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
what is the voltage of a discharged cell ?
1.75v
what is the output of the generators fitted to a type 23?
600v, 61.2Hz, 3 phase
what does the converter regulator do ?
converts and regulates the voltage at 750v DC
what are EDPs and how many are fitted?
three types of electrical distribution panels are fitted to type 23s
what are shedable services and why do we have them?
shedable EDPs provide power supplies to non-essential equipment
what would happen if we were to lose both motor generators and how is this achieved ?
the 600v generator can be re configured to supply 450v to the 450v system via a 4 position switch at the rear of the switchboard
when are the navigation lights tested and by who ?
lights are to be tested daily one hour before sunset, normally by the duty ETME
whose permission must be gained first before testing navigation lights ?
permission must be gained by the
OOW/ OOD
where are navigation lights controlled from and switched on and off ?
the navigation lights control panel, located on the bridge
list all statutory nav lights and their colours and location
side lights- port (red) starboard (green)
the mast head steaming light- forward and aft (white) and stern light (white)
where are special operation light switched on from ?
these are operated by the VCS 428 unit
list all miscellaneous lights, their colours and location
anchor lights- on top of the fwd and aft jackstaffs and white i colour
masthead obstruction lights- red in colour and mounted port and starboard at the top of the mainmast
how are the emergency navigation lights fed ?
they are fixed in position adjacent to their normal counter parts and are supplied via fixed wiring by two series-connected 12 volt batteries
why is it important to switch on the emergency NUC/RAS lights before being hoisted ?
if they are hoisted then plugged in and induced current may be present due to radar and radio aerial interference
list the four main components of a fluorescent light fitting
starter
tube
choke coil
switched supply
