheathing for wire? 4. What materials are used for insulation of electronic equipment? 5. What determines the choice of an insulation material? Exercise Find out the similar meanings from the text 1. Complete
=
2. Positively
=
3. Live
=
4. Fundamental
=
5. Seperated
=
6. Particular
=
7. Choose
=
8. Meet
=
9. Substantial
=
10. Supply
=
SIMPLE PAST TENSE VS PAST CONTINUOUS
Simple past tense
We use the simple past to describe things that happened in the past and finished at a specific time. Example: He started the company in 1969. They didn’t make a profit in the first year. Did she work there in 1975?
We often use a time reference which refers to the finished event. E.g. yesterday, last week, last night, three years ago, in 1969, in the first year.
Form
verb stem + ed Positive and Negative I/ you/ she/ he/ it/ we/ they
Arrived
Didn’t arrive
Question Did
I/ you/ she/ he/ it/ we/ they
Arrive?
The verb to be
Positive and Negative I/ he/ she
Was
Was not/ wasn’t
You/ they/ we
Were
Were not/ weren’t
Past continuous Use
________ Was/Were + V(ing)
We use the past continuous to talk about: Things which which were happening happening at the time of speaking. Example: I was trying to call Geoff Peters. He was n’t n’t working today.
Exercise Change these sentences into positive, negative or introgative sentences 1. We controled the temperature regularly 2. Did he explain the classification classification of conductor? 3. The current current didn’t flow from positive positive terminal to negative terminal 4. They calculated calculated the energy unit 5. They didn’t use a tester tester to current supply in electrical electrical circuits circuits
Exercise MICROSOFT
Thomas (live) in the small town of Brington. He (love) walking through the beautiful forest that surrounded it. One evening, it (rain) , so he (take) his umbrella and (go) for a walk in the woods. As he (walk) through the woods, he (meet) an old man named Frank. Frank (tell) Thomas that if he (want) to become rich, he should invest in a little known stock called Microsoft. When Thomas (return) from his walk, he (think) Frank (be) foolish because Microsoft (be) a computer stock. Everybody (know) that computers (be) just a passing fad. At any rate, Frank (insist) that Thomas (be) wrong. While they (discuss) the stock, Frank (draw) a wonderful graph of future possibilities. As Frank (draw) the graph, Thomas (begin) (begin) thinking that maybe maybe Frank (understand) (understand) stocks. stocks. While he (was) to work, Thomas (decide) to buy some of these stocks. The next day, he (go) to the stock broker's and (buy) $1,000 worth of Microsoft stock. That (be) in 1986; today that $1,000 worth of stock is worth more than.
NUMBERS
I. Match the words with the examples on the right:
1. cardinal numbers
a. ¼, 2/3, 28/36
2. ordinal numbers
b. First, second, third, ...
3. decimals
c. 1, 2, 3, …
4. fractions
d. 12%, 89%...
5. percentages
e. 2.3, 4.698
* Each digit after the decimal point is read separately: two point three, four point six nine eight. II. Match these written numbers with the way they are read:
1. 60%
a. one third
2. 3 ½
b. two fifths
3. 3.4
c. two point eight seven
4. 8.5%
d. eight point five percent
5. 1/3
e. three point four
6. 2.87
f. sixty percent
7. 3/4
g. three and a half
8. 2/5
h. three quarters
III. Put these words and phrases into the sentences below: times/multiplied by, divided by, minus, plus
1. Four________ eighteen equals twenty-two. 2. Seventeen ____________ thirteen equals two hundred twenty-one. 3. Ninety-six _________ four equals twenty-four. 4. Ten ________ nine equals one.
THE EFFECTS OF AN ELECTRIC CURRENT
The effects of an electric current are thermal, luminous, chemical chemical and magnetic. When a current flows through a conductor it may heat the conductor. This heat is sometimes undesirable undesirable and has to be reduced. For this reason many electric motors and generators contain a fan. However, domestic appliances, such as electric cookers, and many industrial processes depend on the heating effect of an electric current. The passage of a current may produce light. This can happen in a number of ways. The heat generated by the current may be so great that the conductor becomes incandescent. For example, the filament of a light bulb emits intense white light when heated by a current. Light is also produced when a current ionises a gas. The colour of the light will vary according to the gas used. Mercury vapour lamps give a greenish-blue light. An electric current can separate a chemical compound into its components. This is called electrolysis. Chlorine is generated by the electrolysis of salt water. Electrolysis can also be used to break down water into hydrogen and oxygen. Because pure water does not conduct well, sulphuric acid has to be added before the electrolysis takes place. A current flowing through a conductor creates a magnetic field around it. This field has three applications. applications. It can magnetize magnetic materials and attract them to the conductor. The electric relay works on this principle. If the magnetic field is cut by another conductor, an electromotive force will be induced in that conductor. For instance, the change in current flowing through the primary of a transformer will induce a current in the secondary. This principle is also used in generators. Thirdly, if a current carrying conductor is placed in the magnetic field, a force will e exerted on it. This effect is utilized in the electric motor.
Exercise:
Now study the passage carefully and complete this framework of notes: Effects of an electric current:
1. Thermal 2. ……………. 3. …………….
4. Magnetic 1. Heat can be a. Undesirable, e.g. motor b. ……....... e.g. cooker
2. light a. from incandescent con ductor e.g. ….....…….. b. from ….....….. e.g. vapour lamp
3. ……....... = breakdown of chemical compound e.g. salt water into chlorine
4. current flowing in conductor ► ….....… round it. Magnetic field has three
applications: a. ……....... e.g. relay b. induce emf in another conductor e.g. …….....….. c. …….....… e.g. motor
HAND TOOLS AND THEIR USES
Nowadays, the speed and productivity are very important, and therefore many works in the workshop are being done with the power tools and machines. However, any good craftsman knows that the quality result lies in the balance between the handwork and machine work. In many cases during the manufacture, the craftsman has to decide whether some operation will be done with the hand tools or with the machine. Such decision should always be made by considering which method is more efficient, which method you are adept to, which
methods
produce
better
work
and
which
method
is
cheaper.
Always use right hand tool for the job. This way you get the best job with the least effort, the least damage to the tool and the least danger to yourself. In some cases, hand tools are faster than the machines. Of course, if many identical parts need to be cut, hand tools are definitely slower. But if you work on some unique project, it will surely be easier to perform some operations with the hand tools, rather than to waste time to set up and configure your machine. One of the important advantages of hand tools is that they are cheaper than the power tools, so if in your work you do not have a specific need for this type of tools, it will be much more cost-effective to buy less expensive hand tool and use it occasionally, than to buy an expensive power tool which will lay on the shelf. Besides that, the hand tools are indispensable for the house maintenance. Various jobs on the house are occasional, so it is not profitable to invest a lot of money in various power tools. Another great advantage of hand tools is that they are much safer than the power tools, and this is important for both craftsmen beginners and for the amateurs, who use hand tools just for quick repairs.
Exercise Hand tools can be divided into several groups:
Laying out tools – Measuring Measuring and marking tools
Impact or striking tools (hammers, mallets and sledges)
Twisting tools tools or fastening fastening tools (wrenches (wrenches and and screwdrivers) screwdrivers)
Woodcutting tools (wood saws, planes, wood chisels)
Metal cutting tools (dies, drills, files, punches, reamers, taps)
Holding tools (clamps, pliers, vises)
Safety equipment (goggles, gloves)
Grinding and sharpening tools
Finishing tools and abrasives
Tool storage storage & accessory accessory containers containers
PASSIVE VOICE
A.
The form of Passive Voice
Passive voice is the We form the passive voice in English with the verb to be as an auxiliary, plus the past participle of the main verb. For every active voice in English there is a corresponding passive voice. Formation
Exercise Change these sentences into passive voice 1.
You must leave the message The message message must be left by you
2.
The maintenance department regularly services the machine. ……………………………………………
3.
You should wear protective clothing in the workshop …………………………………………….
4.
The mechanic wrote a report concerning the failure ………………………………………………
5.
The mechanic is checking instrument for measuring …………………………………
6.
we will clean the workshop soon ………………………………
7.
He bought a new fork lift for the factory ………………………………
8.
You can improve your mechanical engineering knowledge by practicing. ……………………………………
9.
The lecturer has devided material into two main classes ………………………………….
10.
Office workers will use Electrician’s Safety Tools
Exercise Describe the operation of the new speed trap by converting each of these statements to the Present Passive.
1. The first unit records the time each vehicle passes. 2. It identifies each vehicle by its number plates using Optical Character Recognition
(OCR) software. 3. It relays the information to the second unit. 4. The second unit also records the time each vehicle passes. 5. The microprocessor calculates the time taken to travel between the units. 6. It relays the registration numbers on speeding vehicles to police headquarters. 7. A computer matches each vehicle with the Driver and Vehicle Licensing Centre (DVLC) database. 8. It prints off a letter to the vehicle owners using mailmerge
APPLICATION LETTER
Application letter is also called by A cover letter. Application letter is a document sent with your resume to provide additional information on your skills and experience. Business and professional people are hired on the basis of application letter and interview General points:
• Keep it brief • Begin your letter or email ‘Dear Mr / Mrs/ Msxxxx’ if you know the person’s name, or ‘Dear Sir or Madam’ if you don’t know their name.
paragraphs. • Short paragraphs. • Check your spelling, grammar, and
punctuation carefully. Part of Application Letter
1. Heading a. Sender's address: b. Date 2. Inside Address This is the address address you are sending sending your letter letter to (the company’s company’s address). address).
Make it as complete as possible. Include titles and names if you know them 3. Salutation Example: Dear Sir, 4. Body The body of a good application letter, usually 3 to 4 paragraphs, paragraphs, explains why the applicant is a good fit for the job, explains relevant experience, and shows how that experience would be useful if selected for the career opportunity. 5. Closing Example: Yours sincerely, 6. Signature Do not followed by punctuation Consist of application letter
1. Introduction 2. Statement of qualification qualification 3. Reason for applying the job
4. Availability of the applicant 666 Antares Way Ray, MA 02072 Januari 15, 2016 Ms. Nancy Mary Human Resources Manager McKeith & Company, Inc. Parkinson Park Plaza, dome 2000 Boston, MA 02101 Dear Ms. Mary, Application for the position of product designer In reference to the job vacancies you advertised at the Carpenters’ Industrial College career caree r bazaar, I would like li ke to apply for the position of product designer. I believe that while I am a recent graduate, I do have some valuable experience that will enable me to be an excellent addition to your design team. I recently graduated with a Strata one in graphic design, and the course includes product design modules. Moreover, I have competed in several design competitions and won a gold medal in a product design competition in Thailand last year, in which I designed a self- heating mug. Details of this prize and other prizes that I have won are included in the enclosed curriculum vitae. I am looking forward to a positive reply from you. Thank you for your kind consideration and time. Yours sincerely,
Almira Aulia
