Английский язык для моряков / Англ Труханова

UNIT 7.

SHIP'S POWER PIANТS AND NEТWORКS

1. SHIP'S POWER PLANTS

Ship's power plant is а complex of primary mechanical motors, electric generators and distribution gears with control and protection de­ vices.

Ship's power plants are classified according to their function, kind of current, type of primary motor, voltage and mode of control.

According to their function, power plants can Ье subdivided into:

а) lighting pqwer stations, having а power up to 100 kW; Ь) com­ bined power stations (for power and light consumers supply)- 6000 kW and more; с) emergency power stationsup to 500 kW; d) power stations for electric propulsion - up to 140.000 kW; е) auxiliary power stations for electric propulsionup to 15.000 kW.

According to the kind of current, they are classed as power stations of direct or alternating current.

According to the type of primary motor, there distinguished: а) diesel generators, Ь) steam generators; с) turblne generators; d) shaft generators.

According to the voltage: the rated voltage on the electric power supply terminals should not exceed: а) at а direct current230 V; Ь) at а one-phase altemating cuпent - 270V; с) at а three-phase altemating cuпent460 V.

According to the mode of control, there recognized: а) non-au­ tomated, Ь) partially automated; с) automated power stations.

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DISTRIBUТION (SWITCH-) GEARS

Distribution gears are such constructions which serve to ac­ commodate commutating, protective, regulating, signalling apparatuses and electric measuring devices. Thus, they ensure control, protection and regulation of electric installations and power plants operation as well as measuring of electric power supply sources parametres.

Distribution gears are·classified according to their function; kind of current, design, mode of installation and fastening.

According to the function, ihere distinguished: а) main distribu­ tion boards (switchboards), intended for control, protection and regu­ lation of basic generator units parametres as well as for electric power distribution over its consumers; Ь) emergency distribution boards, per­ forming the same function as the main ones but for emergency generat­ ing units and their consumers; с) control panels (consoles), exerting remote control and control over the generating units and essential pow­ er consumers operation; d) coastal power supply boards, intended for energy delivery from the coast or from other ships; е) switchboards, which serve to ensure power supply in а certain part of а ship. They are supplied from main or emergency distribution boards; t) separate con­ sumers boards, exerting control over operation of essential consum­ ers, having а complicated mode of operation; g) electric power con­ verters boards are similar to main distribution boards but designed for electric power converters and their consumers.

According to the kind of current, there recognised switchgears of а) direct current, Ь) altemating one-phase and three-pbase cur­ rent.

According totheir design, switchgears can Ье: proof, drop-proof, splash-proof, water-proof and watertight, explosion-proof, hermetic.

According to the mode of installation and fastening, there can Ье а) suspended switchgears of а leaning type, which are installed on а

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VOCABULARY

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1О. What is the difference between emergency distribution boards and main ones?

11.What are the functions of:

•control panels?

•coastal power supply boards?

•switchboards?

•separate consumers boards?

•electric power converters boards?

12.What currents can switchgears run on?

13.What peculiarities of switchgears' design do you know?

14.How can switchgears Ье installed on board ships?

2. POWER PLANT SWITCHGEAR EQUIPMENT

According to the function, switchgear equipment is subdivided into switching, protective, switching-protective, measuring, control and sig­ naling equipment.

Switching equipment serves for electric circuits switching-in, switching-off and switching-over. Among switching equipment are: knife switches, knife-Ыade-type switches, packet switches and universal switches

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Protective equipment is intended for protection of electric ener­ gy sources, circuits and consumers against overloads, short-circuits, volt­ age drop, inverse current and inverse power. Among protective equip­ ment are fuses and relays.

Switching-p1·otective equipment is applied for electrical instal­ lation switching-in, switching-offand protection. Automatic switches of different types refer to this kind of equipment.

Measuring equipment (ammeters, voltmeters, wattmeters, pha­ someters, megohmmeters and synchronoscopes) is destined for the con­ trol over the electrical insta\lation normal operation.

Control equipment is intended for stabilization and control of the electric circuits preset parameters. lt сап Ье manu<1I or automatic. Among manual control equipment are rheostats of different types and

excitation controllers.

Signaling equipment is designed for signaling about the electric circuits state and the position of the switching equipment. It includes light and audiЫe signaling devices.

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QUESTIONS

l. How is switchgear equipment subdivided according to its function?

2.What does switching equipment serve for?

3.What is protective equipment intended for?

4.What is switching-protective equipment applied for?

5.What is measuring equipment destined for?

6.What is control equipment intended for?

7.What is signal equipment designed for?

3. SHIP'S POWER NEТWORK

Ship's power network is а complex of electric саЫеs, wires, switchgears and accessories, which serve for electric power delivery to the consumers.

According to their function, networks are divided into:

•Power mains, intended for power consumers' supply, i.e. differ­ ent electric drives and poweiful electric heating devices.

•General lighting network, which, in its tum, is subdivided into:

а) ship's accommodations lighting network; Ь) engine room and boiler room lighting network; с) outside lighting network; d) hold lighting net­ work.

•Emergency lighting network, which is supplied from the main distribution board through the emergency distribution board and usually has no switches.

•Battery-powered emergency lighting network, which is switched on automatically, when the voltage on the main or emergency distribution board vanishes.

•PortaЫe low-voltage lighting network, which is used while ex­ amining and repairing the equipment. lt is supplied through bucking transforrners or, if electric power distribution is perforrned on norrnal voltage, through plug-transforrners.

•Light-current installations network includes engine and rud-

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der telegraphs networks, tachometers, salinometers, pyrometers, resis­ tance thermometers networks as well as networks oftelephone commu­

nication and alarm ( fire, emergency, watch, etc.)

• Electric radio navigation equipment network comprises gy­ rocompass, echo sounder, log, radio pelorus etc. networks.

Electric networks are made of ship's саЫеs and wires. The ship's саЫе is one or several isolated electric conductors, having one or sev­ eral mutual protective shells, which guard isolation and current-carry­ ing conductors against mechanical and chemical effects. Marine power саЫеs isolation is mostly rated for 700 V ofdirect current and 1000 V

ofalternating current. In accordance with the type ofprotection the са­ Ыеs are divided into: non-hermetic (which are not protected against moisture), hermetic (protected against moisture in both radial and lon­

gitudinal directions), iron-clad (protected against mechanical damage) and shielded (protected against interference during radio reception and

against mechanical damage).

VOCABULARY

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QUESTIONS

1.What is the aim of the ship's power network?

2.What is the power mains intended for?

3.What is the general lighting network subdivided into?

4.How is the emergency lighting network supplied?

5.Under what condition is the battery-powered emergency lighting network switched on?

6.What is the purpose of the portaЫe low-voltage lighting network?

7.What does the light-current installations network include?

8.What does the electric radio navigation equipment network com­ prise?

9.What is the ship's саЫе?

10.What are the саЫеs divided into according to the type of protection?

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EXERCISES

L Checkyourselfin your vocabulary.

What do уои са/1:

1.а complex of primary mechanical motors, electric generators and distribution gears?

2.а construction which serves to accommodate commutating, protec­ tive, regulating and signalling apparatuses?

3.а distribution gear which serves for control, protection and regula­ tion of basic generator units parametres?

4.а distribution gear which exerts remote control and control over the generating units?

5.а distribution gear which is intended for energy delivery from the coast?

6.а distribution gear which is designed for control, protection and reg­ ulation of electric power converters and their consumers?

7.equipment which serves for e\ectric circuits switching-in, switch­ ing-off and switching over?

8.equipment which is applied for electrical instal\ations switching­ in, switching-off and protection?

9.equipment which is destined for the control over the electrical in­ stallations normal operation?

1О. equipment which is intended for staЬilization and control of the electric circuits set parametres?

11.а network which is intended for power consumers supply?

12.а network which is switched on automatically, when the voltage on the main or emergency distribution board vanishes?

13.а network which includes tachometers, salinometers, pyrometers networks, etc.?

14.а network which includes echo sounder, log, radio pelorus networks?

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II. Make sure уои have properly understood the texts given above:

1.Lighting power stations have а power: а) up to 270 kW;

Ь) over 270 kW; с) up to 100 kW.

2.Comblned power stations are intended:

а) for power and light consumers supply; Ь) for electric propulsion;

с) for emergency power supply.

3.Separate consumers boards are intended а) for control over the generating units;

Ь) for control over operation of essential consumers with а complicated mode of operation;

с) for control, protection and operation of emergency generating

units.

4.Suspended switchgears of leaning type are installed: а) vertically on deck;

Ь) on а vertical bulkhead; с) on а horizonta\ bulkhead.

5.Protective equipment comprises: а) fuses and relays;

Ь) rheostats and excitation controllers; с) automatic switches of different type.

6.Electrical instal\ations switching and protection is conducted Ьу: а) switching equipment;

Ь) protective equipment;

с) switching-protective equipment.

7.Synchronoscopes refer to:

а) switching equipment; Ь) measuring equipment; с) control equipment.

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