Power And Distribution

Question 1

What 3 items do you need to generate power?

Answer 1

Prime mover
AC gen (alternator)
switchboard

Question 2

Examples of a prime mover

Answer 2

Gas turbine
Steam turbine
Diesel engine

Question 3

What does a switchboard do?

Answer 3

Control and distribute power around the ship

Question 4

How many generators does a ship generally have?

Answer 4

4

Question 5

Name components of a Main Electrical Distribution system

Answer 5

Prime mover
Generator 
Supply breakers
Switch boards
Bus bar
Electrical Distribution Centres (EDC)
Feeder breakers 
Bus bar linking breakers interconnecting

Question 6

“As Fitted” package contains which books

Answer 6

The power book
Low power and lighting book
Portable apparatus book

Engineers fittings reference book

Question 7

Power book shows..

Answer 7

The distribution of all 450 volt services

Drawings of gens and switchboard circuit + distribution circuits

Question 8

Low power and lighting book shows ..

Answer 8

Distribution of 115 volt

Specially concerned with lighting

Question 9

Portable apparatus drawing book shows..

Answer 9

Distribution of 115/230 volt services

Specifically concerned with power supplies to 115/230 volt sockets

Question 10

Where can the books be found on ship?

Answer 10

Central place i.e main switchboard or electrical workshop

Question 11

What’s the main supply fed to an electrical distribution centre (edc)

Answer 11

450v 60Hz 3 phase

Question 12

What’s an MCCB?

Answer 12

Moulded case circuit breaker

Question 13

How many phases required for a lighting circuit?

Answer 13

1 phase

Question 14

What’s the purpose of breakers and fuses?

Answer 14

The protect the power supply

Question 15

What’s the first breaker to trip?

Answer 15

MCCB

Question 16

What’s the last breaker to trip?

Answer 16

Supply breaker

Question 17

Control of power and distribution is done from 2 positions. Name them

Answer 17

Primary control position (PCP)

Secondary control position (SCP)

Question 18

Primary control position (PCP) controls…..

Answer 18

All main breakers
All gen voltages
All gen frequencies
Anti condensation heaters in switchboard

Question 19

Secondary control position (SCP) controls…..

Answer 19

Breakers controlled by section switchboard
Voltages of gens controlled by section switchboard
Frequency of gens controlled by section switchboard
Anti condensation heaters in switchboard

Question 20

What are the 6 meters in a switchboard?

Answer 20

Voltmeter
Frequency meter
Watt meter
Ammeter
Syncroscope
Earth fault indicator

Question 21

What are the 6 indication lights on a switchboard?

Answer 21

Control available/ not available 
Gen running
Fire detected
Over temp
Breaker tripped
Earth fault

Question 22

9 steps for connecting to shore supply

Answer 22

1. Send signal to port
2. Raise permit to work
3. Rack out breakers
4. Prove box ‘dead’
5. Obtain castle key
6. Test shore supply
7. Bring on and secure cables
8. Connect cables
9. Inform dockyard

Question 23

When earthing for a shore supply where must the ship be earthed to?

Answer 23

The jetty
To the ship alongside
At 2 points not less than half the ships length apart
Gangways

Question 24

What are the 3 categories of change over switches

Answer 24

Automatic change-over switch (ACOS)
Remote operated change-over switch (ROCOS)
Hand change-over switch (HCOS)

Question 25

All equipment generating or operating at greater than ......AC OR ......DC ‘it’s been earth bonded

Answer 25

35v AC | 50v DC

Question 26

What can you use to earth bond?

Answer 26

``` Metal box Cabinet Console Cubicle Frame Starter ```

Question 27

2 types of portable electrical equipment

Answer 27

Class 1 | Class 2

Question 28

What is used to connect two busbars in the same switchboard together?

Answer 28

Busbar linking breaker

Question 29

What requirement must exist to connect two busbars together?

Answer 29

Same voltage

Question 30

How many earth cables are required when the ship is alongside a jetty on shore supply?

Answer 30

2

Question 31

What’s the purpose of a changeover switch?

Answer 31

To provide normal and alternative supply to normal equipment

Question 32

What is sent from the ship 24 hours before arriving in port?

Answer 32

A logistical signal requesting shore supply

Question 33

Name the key that makes shore supply safe while connecting to the boxes?

Answer 33

Castel key

Question 34

What would happen to a motor if the phase rotation was wrong?

Answer 34

It would go backwards

Question 35

What does SCC stand for?

Answer 35

Ships control centre

Question 36

Why are there separate 115v earth testing facilities?

Answer 36

No physical connection due to transformers

Question 37

Explain breaker discrimination

Answer 37

If there was a major fault on the ships supply system the main breaker would not trip straight away. The MCCB would be first to trip then the feeder breaker etc

Question 38

What is the reference book used for?

Answer 38

Used in conjunction with the power book and lists all fittings, the number fittings, component symbols and pattern numbers

Question 39

What’s the ratio for 440v fuse discrimination?

Answer 39

3:1

Question 40

What does MCR stand for?

Answer 40

Machine control room

Question 41

What are the breaker operating switches found on a switchboard called?

Answer 41

Discrepancy switch

Question 42

What’s the maximum current capacity for shore supply?

Answer 42

2000A

Question 43

What is used to confirm the correct phase connection with respect to shore supply

Answer 43

Phase sequence indicator