Day 1 Stuff Flashcards
To learn power and distribution
How many diesel generators are fitted on a normal RN ship?
4
What does EDC stand for?
Electrical distribution centre
How many EDCs are connected to a normal distribution system?
2
What does MCCB stand for?
Molded Case Circuit Breaker
List 5 main breakers and their uses in a generic distribution system?
Supply breaker - allows to isolate the supply in case of an earth
Interconnecting breaker - allows to isolate 2 switchboards from each other
Busbar linking breakers - allows to isolate bus bars from each other
Feeder breakers - allows to isolate the drain from the switchboards
Shore/ship supply breakers - allows to isolate the ship from another ship or from the shore supply
What is the power book?
The power book contains all the 440V supply diagrams to use when circuit tracing to diagnose a problem in the 440V system
What is the low power and lighting book?
The low power and lighting book is used for all 115V systems which contains the lighting system, this is so that you can see where a problem might be
What is the discrimination ratio for 440V?
3:1
What is the discrimination ratio for 115V?
2:1
Explain breaker discrimination?
Breaker discrimination is where the breakers increase in size as you get closer to the supply to accommodate earth faults
What does MCR stand for?
Machinery control room
What does PCP stand for?
Primary control position
What does SCP stand for?
Secondary control position
List the meters fitted to a switchboard generator section
Voltages
Frequency
What meters are on the switchboard?
Voltmeter Frequency meter Power meter Synchroscope Earthfault indicator Ammeter
Where are the breaker switches found and what are they called?
Primary control position
Supply breakers
Alternative supply breakers
How would you connect to a shore supply?
Send a signal to port 24h in advance Raise a permit to work Rack out breakers Prove supply box is dead Get the castel key Test the shore side cables Bring on the cables and secure them Connect the cables Inform the dockyard
What rules are in place when earthing a ship to the shore?
2 earthing lines no less than half the ships length apart
Must be earthed to the jetty or to the ship alongside
Gangways must be earthed
What is used to ensure correct phase rotation with the shore?
Shore supply phase connection lights
What would happen to a motor if the phase rotation is wrong?
Either the motor won’t start or it will start in reverse
List 3 types of hand change over switch
Normal alternative
Normal emergency
Normal alternative emergency
List 3 kinds of change over switch
Hand change over switch
Automated change over switch
Remotely operated change over switch
Where are the 440V earth testing facilities found?
They are found in the switchboard.
It tests between live and earth and if it reads 0V then there is an earth fault
Why are there separate 115V earth testing facilities to the 440V?
Because there is no physical connection in the transformer so there can be no continuity between the 440V and 115V lines
