revision Flashcards
what is the power book and when is it used?
it shows the distribution of all 440v services used when tracing which services are fed from which fuse panel.
what is the lighting book and when is it used?
shows the 115v / 230v and is used the same way as the power book
what is the reference book and when is it used ?
used in conjunction with the power book and lists all fittings, number fitted, component symbols and pattern numbers
explain breaker discrimination
it would be impossible for a fault on a mess deck kettle to trip a main generator .
what does MCR stand for ?
machinery control room
list the meters fitted to a switchboard generator section
voltmeter
ammeter
kw meter
frequency meter
syncroscope
earth fault indicator
where are the breaker operating switches found and what are they called ?
start / stop, selector, control and discrepancy switches located in the pcp
what are the rules regarding to earthing the ship when connecting shore supply ?
the ship must be earthier either to the jetty or to the ship alongside by at least two points no less than half the ships length apart
what is used to confirm correct phase rotation with respect to shore supply ?
the phase sequence indicator (2 lamps) the right one should be brighter
what would happen to the motor if the phase rotation is wrong ?
motors would run backwards
list 3 types of hand change over switches
normal / alternative
normal / emergency
normal / alternative /emergency
list 3 types of change over switches
hand change over switch
automatic change over switch
remote operated change over switch
what and where are the 440v earth testing facilities found ?
earth indicator light located on the switchboard, some also have audible alarms
why are there separate 115v testing facilities ?
115v is a transformed supply and the secondary winding is not physically connected to the primary winding
what does CandC stand for ?
control and communications (switchboard)
define what a converted supply is ?
a converted supply has its voltage and or frequency changed from 450v, 60Hz
what are the voltages used in the CandC switchboard ?
24 volts DC
115 volts 400 Hertz
what and where is the earth testing facilities for 24v DC ?
an earth test panel on the switchboard provides for testing the positive and negative side of the DC supply. A push button with integral lamp is fitted to the switchboard
what does RTR stand for?
rationalised transformer rectifier
what does TRU stand for ?
transformer rectifier unit
what two categories do batteries fall into?
primary and secondary
what are the characteristics of the two batteries ?
primary - dry , not rechargeable , usually small
secondary - wet , rechargeable, small to large
what is the capacity of a battery measured in ?
amp-hour (Ah)
what is the voltage of a fully charged cell ?
2.1v