Control & Communications Flashcards
What does the switchboard control?
Main converted supplies.
What is a converted supply?
A supply that has had its voltage and/or frequency changed before distribution around the ship.
Name the two converted supplies on board.
24 v DC
115 V, 400 Hz, single phase
What do main low power batteries supply?
W.E equipment
Diesel engine starting
RICE ( Rationalised internal communications equipment)
How is AC converted to DC?
By transformer rectifier unit (TRU) or rationalised transformer rectifier (RTR)
What is a battery?
A number of cells connected in series
What are the two categories of batteries?
Primary
Secondary
What are the 4 characteristics of primary batteries?
Not rechargeable
Known as ‘dry cells’
Thrown away once discharged
Normally small
What are the 4 characteristics of secondary batteries?
Rechargeable
Known as ‘wet cells’
Require specialised recharging equipment
Variety of sizes
How is battery capacity measured?
Amp-hours
What is amp-hours?
The maximum amperage that can be drawn continuously until the battery is completely discharged.
How do we measure the state of charge?
Measure the terminal voltage of each cell in the battery.
What voltage is a fully charged cell?
2.1 V
What voltage is a discharged cell?
1.75 V
What is the voltage difference between a charged and discharged cell?
0.35 V
