Technical

Question 1

Describe the airflow through a gas turbine

Answer 1

3 stage filter - treacherous paths with knit mesh filter
water trap
plenum chamber
splitter/silencer
stone guard 1x1 inch
transition duct
cascade bend
nose cone
intake flare
LP comp (5)
VIGV variable inlet guide vains
HP comp (11)
combustion cans
locating pin atomiser
igniter 4 and 8
HP turbine (2)
LP turbine (2)
power turbine (2)

Question 2

Describe gearbox

Answer 2

High speed shaft
Meta stream coupling
primary pinion to primary wheel double helical
turning gear
intermediate shaft off the primary wheel
secondary pinion to main wheel
transient break
main wheel to input SSS clutch
output to SSS clutch
internal to output goes to thrust block and PM.

Question 3

Describe shaft line basic

Answer 3

Power turbine
meta stream
gearbox
thrust block
earth strap
prop motor
earth strap
plummer block
shaft break
torsion meter
bulkhead glands
flange coupling
earth strap
plummer block
stern seal and emergency seal
SKF coupling
intermediate A
main A bracket
propellor
pilgrim nut

Question 4

How does power and distribution work

Answer 4

Diesel
generator
600v SB
MG set
440v FB
EDC
440v fuse panel
transformer
115v fuse panel
bunklight

Question 5

Components of a starter

Answer 5

3 phases IN
contactor
transformer
relay
MTPU
starter switch
lamp

Question 6

How does a solonoid valve work

Answer 6

power is sent to a copper coil that energises, this energy from the conductor repels itself away from the opposite metal, forcing the copper coil down in a mechanical motion, this mechanical movement is used to control a valve opening and closing, when the signal is applied the valve can be opened, when signal is removed the coil loses energy and closes.

Question 7

Describe the 4 stroke cycle

Answer 7

The 4 stroke cycle is the function of a diesel engine. The 4 strokes are induction, compression, power and exhaust. In induction the inlet valve is open and air is drawn into the cylinder as the piston moves from TDC to BDC. Compression is where both valves are closed and the piston moves from BDC towards TDC compressing the new air in the cylinder, as the air is compressed towards the end of the stoke it gets hot, measured atomised fuel is injected via the injector. Power happens after ignition delay, the atomised fuel ignited with the hot compressed air creating combustion, this forces the pistol from BDC to TDC. Exhaust is where the pistol returns back to TDC with the exhaust valve open, purging all the remaining exhaust gases out,

Question 8

How does a brushless generator work?

Answer 8

Rotation motion from the diesel is directed to a permanent magnet in the generator, this magnet rotates creating an EMF, two pilot excitors are fitted either side with copper windings to take the magnetic force producing 77v AC, this gets sent to the AVR where it changes the voltage to 49.5V DC where it enters the main excitor where it connects to the main rotor via EMF. The copper coils on the rotor change the current to AC which gets sent to the rectifier assembly where the current changes to DC. The DC current gets sent to the generator rotor creating an EMF to energise the copper coils on the generator stators, this creates the 600v output of the generator