Incandescence ljnken'desnsl «a×m, «×mוa«×«

Incandescent lamp [,inken'desnt lamp] nauna iiaxaniiaaiiii×

-6)-

to conven [kan'va.1]

to deliver ldi'liva]

according to Ja'ko:di5 tal

etc. = ct cetera l,et 'setara)

cornaciio

2. Read tbc words and put down tbelr Russian equivalents:

['kemikall chemical

['dJenareita] generator

lma'tiaria1 _l material

|miI‹anikal] mechanical

[9a:rnll thcm›al

[’rh0Uta] motor

3. Translate into Russtsn:

   1. convertible values, protected power source, various fuses, variable in- sistem, chemical cells

b. cells delivering elecaic power

generator converting mechanical energy

circuits utilizing common fuses

c. Primary cells deliver electric power.

Different kinds of energy can be converted into electric energy. Protection devices are utilized in any circuit.

Components of Electric Circuits

The main components of any circuit are devices that produce and

utilize electric energy. They are: 1. power sources, 2. utilizing loads,

3. connecting conductors.

The most common power sources are electric generators and primary

cells. Electric generators convert chemical energy into electric energy.

Loads include electric heaters, electric motors, incandescent lamps, etc. Motors convert electric energy into mechanical, incandescent lamps and heaters convert electric energy into light and heat. Utilizing devices or loads convert electric energy into thermal, mechanical or chemical energy.

Electric power is delivered from power sources to loads by electric wires. According to their material, wires can be aluminium, copper, steel, etc.

Besides, electric circuits use different types of switches, protection devices (relays and fuses), and meters (ammeters, voltmeters, wattme- ters, etc.).

4. Complete the sentences using the correct verient:

l . The main components of elflGtriC a) loads and wires.

circuits are b) power sources, load and wires.

2. Power sources are used a) to produce electric energy.

b) to deliver it to the loads.

3. Electric conductors are used

3. Protection devices are utilized

5. A switch is utilized

1. to connect the circuit elements.

2. to deliver electric power.

1. in some circuits.

2. in any circuit.

1. in some circuits.

2. in any circuit.

1. What are the main components of an electric cir$uit?

2. What is the function of an electric source?

3. What is the function of a load?

4. What is the function of wire conductor?

5. What other devices are utilized in a circuit?

6. Say e few words about your electrical engineering leboretory. Say whet power sources end whet loeds are utilized there. Have a talk with your groupmete ebout their types end their operation.

1. a) Cover the right column end read the English words. Trenslete them into Russian end check your trensletion.

6) Cover the left column end trenslete the Russian words beck into English.

efficiency ignorance

dependence

oTjtava, 3i|›i|›exTnBnoczs

3BBHCHMOGTh CTOHMOCTb

- 63 -

length		4Jixxa
tO t BO£9		HC £f]9H£tNMSTb BO BftNM8H£jC
to depend (on) to exceed	[ik'si:d]	38B£tCCEk /OT) npesuuiazs
exceedingly per cent		•ipesaiu•iaRuo, o•ieus npouewr

Read the words and put down their Russian equivalents:

[’stei{an]	station
l,endJi'niaJ [,endJi'niari9l	engineer engineering

^{Put down the nouns corresponding to these verbs. FoGow the model.}

Model. in act - action

to ignore - to depend - to cost -

^{Trensletc into Russian:}

e. line efficiency

to produce -

to use

to lose

power station

b. interdependent values interconnected sources

changing power efficiency

d. One can ignore these exceedingly low power losses.

One should take into consideration the interdependence ofthDsD VBlllDS.

One should not ignore the high cost of these installations.

Electric Llnes end Thelr Efllclency

Wires are used to deliver electric power and to intemonnect different components of electrical installations. Conductor used for electric

wiring are commonly produced of copper and aluminium. Aluminium is Widely used nowadays due to its low cost. Copper is also widely used in electrical engineering but its cost is much higher.

Wires connecting the components of various installations may be in- sulated. They may also be used without insulaBon. Since in short lengths of wire power loss is exceedingly low one can ignore it. In long wires (longer than 10 in), power loss cannot be ignored since it is rather high. Power loss in a line should not exceed a definite value. If this value is exceeded the line becomes inefficient.

One should know that the efficiency of a line is not constant — it may change. The value of the line efficiency depends on the load: the greater the load the lower is the line efficiency. At voltage losses of 2 to 5 per cent the efficiency of a line is 98--95 per cent. Protecting devices, fuses and relays are used to protect the circuit against overcurrents and short-circuits.

19. Complete the sentences using the correct variant:

    1. Aluminium is used due to its a) high cost.

b) low cost and high efficiency.

2. Cross-section of different conductor

3. Power loss can be ignored

4. A definite value of loss

5. Electric lines nowadays are

6. Installations are protected

1. in shon wires.

2. in long wires.

1. can be exceeded.

2. should not be exceeded.

1. efficient.

2. inefficient.

1. by switches.

2. by fuses.

6. Complete these sentences using wfitfe. Follow the model on page 13:

19. The cost of aluminium is comp8ratively low while

2. In a short length of wire power loss is extremely low while ..

3. The greater the load the lower is the efficiency of tb.e line

6. Answer these questions:

1. Why is aluminium widely used nowadays?

2. Is its cost very low or comparatively low?

- 65 -

3. What is the cross-section of copper conductors?

4. May one ignore power loss in short wire? Why?

S. What docs the efficiency of a line depend on2

6. What are fuses used for?

7. When does a line become inefficient?

^{Think of three questions about thls extract end put them to your} groupinate.

When elecaic energy is produced at the power station, it is to be trans- mitted over elecaic wires to the consumer. Wire conductor offer resis- tance to the current flow; the longer the wire, the greater is in resistance to the current flow. Accordingly, the higher the offered resistance, the greater are the heating losses in the wire.

^{a) Cover the right column end reed the English words. Translate} them into Russian end check your translation.

b) Cover the left column and trenslete the Russian words beck into English.

area distance network support cord

bus c‹tterprisc to terzn

to divide

to support to distribute accordingly as to

long distance

length of transmission lines power consumption distribution centre

citv area

['caria]

['entapraiz] [di'vaid]

- 66 -

fUtOLL@Ab, Jt8CTb

paccroanue

CeTb 3J7CET(3DJTHHH

onopa, uavze nposon

npeztnpit»zne

HB3b£B8Tb, NM HOB8Tb

/tenrrrs, pa3/tenxzs TtOA,B.C[3JCttB6Tb [3SCTT[3 /tCJfRTb COOTBCTCTBCNHO

³tTo xacsercx; . . . ³fTO /to

6onkuJoc pacczoxnne AJinna JTFfHN9 ncpeztavn nozpe6ncnne 3neprxn

pacnpejtcnnzensxu9 ucinp

pa9o roponcKo9 3ampo9xn

Put down the Russian for: interdependent city’ areas		_
interacting underground lincs	_			_
interconnected overhead lines							“
transmission and distribution lines overhead lines step-down transformer indoor lines			_		_	_
underground lines

Transmission Lines

A power system is an interconnection of electric power stations by high voltage power transmission lines. Nowadays the electricity is trans- mitted over long distances and the length of transmitting power lincs varies from area to area.

A wire system is termed a power line in case it has no parallel

benches and a power network in case it has. parallel branches.

According to their fiinctions, power lines and networks are subdivided into transmission and distribution lines.

Transmission lincs serve to deliver power from a station to distribu- tion centres. Distribution lines deliver power from distribution centres to the loads.

Lines are also classed into: I) overhead; 2) indoor; 3) cable (under-

ground).

Overhead lines include line conductor, insulator, and supports. The conductor are connected to the insulator, and these are connected to the supports. The greater the resistance, the higher are the heating losses in the conducting wires. In order to reduce the losses, a step-down trans- former can be used.

Indoor lines include conductor, cords, and buses. The conductor may

include one wire or a combination of wires not insulated from one an-

other. They deliver electric current to the consumer.

As to underground lincs, they are used in city areas. Accordingly, they am used in cities and towns, and in the areas of industrial enterprises.

3. Complete tbesc sentences using tbe correct variant.

1. Electric power is transmitted a) by electric lines.

b) by power networks.

-6J-

2. Lines are divided into

3. An overhead line includes

4. The insulators are connected

5. Conductors consist of

1. overhead and underground.

2. overhead, indoor and underground.

1. conductors and supports.

2. conductors, insulators and supports.

a) bare wire.

6) insulated wire.

5. Underground lines are used a) in cities.

6) in areas of enterprises.

c) in agricultural areas.

4. Complete tbc sentences using sitIe or as to. Follow tbe roodcl on page

2. Trenimission flues deliver power from a station to distribution ccn-

2. Low current results in decreased heating losses ..

3. Overhead lincs arc used in open areas ..

Answer these questions:

1. By whBt means is electric power system transmitted?

2. Which system has no parallel branches?

3. into what groups arc all the tmnsmitting lines classed?

4. wrist components does an overhead line have?

s. What elements do conductors consist of7

6. In wha areas arc overhead (underground) lines used?

a) Cover the rlght column end reed the English words. Tmnslnte

them Into Russlen end check your tmnsletlon.

6) Cover the left column and trsnslete the Russlen words beck trite

6c3on8cxocrs; ripcnoxpanxrcnsiruR

danger |'de‹nd$a]

strength [streg6]

earth la:8l

ground

dead [ded] dangerous |'deind$ras] strong

[law]

^dr›

wet

O£l6CHOCTb

ciuia

3aseuneiiue, 3eues seuns, no•iaa asixiiio•ieiiiisilt

on6CHbt9

cxxansiR, 9[3KHit (o cee»te)

Cri8c81b

HC³£C36Tb

£lO9BJT9TbC9

£IO,0 HETI]398C HHC54

cyxoR

csipoR, uoxpsiR

Reed the words and put down tbeir Russian equivalents. Tbcn trans-

late them back into Englisb (orslly).

['&tmasfia] [,pasa'nel]	atmosphere personnel
['kantakt] ['regjula]	contact regular
[kan'troul]	control
[di1ekt!	detect

PufdownfNecorrwpondin¶zouns.Formnounsfrom(Nesemdjacti**s

end translate them into Russian.

Model. wide -width

broad —

high —

Put down the Russian for:

under voltage under 20 V over 30 V the power is on the power is off great sscngth dry air dead conductor live conductors

- 69 -

5. Choose the suitable words and translste the sentences:

I . The danger of electric shocl: (appears, disappears) when the conductor

becomes (live, deadj.

^2. Cu^ur^rr^renⁿt passes through faulty (e‹irf/icd, unearthedj part of installations when the pow'er is on.

Low accuracy of measurement is (‹zii advantage, a disadvantage) of the measuring device.

^4. The danger of electric shock (iiicreores, decreores) in the wet 8nd hot atmosphere.

5. NO current flows through a (de‹id, live) conductor.

5. Fill in using the verbs to detect, to eppenr, ip dfsnppenr, fp dccrresc:

I . When resistance increases, the ^risk of electric shock

3. Electric power . . only on live conductors with power on.

4. When the device is switched off electric power ..

Safety Earthing System. Electric Shock

The strength of current depends on both the voltage and the tests- tance in a circuit. A current of 30 mA is dangerous for a man and a cur- rent of 100 mA and higher is lethal.

1. Contact with an ungrounded 6) Contact with a grounded motor motor frame frame

Fig. 19

Earthing system serves to protect amending personnel from electric shocks when voltage appears on parts that are normally dead. The risk of an electric shock decreases with decreasing voltage. In wet and hot atmosphere the risk of electric shock increases. Safe voltage for circuits used in dry atmosphere is under 36 V. When the power is on, contac:s with live conductors are dangerous for life. Thus, measures are taken to

protect attending personnel from contacts with live parts of installations under voltage.

^{The danger} of an elecnic shock disappears provided the metal parts

URdGf VOltage are connected with ground by means of

safety earthing.

Connecting to ground is made by means of earthing electrodes

which are connected directly with ground.

The insulation resistance of any installation should be regularly controlled by means of measuring devices. The faulty parts should be detected, eliminated, and replaced by new ones.

7. Complete the scatcaccs usiag the correct variant:

1. Earthing system serves a) as protection born an electric shock.

b) as connection with ground.

2. Voltage appears on

1. dead parts.

2. live parts.

3. Contact with live conductor is a) dangerous.

4. Connection to ground is made a) by means of wire conductors.

b) by means of earthing clccoodcs.

5. Danger of an electric shock a) is earthed.

disappears if the 6ame 6) is unearthed.

8. Complete the sentences using wfiJfe. Follow the model on page 13.

1. The insulation resistance of a faulty unearthed frame is extremely low

2. Danger of an electric shock disappears when the faulty parts are

3. One should work on the circuit when the power is off. One should not work on the circuit when the power is ..

4. Contact with dead conductor is safe ...

5. In dry air the risk of an electric shock decreases ..

1. What does an earthing system serve for?

2. What parts arc termed dead (live)7

3. In what air dons the risk of an electric shock decrease?

4. By what means is connection to ground made?

5. What dons an electric shock result born?

6. Is a current of 50 mA dangerous for a man?

7. Is wet and hot atmosphere dangerous for the amending personnel2

8. Docs tbc risk ofBn clccoic shock decrease with increasing currcnt7

10.Rcxd the text and write four questions about Ie Ask your groupraatcs

A man can get an electric shock when he comes into contact with the electric fish. One of this kind is found in the tropical watem of South America: it is the electric eel. Small electric eels, one inch long, give a small shock. When the fish is 6 inches long its internal battery gives as much as 200 volts. A very big fish can generate 600 volts! When it is short- circuitcd, a current of one ampere can be obtained. A two-meter long eel can light a’dozen 50 watt lamps. The eel’s head is positively charged and the opposite end is negatively charged.

1. n) Cover the rlght column end mad the English words. Tmnslate them Into Russian rind check your tmnslntion.

b) Cover tbc left column and translate the Russtao words back iato Eogllsb.

torque	[to:k]	spautcuxc, uoucur apautcnxe
poor nameplate	|pua] ['neimpleit]	0cx›zuA, iuioxoA (zaeoncxee) za0xrr•ixa

2. Rcxd the words aad put dowo their Russian equivalents. Thca trans-

late tticra back Into English.

['indastri]	industry
[1rnnspa:I] l'nioutuJ	aaiisport winter

['prnktikal]	practical
[pou1en(al]	potential

3. Give the Russian for:

magnet pole different conduit machine ratings rated torque service life poor operation

3. E’orra adjectives aad adverbs. Translate thcra tato Russias.

1. cerc — careful

c. normal — normally

l. What types of magnets are used in heavy industry?

2. How long is motom’ service life under normal conditions?

3. Are motom used in every branch of industry?

4. What are the main types of motors in use nowadays?

Electric Motors

Motors are used for converting different forms of energy into me- chanical energy.

The main part of a motor is a coil or armature. The armature is

placed between the poles of a powerful magnet. When a motor is put

into operation current starts flowing through the coil (armaturc) and the armature starts rotating.

Electric motors are used practically in every branch of industry,

transport, and agriculture. Naturally, they are pr ferent designs. They are used in industrial plants, ferent conditions.

ced many dif- under dif-

Each motor is supplied with a nameplate which bears machine ratings: output power, voltage, the rated current, the starting current, the power factor, the efficiency, and the rated torque.

These motor ratings should be taken into consideration since they are necessary for the users. On them depends the length of motom’ service life, which is normally equal to about 10 years, provided that the operating conditions are normal. Naturally, under abnormal condi- tions the service life becomes much shorter: motors opemte poorly and may have different faults.

1. Motors are used a) for transmitting energy.

6) for converting energy.

2. Motor’s main part is

3. The armature is placed

6) the armature.

c) the stator.

1. between the poles of the magnet.

6) about the poles of the magnet.

4. Motom’ service life becomes a) under normal conditions. shorter 6) under abnormal conditions.

5. Faulty motors operate a) normally.

6) poorly.

7. Aaswcr these questions. Use thcra io a talk with your groupmatc:

l. Wh8t are motors used for?

2. What is the motor’s main part?

3. Where is the armature placed?

4. What ratings does the nameplate of a motor bear7

5. Under what conditions does a motor operate normally (poorly)?

Energy Resources of Today

People are energy-rich today. Solar energy is considered to be a poten- tially limitless source of clean energy. The waters of the world contain pp- tential fuel — in the form of a special isotope of hydrogen — deuterium. It is sufficient to power fusion reactors for thousands of years.

1. a) Cover the right column and read the English words. Tmnslatc them Into Russian and check your imnslation.

2. Cover the left column and translate the Russian words back into English.

to repair

brush

spark speed noise

[ri’pca]

[brx[]

383D]9, JOO T

excessive [Ik'seslv]

check

to adjust

riposepxa

peryniipoaais, noarousrs

2. Read the words aad put dowa their Russias equivalent:

['komju:teita] convnutator [’ste‹ta] stator ['routa] rotor ['kontekt] contact [kan1xkt] to contact ['prouses] process

check	to check
sperk brush

rcp8ir

slow (od¿)

4. Put down the Russian equivalents of these word combinations. Trans- late them back into English (orally).

brush sparks slow speed excessive speed safety devices

1. What do motors’ faults result from?

2. Are there any faults th8t can be ignored?

3. What makes motors’ service life shorter?

4. What does voltage supply stop result in?

5. What processes show the (dis)advantages of devices?

I . New motors are given a no-load and under a load tests.

2. When the motor is tested it should produce no abnormal noise.

3. In case this noise appears the motor must be disconnected.

4. This generator must be checked; one should give it a test.

5. The motor’s brushes seem to be sparking. Can you see the sparks?

6. The windings of the coil are shorted. I h8ve detected 8 short in the

windings.

2. The armature rotates slowly; let’s check it up!

3. The speed of rotation is too excessive; it must be slowed down.

4. In case the rotor brushes against the stator, the motor operates slowly.

The faulty brushes should be replaced.

Faults of Motors end Ways of Their Repair

Motors may have different faults. A faulty motor does not start, or,

when it is started, it operates at an excessive speed.

Its brushes may spark and its windings and the commutator m8y be overheated and burnt. Besides, a motor may produce an abnormal noise, etc. All these and other f8ults should be detected and repaired.

In case the motor does not stan it may have different faults (see the ta- ble):

-J6-

Possible causes offaults Ways ofre_Rair

1. Fuses are faulty. 1. Replace the fuses.

2. Motor is overlo8ded. 2. Reduce motor load.

3. Circuit in armature winding has an 3. Repair the arm8ture open. winding.