Power & Distribution

Question 1

how many diesel generators are fitted to a distribution system

Answer 1

four

Question 2

what does EDC stand for

Answer 2

Electrical distribution centre

Question 3

how many EDC’s are fitted to a distribution system

Answer 3

four

Question 4

What does MCCB stand for

Answer 4

moulded case circuit breaker

Question 5

list the 5 main breakers fitted to a distribution system

Answer 5

• supply breaker
• shore/supply breaker
• busbar linking breaker
• interconnector
• feeder breaker

Question 6

what is the power book

Answer 6

shows the distribution for all 440v services

Question 7

what is the lighting book

Answer 7

• includes low power
• shows postcode / layout for lighting circuits
• 115v/230v

Question 8

what is the reference books

Answer 8

books provide images and information covering the ships systems and equipment fitted

Question 9

what is the ratio for 440v fuses

(fuse discrimination)

Answer 9

3:1

Question 10

what is the ratio for 115v fuses

(fuse discrimination)

Answer 10

2:1

Question 11

explain breaker discrimination

Answer 11

• First breaker to trip is the MCCB
• Last breaker to trip is the supply breaker (otherwise all power will go out)
• Breaker nearest the fault is the first to trip
• Breaker furthest from the fault is the last to trip

(kettle wont trip a generator)

Question 12

what does MCR stand for

Answer 12

machinery control room

Question 13

What does PCP stand for

Answer 13

primary control position

Question 14

What does SCP stand for

Answer 14

secondary control positions

Question 15

what are the three basic items that a distribution system needs

Answer 15

prime mover
generator
switchboard

Question 16

list the meters fitted to a switchboard generator section

6 in total

Answer 16

• voltmeter
• ammeter
• kw meter
• frequency meter
• syncroscope
• earth meter

Question 17

where are breaker operating switches found and what are they called

Answer 17

• dicrepency switch
• located in pcp

Question 18

describe the connection of shore supply

Question 19

what are the rules regarding eathing the ship when connecting shore supply

Answer 19

• ship must be earthed to either the jetty or ship along side
• by at least 2 points, not less then half the ships length
• ganway needs to be earthed

Question 20

what is used to confirm correct phase rotation

Answer 20

• the phase sequence indicator (2 lamps)
• the right one should be brighter

Question 21

what would happen to a motor if phase rotation is wrong

Answer 21

motors would run backwards

Question 22

list 3 types of hand changeover switches

Answer 22

• normal/alternative
• normal/emergancy
• normal/alternative/emergancy

Question 23

list 3 kinds of changeover switches

Answer 23

• ACOS
• HCOS
• ROCOS

Question 24

what & where are the 440v earth testing facilities found

Answer 24

• earth indicator light located on the switchboard
• some also have audible alarms

Question 25

why are there seperate 115v testing facilities

Answer 25

115v is a transformed supply and the secondary winding (output side) is not physically connected to the primary wiring

Question 26

what does C&C stand for

Answer 26

control and communications (switchboard)

Question 27

define what a converted supply is

Answer 27

has its voltage and/or frequency changed from 450v, 60Hz

Question 28

what are the main voltage & frequency used in the C&C switchboard

Answer 28

* 24v DC * 115v, 400HZ

Question 29

what are the 2 catagories for batteries

Answer 29

* primary * secondary

Question 30

what are the characteristics of the 2 batteries

Answer 30

primary - dry - not rechargable, usually small secondary - wet - rechargeable, vary in sizes

Question 31

how many diesels generators are fitted to a type 23

Answer 31

four

Question 32

what is the output of the generators fitted to a type 23

Answer 32

* 600v * 61.2HZ * 62.3 phase * 63.13mw

Question 33

why do we produce the 600V for a type 23

Answer 33

440v system would not have given a large enough range of speed

Question 34

what are the 7 breakers fitted to a type 23 P&D system

Answer 34

* generator supply breaker * interconnector breaker * shore supply breaker * electric motor air circuit breaker * motor generator feeder breaker * motor generator supply breaker * 450v supply breaker

Question 35

what does the converter regulator do

Answer 35

converts and regulates the voltage at 750v DC

Question 36

what is the voltage required for the ships services and how is it produced

Answer 36

the 450v required for ships services is generated by a motor generator

Question 37

what are EDC's and many types are fitted

Answer 37

electrical distribution panels there are 3 types