Preview Gas Turbine Plant Questions - SeaSources
D
While standing
watch underway on a ship with the gas turbine shown in the illustration,
a fire emergency stop is initiated when which of the following occurs? Illustration
GT-
Either the primary
or reserve gas turbine module CO2 system activates.
The fire emergency
shutdown switch located on the gas turbine module is activated.
One of the UV
flame detectors is activated.
All of the above.
B
Most GTE fuel
nozzles have passages for all of the following EXCEPT __________.
Compressed air.
Cooling water.
Secondary fuel
flow.
Primary fuel flow.
D
For shipboard
main propulsion application, how does an intercooled-recuperated (ICR) cycle
gas turbine configuration compare to a combined cycle gas turbine configuration?
The combined cycle
configuration is lower in efficiency, lighter, and takes up less space.
The ICR cycle
configuration is more efficient, lighter, and takes up less space than a
combined cycle configuration.
The combined cycle
configuration is more efficient and takes up less space than an ICR cycle
configuration.
Although the ICR
cycle configuration is lower in efficiency, it is lighter and takes up less
space than a combined cycle configuration.
C
To ensure minimum
clearance between rotor blade tips and the casing of an axial compressor,
manufacturers use which of the following techniques?
Loosely mounted
rotors that expand during use.
Abrasive coatings
in the casing and hardened tips on the blades.
Metal-sprayed
coating of the casing and squealer tips on the blades.
Closely machined
tip to casing clearances.
A
Which of the following
terms refers to axial compressor stator blades?
Vanes.
Roots.
Shrouds.
Nozzles.
B
The turbine nozzles
function to direct the gases in what direction?
In the direction
opposite of turbine rotation
In the direction
of turbine rotation
Parallel to the
turbine axis
Radial to the
turbine axis
D
What is the purpose
of the Controllable-Pitch Propeller (CPP) hydraulic oil power system?
Supplies low-pressure
oil for both pitch control and stern tube sealing.
Supplies high-pressure
oil for both propeller blade actuation and stern tube sealing.
Supplies low-pressure
oil for propeller blade actuation and control oil for propeller pitch control.
Supplies high-pressure
oil for blade actuation and control oil for propeller pitch control.
C
A body that has
energy due to its motion is said to have which of the following?
Potential energy
Static energy
Kinetic energy
Dynamic energy
D
Which of the following
terms refers to axial compressor stator blades?
Nozzles.
Roots.
Shrouds.
Vanes.
B
You are on watch
on a gas turbine propelled vessel as shown in the illustration. After reducing
power in response to a high lube oil supply temperature alarm, the temperature
continues to increase. Your next step should be which of the following?
Illustration GT-
Continue to reduce
power.
Shutdown the engine.
Water wash the
engine.
Check oil consumption.
A
How are the individual
burners in a Can-type combustor arranged?
Joined by crossover
tubes.
Joined by an outer
combustion chamber.
Separate from
the air inlet to the exhaust.
Joined at the
igniter mounts.
B
Which of the following
conditions permits a gas turbine to produce 100% power?
Maximum fuel flow.
Minimum air inlet
temperature.
Maximum combustion
temperature.
Minimum air mass/weight
flow.
C
Borescope inspection
of the combustor section requires which type of light source?
150 watt
500 watt
watt
All of the above.
D
Why are the high-pressure
turbine blades generally of the impulse/reaction type?
To evenly distribute
the stress over the entire blade.
To keep the tip
pressure higher than the root pressure thereby preventing air flow over
the tip.
To keep the tip
pressure lower than the root pressure thereby preventing air flow over the
tip.
Both A and B.
D
Assuming at least
a 500 rpm for the input shaft speed from the power turbine, as shown in
the illustration, the synchronous self-shifting (SSS) clutch used on marine
gas turbine main propulsion gears, requires which of the following inputs
or conditions to make engagement possible? Illustration GT-
Availability of
low-pressure air to provide control air pressure for engagement.
Availability of
high-pressure air to provide clutch air inflation pressure.
When the input
shaft speed from the power turbine falls below the output shaft speed.
When the input
shaft speed from the power turbine rises to the output shaft speed.
C
A compressor is
operating at an inlet pressure of 14.7 (atmospheric pressure at the time
of measurement) and a compressor discharge pressure of 123 psig. Calculate
the absolute pressure ratio across the compressor __________.
8.2:1
8.4:1
9.4:1
10.5:1
B
A centrifugal
flow gas turbine uses what type of combustion chamber?
double-annular
can
can-annular
annular
B
The turbine nozzles
function to direct the gases in what direction?
In the direction
opposite of turbine rotation
In the direction
of turbine rotation
Parallel to the
turbine axis
Radial to the
turbine axis
A
Which of the following
drawbacks of a gas turbine engine provides the greatest potential for injury
to personnel?
High pitched noise.
Mechanical stresses
the engine is subject to.
High temperature
of the exhaust gases.
Susceptibility
to foreign object damage.
B
Air used to cool
the combustion liners and turbine components is referred to as which of
the following?
Primary air.
Secondary air.
Control air.
None of the above.
A
The lubrication
principal utilized by the Kingsbury thrust bearing is which of the following?
Wedge-shaped oil
film.
Square-shaped
oil film.
Cylinder-shaped
oil film.
Free-sliding oil
film.
C
Which of the following
are the principle factors that affect the performance of a gas turbine compressor?
Bleed pressure,
fuel pressure, exhaust temperature.
Fuel flow, air
flow, exhaust temperature.
Pressure ratio,
air flow, rotational speed.
None of the above.
C
Which of the following
statements is true concerning axial compressor disk-type rotors?
Rotor is only
suitable for low-speed compressors.
Rotor discs are
held together by through bolts.
Rotor discs are
shrunk fit onto a steel shaft.
Rotor consists
of rings that are flanged to fit one against the other.
A
Which of the following
is the principle that a magnetic speed sensor/pickup operates on?
Voltage is produced
when a ferrous material moves through a magnetic field.
Vibration caused
by shaft rotation can determine the speed of rotation.
Force is the product
of mass and acceleration.
Variations in
the earth’s magnetic field are caused by ferrous materials.
A
Marine GTE fuel
oil systems, as shown in the illustration, require fuel oil shutdown valves
to be __________. Illustration GT-
piped in series
piped in parallel
piped in series-parallel
manually operated
from MPCMS
C
If after reducing
power to a GTE in response to a high lube oil supply temperature alarm,
the temperature continues to rise, your next step should be to __________.
continue to reduce
power
waterwash the
engine
shutdown the engine
check oil consumption
A
The divergent
area of the exhaust duct aids in what process?
Increasing the
volume of the exhaust gases.
Increasing the
velocity of the exhaust gases.
Decreasing the
volume of the exhaust gases.
Increasing the
pressure of the exhaust gases.
D
While vacuum is
being raised on the main unit and the turbine warmed, condensate is recirculated
to the main condenser to __________.
provide a condenser
vacuum seal
cool the main
condenser shell for better vacuum
maintain a proper
DC heater water level
ensure the condensation
of air ejector steam
A
For an emergency
stop of the rotor of a main turbine while underway at sea you should __________.
admit astern steam
to the turbine after securing the ahead steam
apply the prony
brake
tighten the stern
tube packing gland
secure all steam
to the turbine
A
How is lube oil
pressure provided to a turbo-generator when starting the unit in an automated
plant?
the hand-operated
or auxiliary lube oil pump
a line from the
other generator
a line from the
gravity tank
the main lube
oil pump
D
What type of gland
seal packing arrangement is shown in the illustrated turbine shaft gland?
Illustration SE-
Straight-through
labyrinth packing.
Straight-through
carbon packing.
Stepped carbon
packing.
Stepped labyrinth
packing.
B
What will be the
FIRST thing to occur if both the main and standby lube oil pumps failed
to operate on a geared main propulsion steam turbine operating at full sea
speed?
Vacuum will be
lost.
Ahead throttle
will close.
Shaft brake will
engage.
Lube oil sump
will overflow.
C
When starting
a turbine driven boiler feed pump, care should be taken to ensure that the
recirculating valve is open. Which of the following valves should be closed
when starting?
Pump suction valve
Turbine exhaust
valve
Pump discharge
valve
Turbine steam
supply valve
D
Which of the following
automatically actuates the overspeed tripping device installed on an auxiliary
turbine?
high back pressure
pneumatic force
hydraulic pressure
centrifugal force
C
Why is the cycle
efficiency higher in the intercooled-recuperated cycle as compared to a
simple cycle gas turbine? Illustration GT-
The intercooler
serves to increase the required high-pressure compressor power while the
recuperator utilizes waste heat from the exhaust to decrease turbine inlet
temperature.
The intercooler
serves to reduce the required high-pressure compressor power while the recuperator
utilizes waste heat from the exhaust to decrease turbine inlet temperature.
The intercooler
serves to reduce the required high-pressure compressor power while the recuperator
utilizes waste heat from the exhaust to decrease required fuel to achieve
the turbine inlet temperature.
The intercooler
serves to increase the required high-pressure compressor power while the
recuperator utilizes waste heat from the exhaust to increase turbine inlet
temperature.
C
Compressor characteristics
are normally summarized in the form of which of the following?
Venn diagram.
Straight line
graph.
Compressor map.
Spread sheet.
D
Accelerometers
are generally used on gas turbine engines to sense which of the following?
Rate of rotor
speed changes.
Gas generator
speed with respect to power turbine speed.
PLARA rate limited
feedback to the FSEE.
High frequency
vibration.
B
Displacement,
velocity and acceleration describe three types of which of the following?
Random Access
Memory.
Vibration sensors.
Filters.
Multiplexers.
D
In order to get
a ready indication for a normal start with a GE LM gas turbine engine,
what permissive(s) must be met?
Bleed air valve
must be closed.
GG speed must
be less than RPM and all engine trips reset.
Fuel supply pressure
must be greater than 8 psig
All of the above.
D
For the GE LM
gas turbine engine shown in the illustration, the 13th stage bleed air is
used for which of the following? Illustration GT-
Sump pressurization
and cooling.
Power turbine
balance piston cavity pressurization.
Power turbine
cooling.
High pressure
turbine 2nd stage nozzle cooling.
C
For the GE LM
gas turbine engine shown in the illustration, the HP turbine 2nd stage nozzle
vanes are cooled by which of the following? Illustration GT-
Frame vent bleed
air.
13th stage compressor
air.
16th stage compressor
air.
9th stage compressor
air.
D
For the GE LM
gas turbine engine shown in the illustration, the HP turbine 2nd stage blades
are cooled by convection, with the cooling air being discharged where? Illustration
GT-
Nose holes on
the leading edge.
Gill holes on
the side.
Trailing edge
slots.
Blade tips.
D
For the GE LM
gas turbine engine shown in the illustration, the HP turbine 1st stage nozzle
vanes are cooled by which of the following? Illustration GT-
8th stage compressor
air.
9th stage compressor
air.
13th stage compressor
air.
16th stage compressor
air.
D
On the GE LM
gas turbine engine, magnetic pickups are utilized for what purpose?
Determining gas
generator speed.
Calculating engine
torque.
Determining power
turbine speed.
All of the above.
D
In order to get
a ready indication for a normal start with a GE LM marine gas turbine,
what permissive(s) must be met?
Fuel supply pressure
must be greater than 8 psig
Bleed air valve
must be closed.
Gas generator
speed must be less than RPM and all engine trips reset.
All of the above.
D
In the marine
gas turbine engine shown in the illustration, the 9th stage bleed air is
used for which of the following? Illustration GT-
Compressor balance
piston cavity pressurization.
High pressure
turbine 2nd stage nozzle cooling.
Sump pressurization
and cooling.
Power turbine
cooling.
A
In the marine
gas turbine engine shown in the illustration, the 13th stage bleed air is
used for which of the following? Illustration GT-
High pressure
turbine 2nd stage nozzle cooling.
Power turbine
cooling.
Power turbine
balance piston cavity pressurization.
sump pressurization
and cooling
C
In the marine
gas turbine engine shown in the illustration, the HP turbine 2nd stage nozzle
vanes are cooled by which of the following? Illustration GT-
Frame vent bleed
air.
9th stage compressor
air.
13th stage compressor
air.
16th stage compressor
air.
B
As shown in the
illustration, the HP turbine 2nd stage blades are cooled by convection,
with the cooling air being discharged at which of the following? Illustration
GT-
Trailing edge
slots.
Blade tips.
Gill holes on
the side.
Nose holes on
the leading edge.
D
In the marine
gas turbine engine shown in the illustration, the HP turbine 1st stage nozzle
vanes are cooled by which of the following? Illustration GT-
8th stage compressor
air.
9th stage compressor
air.
13th stage compressor
air.
16th stage compressor
air.
B
On a vessel equipped
with propulsion gas turbines, the operators initial response to a high vibration
alarm should be which of the following?
Switch to the
secondary channel to confirm the alarm.
Reduce the engine
speed.
Wait for the harmonic
vibration to dampen out.
Change out the
vibration transducer.
C
The two main types
of compressor stall are known as what?
Flame out and
inlet temperature stall.
Over-speed and
overload stall.
Steady state and
transient.
Rapid rise and
temperature inversion.
C
Which of the following
could cause compressor stall?
Air flow over
the lower foil section becomes turbulent and destroys the pressure zone.
The angle at which
the hot gases strike the turbine rotor blades is too high.
The angle at which
the air strikes the compressor rotor blades is too high.
The angle at which
the air strikes the compressor rotor blades is too low.
D
How can compressor
stall be prevented?
Utilize a two-spool
compressor rotor.
Lowering the angle
of attack on the front stages.
Installing air
bleed valves in the middle of the compressor.
All of the above.
D
What is the term
given to the condition in which cyclic pressure changes result in a repetitive
failure and recovery of compressor air flow?
Laminar.
Turbulence.
Stall.
Surge.
B
When a compressor
is in a stall condition, what will happen to the combustor and turbine temperatures?
Slowly increase.
Rapidly increase.
Rapidly decrease.
Slowly decrease.
A
Compressor surge
is caused by which of the following factors?
Interrupted airflow.
Maximum fuel pressure.
Low ambient air
temperature.
Increased demand
for secondary air.
A
On a propulsion
marine gas turbine, if full power temperatures become excessive, what action
should the operator take?
Reduce power to
stay within limits.
Water wash the
engine.
Borescope the
engine.
No action is needed
until auto shutdown occurs.
D
If the lube oil
scavenge temperature exceeds 300 degrees Fahrenheit on the gas turbine engine
shown in the illustration, and reducing power does NOT bring the temperature
within limits, the operator should do which of the following? Illustration
GT-
Continue to operate
at the reduced power level.
Monitor the temperature
while continuing to operate.
Continue to reduce
power on the engine.
Shutdown the engine
and troubleshoot.
D
While standing
watch on a ship equipped with the gas turbine engine shown in the illustration,
a fire emergency stop is initiated when which of the following situations
occur? Illustration GT-
either the primary
or reserve GTM CO2 system activates
the GTM fire emergency
shutdown switch located on the module is activated
one of the UV
flame detectors is activated
All of the above.
D
When working with
gas turbine synthetic lube oil, which of the following safety measures should
always be observed?
thoroughly wash
any area of skin contact
avoid prolonged
inhaling of vapors
wear eye protection
and rubber gloves
All of the above.
D
When working in
or around intake areas, which of the following precautions should be taken?
Remove all loose
objects from your clothing.
Inspect the intake
for cleanliness.
Account for all
tools and equipment.
All of the above.
D
While underway
on a ship with gas turbine engines, the most likely indication of an engine
stall is which of the following?
Combustor temperature
increases.
A loud bang is
heard.
Engine fails to
accelerate.
All of the above.
D
Which of the following
is the most probable cause if, while underway, the main propulsion gas turbine
air intake blow-in doors open?
Exhaust pressures
are higher than normal.
Air inlet pressures
to the compressor are higher than normal.
Air inlet temperatures
to the compressor are higher than normal.
Ice has formed
on the air intakes.
A
In which of the
following ways can compressor surge cause excessive temperatures in the
turbine section?
By providing inadequate
secondary air
By overloading
the compressor
By providing excessive
combustion air
All of the above.
D
On a ship with
a marine gas turbine as shown in the illustration, a fire emergency stop
is initiated when __________. Illustration GT-
one of the UV
flame detectors is activated
either the primary
or reserve GTM CO2 system activates
the GTM fire emergency
shutdown switch located on the module is activated
All of the above.
A
On the marine
gas turbine engine shown in the illustration, what temperature should be
carefully monitored following a shutdown for an engine fire? Illustration
GT-
power turbine
inlet
fuel manifold
combustor liner
compressor discharge
B
If a fire is detected
in a main propulsion gas turbine enclosure, which of the following would
occur prior to automatic release of the fire extinguishing agent?
Cooling water
to the enclosure would be secured.
If open, bleed
air valves would be closed.
Water wash valves
to the engine would be opened.
Reduction gear
oil systems would be secured.
C
If after reducing
power to a gas turbine engine in response to a high lube oil supply temperature
alarm, the temperature continues to rise, your next step should be which
of the following?
Check oil consumption.
Continue to reduce
power.
Shutdown the engine.
Water wash the
engine.
A
During an operation
of a main propulsion gas turbine, the engine shuts down. Which of the following
is the most probable reason for the shutdown?
High vibration
on the gas generator.
High lube oil
temperature.
Low fuel supply
temperature.
Low sump oil level.
D
Which of the following
is the most likely cause for the main propulsion gas turbine engine tripping
during start up?
Inlet air ice
detection.
High oil filter
differential pressure.
Low sump oil level.
Failure to achieve
the minimum rpm in a certain period of time.
B
On the marine
gas turbine shown in the illustration, the gas generator speed sensor is
located where? Illustration GT-
At the compressor
inlet.
On the accessory
gearbox.
Within the high
pressure turbine.
Within the compressor.
B
What are two common
methods of power turbine blade retention?
Riveting and fir-free
Bulb and dovetail
Fir-tree and bolting
Bulb and bolting
A
Which of the following
is a feature of a power turbine blade that is not found on a high temperature
turbine blade?
Interlocking shrould
tips.
Solid blades.
Dovetail roots.
Bulb roots.
C
Aboard ship, single-shaft
gas turbines are used mostly as prime movers for which of the following
applications?
Multi-screw ships
Single-screw ships
Generators
Auxiliary power
units
C
Which of the following
is an advantage of a single-shaft gas turbine engine compared to a split-shaft
gas turbine engine?
Lower starting
torque
Reversible
Fewer moving parts
Better fuel economy
B
In a single shaft,
cold-end drive gas turbine, the power output speed has what relationship
to the speed of the compressor?
It varies independently
of compressor speed.
It is the same
or in a direct relationship through reduction gears.
It is in an inverse
relationship through reduction gears.
None of the above.
C
In a twin-spool
turbine, secondary air is most essential for cooling in what section?
HP compressor.
LP turbine.
HP turbine.
LP compressor.
C
What type of starter
is commonly used on smaller gas turbine engines?
Pneumatic
Air turbine
Electric
Hydraulic
B
Accelerating the
compressor to the self sustaining speed of the engine is the function of
which of the following components?
Compressor extension
shaft
Starter
PT shaft
Mechanical driveshaft
A
What type of engine
starter motor is commonly found on the marine gas turbine shown in the illustration?
Illustration GT-
Hydraulic motor
AC synchronous
motor
AC induction motor
DC series wound
electric motor
D
Which of the following
components removes the oil from the transfer gearbox?
Lube oil storage
and conditioning assembly
Air-Oil separator
Duplex filter
assembly
Lube and scavenge
pump
A
What is the purpose
of the air/oil separator shown in the illustration of the gas turbine lube
oil system? Illustration GT-
Minimize oil consumption
by separating oily vapors being vented to the atmosphere.
Reduce oil foaming.
Maintain oil pressure
in the sumps.
All of the above.
B
all or roller
antifriction bearings are used to support gas turbine rotors for all EXCEPT
which of the following?
To accommodate
both axial and radial loads
To offer maximum
rotational resistance
To facilitate
precision alignment
To withstand high
momentary overloads
A
What type of air
seal is used in the sump and turbine areas of a gas turbine engine?
Labyrinth-Honeycomb
Lip Type
Fishmouth
Pneumatic carbon
ring
D
What type of air
seal is used in the combustor and turbine midframe of a gas turbine?
Pneumatic carbon
ring
Labyrinth-Honeycomb
Lip-Type
Fishmouth
D
What type of seal
is used in the gearbox of a gas turbine engine?
Lip-type
Fishmouth
Labyrinth-Windback
Carbon ring
B
What is the purpose
of the spring in a lip-type oil seal?
To remove burrs
and dirt from the shaft
To keep the neoprene
snugly fit around the shaft
To seal against
maximum fluid pressure
To prevent air
from entering the sump
C
Which of the following
statements is true concerning the fuel oil ignition system of the gas turbine
engine shown in the illustration? Illustration GT-
The igniters will
only energize if the exhaust gas temperature falls below a preset value.
The igniters will
de-energize when the power turbine exceeds a preset RPM.
The igniters will
de-energize when the gas generator exceeds a preset RPM.
The igniters remain
energized throughout the normal operation of the engine.
C
How many shock
mounts are used to secure the GE LM gas turbine enclosure to the ship's
foundation?
16
24
32
40
D
Where are the
carbon dioxide nozzles located in the GE LM gas turbine enclosure?
Above and below
the combustor section
On either side
of the PT
Above the compressor
On the cross beam
under the compressor front frame
C
What type of combustor
is used by the GE LM gas turbine?
Can-annular
Can
Annular
Cannular
D
The gas generator
section of the GE LM gas turbine is composed of all of the following
components EXCEPT which of the following?
FOD screen
Bellmouth
Two stage HP turbine
Six stage LP turbine
B
The struts of
the GE LM compressor front frame provide passages for all of the following
mediums EXCEPT which of the following?
Scavenge oil
Fuel oil
Seal-pressurization
air
Lube oil
C
What is the primary
purpose of the diffuser and distributor on the GE LM gas turbine?
To provide uniform
air flow to the compressor
To provide even
temperature distribution at the compressor
To provide uniform
airflow to the combustor
To provide uniform
airflow to the turbine
B
Which of the following
components prevent(s) objects smaller than 1/4 inch from entering the GE
LM gas turbine engine?
Inlet louvers
FOD screens
Centerbody
Demister pads
C
How is the HP
turbine rotor of the GE LM gas turbine cooled?
By synthetic lube
oil
By the ship's
service seawater cooling system
By a continuous
flow of compressor discharge air
By an air to air
heat exchanger
C
What is the primary
function of the main fuel control on the GE LM gas turbine engine?
To control fuel
pump inlet pressure
To control stator
vane angle and bleed air discharge
To control stator
vane angle and GG speed
To control fuel
temperature
D
As shown in the
illustration of a gas turbine fuel oil system, when the engine fuel oil
valves are de-energized, the remaining fuel left in the system is recirculated
back to which of the following? Illustration GT-
Day tank.
High pressure
relief valve.
Fuel purge manifold.
Fuel pump inlet.
B
What is the purpose
of the GE LM gas turbine enclosure heater?
To ensure enclosure
temperature is maintained at 145 degrees F
To ensure fuel
viscosity is maintained while the GTE is secured
To warm up the
enclosure for maintenance personnel
To increase inlet
air temperature
B
How many stages
are in the HP turbine of the GE LM gas turbine engine?
One
Two
Three
Four
B
The power turbine
(PT) of the GE LM gas turbine engine has a total of how many stages?
Four
Six
Seven
Eight
C
A total of how
many shock mounts are used to secure the LM enclosure to the ship's
foundation?
16
24
32
40
A
Where are the
CO2 nozzles located in the GE LM gas turbine enclosure?
On the cross beam
under the compressor front frame
Above and below
the combustor section
On either side
of the PT
Above the compressor
D
What type of combustor
is used by the GE LM gas turbine engine?
Can-annular
Can
Cannular
Annular
D
The gas generator
section of the GE LM gas turbine engine is composed of all of the following
components EXCEPT for which of the following?
Bellmouth
Two stage HP turbine
FOD screen
Six stage LP turbine
A
The struts of
the compressor front frame provide passages for all of the following mediums
EXCEPT for which of the following?
Fuel oil
Scavenge oil
Seal-pressurization
air
Lube oil
B
What is the primary
purpose of the diffuser and distributor on the GE LM gas turbine engine?
To provide even
temperature distribution at the compressor
To provide uniform
airflow to the combustor
To provide uniform
air flow to the compressor
To provide uniform
airflow to the turbine
C
Which of the following
components prevent(s) objects smaller than 1/4 inch from entering the engine?
Centerbody
Demister pads
FOD screens
Inlet louvers
D
How is the HP
turbine rotor of the GE LM gas turbine engine cooled?
By the ship's
service seawater cooling system
By synthetic lube
oil
By an air to air
heat exchanger
By a continuous
flow of compressor discharge air
B
What is the primary
function of the main fuel control on the GE LM gas turbine engine?
To control fuel
temperature
To control stator
vane angle and GG speed
To control fuel
pump inlet pressure
To control stator
vane angle and bleed air discharge
A
As shown in the
illustration of a gas turbine fuel oil system, when the engine fuel oil
valves are de-energized, the remaining fuel left in the system is recirculated
back to which of the following? Illustration GT-
fuel pump inlet
high pressure
relief valve
day tank
fuel purge manifold
A
Which of the following
statements is true about the "lockout control" on a synchronous
self-shifting (SSS) clutch?
Permits operation
of the GTE without the rotation of the main reduction gear.
It is an automatically
operated control.
The mechanism
is incorporated into the input assembly of the clutch.
None of the above.
B
How is the clutch
shown in the attached illustration engaged? Illustration GT-
Pneumatic pressure
from the compressor engages the clutch.
Clutch engages
automatically when input shaft flange is rotating faster than the output
assembly.
Clutch is engaged
manually prior to start up.
Clutch engages
automatically once the output assembly begins rotating.
C
How do you manually
lockout an SSS clutch?
Remove the SSS
clutch locking pawls.
Calculate the
engagement speed of the SSS clutch.
Using the special
wrench provided.
Using air pressure.
A
The term "lockout"
on the Synchro-Self-Shifting (SSS) clutch system means that the __________.
SSS clutch will
not engage
shaft will not
rotate above 10 RPM's
reduction gear
will not rotate
shaft will not
rotate
C
The bleed air
surge relief valve differs from a normal relief valve in which of the following
ways?
Opens completely
at a specified lift pressure and then immediately closes.
Closed completely
at a specified lift pressure and slowly opens as system pressure drops.
Opens completely
at a specified lift pressure and remains open until a preset pressure is
attained.
Closes completely
at a specified pressure and remains closed.
B
The purpose of
the main reduction gear in a marine gas turbine propulsion installation
is which of the following?
Increase gas turbine
speed to engage the clutch.
Transfer high-speed
gas turbine rotation to low-speed propeller rotation.
Transfer low-speed
gas turbine rotation to high-speed propeller rotation.
Reduce gas turbine
speed to engage the cutch.
B
What type of main
reduction gear arrangement prevents independent axial and rotational movement
of the pinions?
Independent suspension
Locked train
Unlocked train
Hydraulic suspension
D
The main reduction
gear performs which of the following functions?
It transfers low-speed
gas turbine rotation to high-speed propeller rotation
It increases gas
turbine speed for clutch engagement
It reduces gas
turbine speed for clutch engagement
It transfers high-speed
gas turbine rotation to low-speed propeller rotation
A
What feature is
commonly used on articulated reduction gear arrangements for the correction
of misalignment between the 1st reduction gear and the 2nd reduction pinions?
Quill shafts.
Fixed block pads.
Torsion pads.
Locked train shims.
D
Rotation of the
Controllable Pitch Propeller (CPP) blades is achieved through axial movement
of what component in the hub body assembly?
The servomotor
piston
The sliding block
The crankpin ring
The crosshead
A
In a typical gas
turbine propulsion plant, the main thrust bearing directly positions which
part(s) of the main reduction gear?
Low-speed gear
High-speed gear
Low-speed pinions
High-speed pinions
C
What does the
term "lock-out" of a synchro-self-shifting (SSS) clutch system
mean? Illustration GT-
Reduction gear
will not rotate.
Shaft will not
rotate above 10 RPM.
SSS clutch will
not engage.
Shaft will not
rotate.
B
How is the clutch
shown in the attached illustration engaged? Illustration GT-
Pneumatic pressure
from the compressor engages the clutch.
Clutch engages
automatically when input shaft flange is rotating faster than the output
assembly.
Clutch engages
automatically once the output assembly begins rotating.
Clutch is engaged
manually prior to start up.
D
On a gas turbine
powered vessel equipped with a synchro self shifting (SSS) clutch, you are
preparing for a power turbine over speed test. What would be an important
action to take prior to starting the engine?
Remove the SSS
clutch locking pawls.
Calculate the
engagement speed of the SSS clutch.
Engage the SSS
clutch using air pressure.
Manually lockout
the SSS clutch from engaging using the special wrench provided.
A
What type of main
reduction gear arrangement prevents independent axial and rotational movement
of the pinions?
Locked train
Hydraulic suspension
Unlocked train
Independent suspension
A
The purpose of
the main reduction gear in a marine gas turbine propulsion installation
is which of the following?
Transfer high-speed
gas turbine rotation to low-speed propeller rotation.
Reduces gas turbine
speed to engage the clutch.
Transfer low-speed
gas turbine rotation to high-speed propeller rotation.
Increases gas
turbine speed to engage the clutch.
A
The main thrust
bearing directly positions which part(s) of the main reduction gear?
Bull gear.
Low-speed pinion.
High-speed pinion.
High-speed gear.
D
The lubrication
principal used by the Kingsbury thrust bearing is which of the following?
Cylinder-shaped
oil film.
Free sliding oil
film.
Square-shaped
oil film.
Wedge-shaped oil
film.
C
When performing
a static check to determine tooth contact, you should use which of the following
compounds to coat the gear teeth?
Copper sulfate.
An indelible marker.
Prussian Blue.
Persian Blue.
D
Gear backlash
is best described as which of the following?
Clearance of the
gears operating in parallel.
Clearance of the
gears that do not mesh.
Radial play between
the pinion teeth and bearings.
Play between the
surfaces of the teeth in mesh.
A
In cases where
both the pinion and gear teeth of the main reduction gear have been slightly
indented by foreign material, what action should you take?
Both the pinion
and gear should be relieved of all raised metal around the indentation.
Closely monitor
the damage to see if it spreads.
Remove the foreign
material that caused the indentation and return the unit to service.
Replace both the
pinion and gear.
D
The fuel oil system
of a gas turbine engine provides all EXCEPT which of the following?
Acts as a hydraulic
medium to actuate the fuel control
Provides accurately
metered fuel for combustion
Controls the angle
of the variable stator vanes
Acts as a cooling
medium for the lube oil cooler
C
Gas turbine fuel
manifold pressure is established by which of the following actions?
Closing the fuel
recirculating valve.
Starting the fuel
service pumps on low speed.
Rotating the gas
generator.
Starting the fuel
service pumps on high speed.
D
The secondary
passages on the gas turbine engine fuel nozzles shown in the illustration
are designed to open at approximately what pressure? Illustration GT-
30 PSIG
130 PSIG
230 PSIG
330 PSIG
B
How many fuel
igniters would be installed on the marine gas turbine engine shown in the
illustration? Illustration GT-
1
2
3
4
D
The fuel oil back
pressure regulator on the fuel system shown in the illustration, returns
fuel to the which of the following? Illustration GT-
Booster pump suction.
Purge valve discharge.
Fuel oil day tank.
Booster pump discharge.
D
The main fuel
control module used on a marine gas turbine engine as shown in the illustration,
is responsible for managing which function(s)? Illustration GT-
deceleration schedule
variable stator
vane feedback lever
acceleration schedule
All of the above.
D
The purpose of
the air shroud (swirl cup) around the tip of the fuel nozzle of an GE LM
gas turbine engine is which of the following?
cool the nozzle
tip
promote air turbulence
promote air/fuel
mixing
All of the above.
C
A fuel analysis
report for a gas turbine propelled vessel indicates a calcium level in excess
of 0.5 ppm. High calcium levels in distillate fuels for gas turbines can
cause which of the following?
Abrasive wear
in the compressor section of the turbine.
Clogged fuel filters
in the fuel service system.
Calcium deposits
which can clog cooling holes in the turbine section.
Corrosion in the
combustor section of the turbine.
A
During an operation
of a gas turbine equipped with an intercooler and recuperator, a low combustion
air temperature to the combustor section could be caused by which of the
following?
Low exhaust temperature.
High fuel pressure
to the combustor section.
Low water pressure
to the intercooler.
High exhaust temperature.
D
A gas turbine
engine is experiencing a high rate of corrosion in the hot section of the
engine. Which of the following fuel contamination issues could be associated
with this problem?
High ash content
in the fuel.
High particle
content in the fuel.
Low pour point
of the fuel.
High saltwater
content in the fuel.
A
The gas generating
sections of marine gas turbine engines are based on which of the following?
Aircraft jet engines.
Radial piston
engines.
Oil-fired auxiliary
boilers.
Free piston engines.
B
Compared to other
types of engines, what is the biggest advantage of a gas turbine engine?
Simplicity of
the control circuits.
Highest power-to-weight
ratio.
Low power-to-weight
ratio.
Simplicity of
installation.
D
An open cycle
gas turbine engine is best described by which of the following statements?
Energy is neither
created nor destroyed and the cycle is therefore perpetual.
Energy is added
externally.
Working fluids
are taken in, transformed, and then recuperated.
Working fluids
are taken in, transformed, and then discarded.
A
What is the difference
between an open cycle and a closed cycle gas turbine engine?
An open cycle
discards the working fluid and a closed cycle retains the working fluid.
A closed cycle
heats the working fluid from an internal source and an open cycle uses an
external source for heating the working fluid.
There is no difference
because both use the same working fluid.
An open cycle
retains the working fluid and a closed cycle discards the working fluid.
D
The Brayton Cycle
is a series of events best described by which of the following statements?
Intake, pressurization,
ignition, exhaust.
Intake, compression,
combustion, explosion, exhaust.
Intake, decompression,
combustion, expansion, exhaust.
Intake, compression,
combustion, expansion, exhaust.
D
Why is a gas turbine
considered to operate on the Brayton cycle?
Combustion causes
large increase in pressure.
Combustion causes
no increase in volume.
Combustion causes
an increase in total mass flow.
Combustion occurs
with no increase in pressure.
D
The thermal energy
added to the gas as it flows through the combustion section has what effect
on the gas?
Increase pressure.
Decrease volume.
Decrease pressure.
Increase volume.
D
In a gas turbine,
the air charge is permitted to be compressed adiabatically by what factor,
process, or condition?
Rapid heat transfer
Low-compression
ratio
Interstage cooling
Speed of the process
C
Why is the cycle
efficiency higher in the intercooled-recuperated cycle as compared to a
simple cycle gas turbine? Illustration GT-
The intercooler
serves to increase the required high-pressure compressor power while the
recuperator utilizes waste heat form the exhaust to decrease turbine inlet
temperature.
The intercooler
serves to increase the required high-pressure compressor power while the
recuperator utilizes waste heat form the exhaust to increase turbine inlet
temperature.
The intercooler
serves to reduce the required high-pressure compressor power while the recuperator
utilizes waste heat form the exhaust to decrease required fuel to achieve
the turbine inlet temperature.
The intercooler
serves to reduce the required high-pressure compressor power while the recuperator
utilizes waste heat form the exhaust to decrease turbine inlet temperature.
B
A gas turbine
engine in which exhaust gas heat energy is added to the compressor air charge
before entering the combustor, is classified as which of the following?
Reheat cycle.
Regenerative cycle.
Combined cycle.
ICR cycle.
C
The acronym CDP
stands for which of the following?
Choke Down Point.
Coupling Disassembly
Point.
Compressor Discharge
Pressure.
Compressor Discharge
Pyrometer.
A
The acronym FOD
stands for which of the following?
Foreign Object
Damage.
Fuel Override
Demand.
Flow Offset Design.
Fuel Oil Discharge.
D
The acronym MFC
represents which of the following?
Manifold Fuel
Control.
Maritime Fuel
Congress.
Mid Frame Compressor.
Main Fuel Control.
C
The acronym VSV
represents which of the following?
Variable Speed
Valve.
Vibration Stator
Vanes.
Variable Stator
Vane.
Vibration Shutdown
Valve.
C
The acronym GG
represents which of the following?
Vibration-Gas
Generator
Temperature-Gas
Generator
Gas Generator
Speed-Gas Generator
A
Boyle's law can
best be defined as which of the following?
The volume of
an enclosed gas varies inversely with the applied pressure, provided the
temperature remains constant.
If the pressure
is constant, the volume of an enclosed gas varies indirectly with absolute
temperature.
A body at rest
tends to remain at rest.
None of the above.
A
In the operation
of a marine propulsion gas turbine, kinetic and thermal energy required
to drive the main propeller shaft are extracted by which of the following?
Power turbine.
COWL diffuser
Multi-stage compressor.
Variable Stator
Vane actuators.
C
On the gas turbine
shown in the illustration, which of the following best describes the main
principle of operation of the component contained within the area labeled "C"?
Illustration GT-
Bernoulli's Law
of Divergency
Newton's Law of
Motion
Combustion at
a constant pressure
Otto Cycle
D
A gas turbine
that has a regenerator between the compression and combustion sections in
which exhaust gas heat energy is added to the air charge is classified as
what type of engine?
Semi-open cycle
engine.
Closed cycle engine.
Open cycle engine.
Semi-closed cycle
engine.
C
The term used
to describe a gas turbine in which air drawn from the atmosphere passes
through the engine only once is which of the following?
Uni-cycle.
Closed cycle.
Open cycle.
Semi-closed cycle.
D
The term used
to describe a gas turbine in which the turbine exhaust passes through a
cooler and back to the compressor inlet is which of the following?
Uni-cycle.
Twin cycle.
Open cycle.
Closed cycle.
D
In a regenerative
or recuperative gas turbine cycle configuration, the heat of the turbine
exhaust gas is used to do what?
Heat the LP compressor
discharge air before entering the HP compressor inlet.
Heat the intake
air to the compressor.
Heat the combustor
discharge gas before entering the turbine.
Heat the compressor
discharge air before it enters the combustor.
D
What type of gas
turbine cycle configuration is shown in the illustration? Illustration GT-
Recuperative type.
Simple type.
Intercooled type.
Intercooled-recuperated
type.
D
Which of the following
statements about the intercooled-recuperated gas turbine cycle is true?
Illustration GT-
Intercooler serves
to increase the required high-pressure compressor power, while the recuperator
utilizes waste heat form the exhaust to increase turbine inlet temperature.
Intercooler serves
to increase the required high-pressure compressor power, while the recuperator
utilizes waste heat form the exhaust to decrease turbine inlet temperature.
Intercooler serves
to reduce the required high-pressure compressor power, while the recuperator
utilizes waste heat form the exhaust to decrease turbine inlet temperature.
Intercooler serves
to reduce the required high-pressure compressor power, while the recuperator
utilizes waste heat form the exhaust to decrease required fuel to achieve
turbine inlet temperature.
D
For the same amount
of available power, how does a low speed two-stroke diesel engine compare
to a recuperated gas turbine configuration?
The two-stroke
diesel engine would burn more fuel and the particulate and nitrogen oxide
(NOx) levels in the exhaust would be higher than that of a recuperated gas
turbine configuration
The two-stroke
diesel engine would burn less fuel and the nitrogen oxide (NOx) levels in
the exhaust would be much lower than that of a recuperated gas turbine configuration.
The two-stroke
diesel engine would burn more fuel than a recuperated gas turbine; however,
the particulate and nitrogen oxide (NOx) levels in the exhaust would be
lower.
The two-stroke
diesel engine would burn less fuel than a recuperated gas turbine, however,
the levels of particulate and nitrogen oxide (NOx) levels in the exhaust
would be higher.
A
Which of the following
wrenches should NOT be used while working on a gas turbine?
Adjustable wrench.
Box wrench.
Flare nut wrench.
Crowfoot wrench.
B
Wrenches that
are recommended for use on gas turbine engines should be plated with which
of the following elements?
Bronze
Nickel
Carbon
Silver
D
Which of the following
instruments is designed to help you when performing an internal inspection
of the gas turbine engine?
Telescope
Stroboscope
Oscilloscope
Borescope
D
All clock positions,
engine references, and enclosure references apply to viewing the gas turbine
engine shown in the illustration from which of the following locations?
Illustration GT-
Right side of
the compressor to the left side.
Left side of the
power turbine to the right side.
Intake end, looking
toward the exhaust end.
Rear (exhaust
end), looking toward the intake end.
D
Routine water
washing of the gas turbine engine compressor shown in the illustration,
is usually performed while operating under which of the following conditions?
Illustration GT-
At 25% power.
At 75% power.
At full power.
With the starter
motor drive.
A
When removing
the gas turbine engine as shown in the illustration, how is the engine removal
accomplished? Illustration GT-
By removing the
inlet screen, barrier wall and module front panel, then installing the rails
and moving the engine into the engine room and up through the soft patch
to the main deck.
By removing the
exhaust boot, HSCS and PT, then lifting the engine up the exhaust stack.
By removing the
inlet screen and barrier wall, then installing the rails and lifting the
engine out through the inlet duct.
By removing the
upper half casing and separately lifting out the compressor and power turbine
rotors.
C
You are preparing
for a borescope inspection of a gas turbine engine. Prior to the inspection
it is recommended that you do which of the following?
Water wash both
the compressor and the power turbine.
Water wash the
power turbine.
Water wash the
compressor.
Not water wash
the engine prior to the inspection.
B
To manually rotate
the GE LM gas turbine engine, you should use which of the following
tools?
18-inch long 1/2-inch
drive socket wrench.
A socket wrench
with an 18-inch long 3/4-inch drive extension.
18-inch long 3/4-inch
drive socket wrench.
A socket wrench
with an 18-inch long 1/2-inch drive extension.
B
When conducting
a borescope inspection, you must be aware of all of the following factors
EXCEPT which?
The inspection
areas and ports.
The engineers
experience.
The internal reference
points.
The limitations
of your equipment.
A
You are preparing
for a borescope inspection of a GE LM gas turbine engine. You are reviewing
the correct geometric orientation nomenclature which includes which of the
following?
All references
left, right, and radial are orientated as viewed from aft looking forward
on the engine.
All references
left, right, and radial are orientated as viewed from forward looking aft
on the engine.
All references
are made from the combustor section, forward to the hp turbine and aft to
the power turbine.
All references
are made from the combustor section, aft to the hp turbine and forward to
the power turbine.
A
The six borescope
ports located in the compressor rear frame casing of the marine propulsion
gas turbine shown, can be used to inspect all EXCEPT which of the following
components? Illustration GT-
14th stage compressor
blades.
Fuel nozzles.
Combustor.
1st stage turbine
nozzle
B
On an GE LM
gas turbine powered vessel you are conducting a borescope inspection of
the compressor. What is used on each compressor stage as a reference for
indexing the blades?
The IGV actuator.
The locking lug
blades.
Witness marks
center punched on the #1 nozzle and blade.
Scribe marks located
on the stator and rotor diaphragm.
A
Zero reference
for the GE LM gas turbine engine is established by the use of which
of the following engine components?
Locking lug blades.
Vane blades.
Carboloy blade
pads.
Vane shrouds.
D
When conducting
a borescope inspection of the compressor, why can airfoil and tip cracks
be difficult to detect?
Rotating the rotor
too fast.
Borescope optics
have deteriorated.
The cracks are
generally tight and shallow in depth.
All of the above.
A
When inspecting
the combustion section of a gas turbine engine, what wattage light source
should you use?
watt.
750 watt.
500 watt.
250 watt.
B
In a gas turbine
propulsion installation, the typical control system is designed to perform
which of the following three functions?
Operational control,
speed control, and braking.
Operational control,
safety control, and monitoring.
Pneumatic, hydraulic,
and electric control.
Pneumatic control,
electric control and monitoring.
C
A magnet pickup
typically produces what type of signal output?
high current
steady DC voltage
voltage pulse
pure sine wave
B
When auto starting
a gas turbine engine similar to the one shown in the illustration, a "False
Start" indication will initiate if which of the following conditions
occurs? Illustration GT-
The gas generator
rotor fails to reach a preset RPM after the power turbine begins to rotate.
The gas generator
rotor fails to reach a preset RPM after the starting motor has been energized
for a preset interval.
Power Turbine
outlet temperature fails to reach a preset value.
The power turbine
fails to reach a preset RPM after the gas generator reaches a preset RPM.
B
During an auto-start
sequence on the marine gas turbine control console shown in the illustration,
what would be the correct order of events required to occur after the start
sequence begins? Illustration GT-
NGG reaches idle
RPM, Power turbine reaches ignition RPM, gas temperature greater than 400
degrees F.
NGG reaches ignition
RPM, gas temperature greater than 400 degrees F, NGG reaches idle RPM
Power turbine
reaches ignition RPM, gas temperature greater than 400 degrees F, Power
turbine reaches idle RPM
Power turbine
reaches ignition RPM, gas temperature greater than 400 degrees F, NGG reaches
idle RPM
D
A turbine stage
is represented by which of the following components and in which order?
One set of rotating
blades, one set of stationary vanes.
One set of rotating
vanes, one set of stationary blades.
Two sets of stationary
vanes, one set of rotating blades.
One set of stationary
vanes, one set of rotating blades.
D
The turbine nozzles
convert heat and pressure energy to velocity energy by means of which of
the following?
Deflection process.
Convergent-Divergent
Process.
Divergent process.
Convergent process.
D
In the operation
of a marine propulsion gas turbine, kinetic and thermal energy required
to drive the main propeller shaft are extracted by which of the following?
Multi-stage compressor.
Combustor.
Exhaust gas.
Power turbine.
C
How do the high-velocity
high-temperature gases cause the gas turbine rotor to rotate?
By creating a
low-pressure area before the rotor.
By converting
the high-velocity gas to low-velocity gas.
By transferring
velocity energy and thermal energy to the turbine blades.
By increasing
the velocity of the gases.
A
What are the two
principle functions of the turbine nozzle guide vanes?
Convert the heat
energy of the hot gases into kinetic energy and direct the flow of gases
to the turbine rotor blades.
Convert the potential
energy of the hot gases into heat energy and direct the flow of gases to
the turbine rotor blades.
Convert the heat
energy of the hot gases into potential energy and direct the flow of gases
to the compressor rotor blades.
Convert the heat
energy of the hot gases into potential energy and direct the flow of gases
to the turbine rotor blades.
D
The circle of
turbine stationary vanes that convert pressure and thermal energy to velocity
energy and direct the combustion gases in the direction of turbine wheel
rotation is referred to as what?
Rotor assembly.
Diffuser assembly.
Compressor assembly.
Nozzle assembly.
D
What method is
utilized to allow turbine nozzle blades to withstand high inlet temperatures?
Laser cooling
Thermoelectric
cooling
Water cooling
Air cooling
C
Which of the following
designs is the most satisfactory method for attaching turbine blades to
the rotor disk?
Pinning design.
Locking tab design.
Fir-tree design.
Retaining ring
design.
A
Turbine disks
are commonly attached to the shaft by which of the following methods?
Bolted or welded.
Locking tabs or
retaining rings.
Pinned or Locking
Tabs.
Riveted or pinned.
C
HP turbine blades
are generally cooled by which of the following methods?
Compressed air
entering the tip and exiting the root.
Cooling water
entering the tip and exiting the root.
Compressed air
entering the root and exiting the tip.
Cooling water
entering the root and exiting the tip.
B
To keep the exit
pressures relatively constant across a HP turbine blade, which type of construction
is generally utilized?
Curtis.
Impulse-Reaction.
Impulse.
Rateau.
A
Assuming you maintain
the same power output, how will a decrease in the compressor inlet air temperature
effect a gas turbine engine's efficiency and fuel consumption?
Efficiency will
increase and fuel consumption will decrease.
Efficiency will
decrease and fuel consumption will increase.
Efficiency and
fuel consumption will not be affected by a change in inlet air temperature.
Efficiency and
fuel consumption will both increase.
C
On a gas turbine
engine, a high outside air temperature can cause high turbine inlet temperature,
low mass/weight of airflow through the turbine, and which of the following
conditions?
A requirement
for less energy to achieve adequate compression
Cooler exhaust
gas temperature
A requirement
for more energy to achieve adequate compression
None of the above
D
Assuming that
the turbine inlet temperature of a gas turbine engine remains constant,
which of the following operating parameter changes would be noted with an
increase in the compressor inlet air temperature?
The mass air flow
through the gas turbine would increase.
The power turbine
output increases due to hot inlet air requiring less fuel to be heated to
the same turbine inlet temperature.
The exhaust temperature
would drop significantly.
The gas turbine
power would drop due to reduced mass air flow.
A
What action should
you take if full power vibration limits are exceeded on a gas turbine engine?
Reduce power to
stay within limits.
Borescope the
engine.
No action is needed.
Water wash the
engine.
C
What is the designed
compressor pressure ratio of the gas turbine compressor rotor shown in the
illustration? Illustration GT-
10 to 1
12 to 1
16 to 1
20 to 1
A
The two main types
of "compressor" stalls are known as which of the following?
Steady state and
transient.
Over-speed and
overload stall.
Flame out and
inlet temperature stall.
Rapid rise and
temperature inversion.
A
What design feature
is incorporated into the main propulsion gas turbine to eliminate compressor
surge?
Variable compressor
stator vanes are used.
The governor adjusts
the fuel to maintain the turbine inlet temperature constant.
The governor maintains
the compressor turbine speed constant.
Fuel modulating
function is incorporated into the governor control system.
D
To prevent overheating
of the illustrated turbine blade, which of the following fluids is circulated
through it via the shaped internal passages? Illustration GT-
Cooling water.
Cooling oil.
External compressed
air.
Bleed air.
B
A gas turbine
engine's main lube oil system pump check valve serves to maintain system
prime and perform what other function?
To increase system
pressure.
To prevent reverse
flow of oil through a secured pump.
To return oil
to the main reduction gear sump.
None of the above.
D
When the main
reduction gear lube oil system is secured, which of the following components
maintains the air within the casing at less than 35 percent relative humidity?
Rehumidifier
Precipitator
Reciprocator
Dehumidifier
C
The lube oil scavenge
pressure on the marine gas turbine shown in the illustration is sensed by
which of the following? Illustration GT-
Manometer.
RTD.
Transducer.
Probe.
B
For the gas turbine
engine lube oil system shown in the illustration, what is the purpose of
the lube oil supply check valves? Illustration GT-
Keep the lube
oil lines in the engine primed.
Prevent lube oil
contained in the LO storage and conditioning tank from draining into gearboxes
and sumps.
Prevent the lube
oil and scavenge pump from losing its prime.
All of the above.
D
How is the lube
oil supplied to each bearing in a gas turbine engine controlled?
Regulating valve.
Flow divider.
Lube oil pump.
Calibrated orifice.
A
The lube oil system
shown in the illustration, is designed to lubricate the main bearings by
what principle? Illustration GT-
Spray lubrication
with dry sumps.
Totally submerged
oil bath.
Splash lubrication.
Self-contained
partial oil bath.
B
On the gas turbine
engine lube oil system shown in the illustration, air and oil are primarily
separated in the air/oil separator through the use of which of the following?
Illustration GT-
Filter
Impeller
Heater
Strainer
B
On the marine
gas turbine engine shown in the illustration, the 8th stage bleed air is
used for which of the following? Illustration GT-
Power turbine
balance piston cavity pressurization.
Lube oil sump
pressurization and cooling.
High pressure
turbine 2nd stage nozzle cooling.
Power turbine
blade cooling.
B
As shown in the
illustration, what is the purpose of pressurizing the main bearing lube
oil sumps on a typical marine gas turbine? Illustration GT-
Provides uniform
lube oil distribution around the bearing.
Minimizes oil
leakage from the rotor shaft.
Increases lube
oil penetration.
Assist in cooling
the lube oil.
D
The lube oil system
shown in the illustration, consists of which of the following sub-systems?
Illustration GT-
Lube oil scavenging.
Sump venting.
Lube oil supply.
All of the above.
D
Which of the following
components are installed in the lube oil system shown in the illustration?
Illustration GT-
pressurized sumps
air/oil separators
pressurized supply
lines with separate scavenging return lines
All of the above.
D
How many lube
oil sumps are installed on the marine gas turbine engine shown in the illustration?
Illustration GT-
1
2
3
4
A
Which of the following
is true concerning the main engine lube oil system of the marine gas turbine
shown in the illustration? Illustration GT-
The system includes
a single combined lube oil supply and scavenge pump.
The lineshaft
bearing lubrication system is provided for by the LOSCA.
Lubrication is
provided for the main reduction gears through the transfer gearbox.
All of the above.
C
What type of main
lube oil supply and scavenging pump is installed on the marine gas turbine
engine shown in the illustration? Illustration GT-
Reciprocating
piston.
Flexible diaphragm.
Vane.
Centrifugal.
A
Which of the following
is the most probable cause for the sump oil to be excessively aerated on
an aero-derivative main propulsion gas turbine engine?
The air oil separator
is not functioning properly.
Air inlet temperatures
to the compressor are higher than normal.
The compressor
discharge pressure is lower than normal.
Exhaust pressures
are lower than normal.
D
Your first step
in response to a gas turbine engine high lube oil sump temperature alarm
would be which of the following?
Check the oil
filter differential pressure.
De-couple the
engine from the main reduction gear.
Check the oil
pressure to the sump.
Reduce engine
speed.
D
Lubricating oil
contamination in a gas turbine bearing oil sump will most likely come from
which of the following?
Failure of the
lube oil pump.
Fuel oil contamination.
Failure of the
scavenging pump.
Failure of seal
pressurization air.
C
The buildup of
contamination in a gas turbine will cause all of the following conditions
EXCEPT which of the following?
Increased combustion
gas temperatures
Restricted airflow
Reduced fuel consumption
Turbine blade
corrosion
A
Why is safety-wiring,
or lock wiring of gas turbine parts required?
Prevent disengagement
of parts.
Prevent corrosion.
Maintain lubrication.
Maintain fastener
torque.
B
On a gas turbine
powered vessel, what is the last step after an off-line water wash?
Open the Variable
Stator vanes.
Start the engine
to dry it out.
Release the gas
generator brake.
Secure the starting
system.
A
The effectiveness
of an off-line water wash of a GE LM gas turbine engine can be enhanced
by doing which of the following?
Stroking the Variable
Stator Vanes to the maximum open position.
Washing the power
turbine while still hot.
Motoring the engine
just short of idle speed.
Applying the power
turbine brake.
A
On a gas turbine
propulsion vessel, you notice a slow but steady increase in gas turbine
vibration and specific fuel consumption as the voyage has progressed. What
would be a good maintenance technique to use to correct these increases?
Secure the engine
and water wash the compressor off-line.
Increase the Variable
Stator Vane setting to supply more air to the combustor.
Water wash the
power turbine on-line.
Increase gas generator
RPM to a more efficient setting.
C
How do you gain
access to the burner units of a can-annular combustor to perform maintenance?
By removing the
annular case
By removing the
power turbine
By sliding the
can-annular case aside
By disassembling
the engine
D
What are the two
prime sources of deposits that build up on compressor blades?
Carbon residue
and lube oil mist
Salt spray and
carbon residue
Lube oil mist
and fuel oil spray
Lube oil mist
and salt spray
B
What is the power
source for the ignition exciter of a gas turbine engine?
Ship's 400 Hz
system.
Ship's 115 volt
AC system.
Ship's 28 volt
DC system.
Four lead-acid
batteries.
B
On the ignition
system of a gas turbine engine, how is optimum spark achieved?
Concentration
of minimum energy in maximum time.
Concentration
of maximum energy in minimum time.
Concentration
of maximum energy in maximum time.
Concentration
of minimum energy in minimum time.
B
What is the most
common type of spark igniter used on a gas turbine engine?
Resistive gap
Annular gap
Delayed gap
Suppression gap
B
On the marine
gas turbine engine panel shown in the illustration, which of the following
conditions would prevent the auto-start sequence from successfully completing?
Illustration GT-
Propeller pitch
at zero
Bleed air valve
open
Fuel supply cutoff
valve opened.
Starting motor
not turning.
C
Power is defined
as which of the following?
Force applied
through a distance.
The rate of applying
a force.
The rate of doing
work.
Work performed
through a distance.
D
Potential energy
is defined as which of the following?
The energy a body
possesses due to its motion.
A measurement
in feet per second.
A total pressure
measurement.
The energy a body
possesses due to its position.
C
Which of the following
terms refers to thermal energy in transition?
Power
Foot-Pound
Heat
Horsepower
D
What is the term
given to a process that occurs without a loss or gain of heat?
Exothermic.
Isothermal
Endothermic.
Adiabatic
B
Rankine is the
temperature scale that corresponds to which of the following?
Absolute reading
of a measured temperature in degrees Kelvin.
Absolute reading
of a measured temperature in degrees Fahrenheit.
Absolute reading
of a measured temperature in degrees Fahrenheit + 273.
Absolute reading
of a measured temperature in degrees Celsius.
A
Kelvin is the
absolute temperature scale that corresponds to which of the following?
Absolute reading
of a measured temperature in degrees Celsius.
Absolute reading
of a measured temperature in degrees Fahrenheit.
Absolute reading
of a measured temperature in degrees Rankine.
None of the above.
D
Which of the following
is the definition of absolute temperature?
Temperature measured
with reference to 0 degrees Fahrenheit.
Temperature measured
with reference to 0 degrees Celsius.
Temperature measured
with reference to 273 degrees Rankine.
Temperature measured
with reference to the theoretical temperature at which all molecular motion
stops.
D
Thermal energy
is the only form of energy that can be added to or removed from a substance.
How is thermal energy that is added to a substance stored?
In the form of
potential kinetic energy.
In the form of
heat.
In the form of
mechanical energy.
In the form of
internal energy.
D
"Standard
Day" conditions, as defined by the ISO, is which of the following?
29.92 in HG @
15 deg C.
14.69 psi @ 59
deg F.
14.69 in HG @
59 deg C.
Both A and B.
D
Under standard
atmospheric conditions, 208.7 PSIG converts to approximately what in absolute
pressure?
104.7 PSIA
214.7 PSIA
194.0 PSIA
223.4 PSIA.
B
A temperature
of 69.5 degrees Fahrenheit converts to approximately what temperature in
degrees Rankine?
342.5 degrees
R.
529.5 degrees
R.
590.5 degrees R.
203.5 degrees
R.
A
A temperature
of 32.5 degrees Celsius converts to approximately what temperature in degrees
Kelvin?
305.5 degrees
K.
240.5 degrees
K.
492.5 degrees
K.
427.5 degrees
K.
A
Newton's Second
Law of Motion states which of the following?
An unbalancing
force on a body tends to produce an acceleration in the same direction of
the force applied.
The acceleration
of a body is inversely proportional to the applied force.
An unbalancing
force on a body tends to produce an acceleration in the opposite direction
of the force applied.
The acceleration
of a body is directly proportional to the mass.
B
Newton's Third
Law of Motion states which of the following?
For every acting
force there is an unequal and opposite reacting force.
For every acting
force there is an equal and opposite reacting force.
For every acting
force there is an equal reacting force in the opposite direction.
For every acting
force there is no reacting force in the up or down directions.
A
Newton's First
Law of Motion states which of the following?
A body in a state
of rest tends to remain at rest, and a body in motion continues to stay
in motion at a constant speed, unless acted upon by some external force.
A body at rest
will remain at rest when an external force is applied.
A body in motion
will continue to stay in motion, when an equal and opposite external force
is applied.
A body in a state
of rest tends to remain at rest, and a body in motion continues to stay
in motion, when an external force is applied.
A
Which of the following
statements concerning fluid flow is true?
If a fluid flowing
through a tube reaches a constriction or narrowing of the tube, the velocity
of the fluid flowing through the restriction increases and the pressure
decreases.
If a fluid flowing
through a tube reaches a constriction or narrowing of the tube, the velocity
of the fluid flowing through the restriction decreases and the pressure
decreases.
If a fluid flowing
through a tube reaches a constriction or narrowing of the tube, the velocity
of the fluid flowing through the restriction decreases and the pressure
increases.
If a fluid flowing
through a tube reaches a constriction or narrowing of the tube, the velocity
of the fluid flowing through the restriction increases and the pressure
increases.
B
The term "divergent"
is best described as which of the following?
Maintaining an
equal distance between edges.
Moving away from
each other, as the inner walls of a tube that flare outward.
Approaching nearer
together, as the inner walls of a tube that is constricted.
Thermal and kinetic
energy being converted to mechanical energy.
D
Provisions for
avoiding the buildup of ice on the intake air surfaces of a gas turbine
plant can be found where?
In the inlet duct
frame at the inlet to the engine.
In the exhaust
and intake ducting.
In the stack intake
ducting.
Both A & B.
D
The two basic
types of compressors used in gas turbine engines are which of the following?
Centrifugal and
reciprocating.
Axial and lobe.
Axial and reciprocating.
Centrifugal and
axial.
C
In comparing a
centrifugal-type to an axial-type compressor, which of the following statements
is true?
Centrifugal compressors
are more expensive to manufacture than a axial compressor.
Centrifugal compressors
have a lower compression ratio per stage than a axial compressor.
Centrifugal compressors
have a higher compression ratio per stage than an axial flow compressor.
A centrifugal
compressor has a lower resistance to FOD than a axial compressor.
D
What is the disadvantage
of a dual-entry centrifugal compressor compared to a single-entry centrifugal
compressor?
The dual-entry
compressor has a greater efficiency.
The dual-entry
compressor rotates at slower speeds.
The dual-entry
compressor is larger in diameter.
The dual-entry
compressor utilizes a more complicated inlet ducting.
D
A centrifugal
compressor assembly consists of which of the following?
A stationary impeller
and a rotating diffuser.
Stationary vanes
and rotating blades
Rotating pistons
and stationary liners.
A rotating impeller
and a stationary diffuser.
C
Which of the following
statements is true regarding centrifugal compressors?
The impeller of
a centrifugal compressor has a radial inlet and axial discharge.
The efficiency
of a centrifugal compressor is greater than that of an axial compressor.
The centrifugal
compressor is frequently used on small, low power turbines.
Centrifugal compressors
are complicated in design and heavy.
C
While air is being
compressed in a centrifugal flow gas turbine, what happens to the direction
of air flow?
Changes only once
from inlet to outlet.
Changes only at
the compressor inlet.
Changes at each
separate component.
Changes only at
the compressor discharge.
B
In a centrifugal
compressor, which component reduces the velocity and increases the static
pressure of the air?
Impeller
Diffuser
Eductor
Volute
B
Before combustion
can occur, the combustion air must be delivered to the combustor at a high-pressure
and low-velocity. High-velocity, low-pressure air is converted to high-pressure,
low-velocity air at what part of a centrifugal-type compressor?
Inlet plenum.
Diffuser.
Turning vanes.
Impeller.
A
A pressure stage
of an axial-type compressor consists of which of the following?
Set of rotor blades
and a set of stator blades.
Compressor rotor
and a set of inlet guide vanes.
Set of stator
blades.
Set of rotor blades.
C
An axial compressor
basically consists of which of the following?
A rotating impeller
and a stationary diffuser.
Rotating pistons
and stationary liners.
Stationary vanes
and rotating blades.
A stationary impeller
and a rotating diffuser.
B
The purpose of
the metal spray rub coating on the rotor and stator casing of an axial type
compressor is which of the following?
control airflow
through the compressor
provide close
vane to rotor and blade to stator case clearances
seal the circumferential
dovetails
ensure protection
for the gearbox adapter when removing or replacing the bearings
A
Each stage of
an axial-compressor of a gas turbine can compress the atmospheric air a
total of how many times?
1.2 times
2.2 times
3.2 times
4.2 times
A
An axial compressor
stage is represented by which of the following components and in which order?
One set of rotating
blades, one set of stationary vanes.
One set of stationary
vanes, one set of rotating blades.
One set of rotating
blades, two sets of stationary vanes.
One set of rotating
vanes, one set of stationary blades.
D
Which of the following
is the main advantage of a split axial compressor case?
Simpler to disassemble.
Stronger construction.
Cheaper to manufacture.
Easier to repair
and inspect.
C
What is the term
used to describe the stationary vanes preceding the first stage of an axial
compressor?
Variable stator
vanes.
Variable inlet
vanes.
Inlet guide vanes.
First stage stator
vanes.
B
What is the function
of the stator in a axial gas turbine compressor?
To convert pressure
to velocity.
To convert velocity
to pressure.
To increase volume.
To provide velocity
energy.
C
An axial compressor
stator vane that is mechanically adjusted to provide optimum compressor
performance over a wide operating range is referred to as which of the following?
Variable Guide
Vane (VGV)
Static Guide Vane
(SGV)
Variable Stator
Vane (VSV)
Inlet Guide Vane
(IGV)
C
Variable stator
vanes give an axial gas turbine compressor which of the following capabilities?
Increases pressure
ratios.
Increased primary
air flow.
Efficiency at
various speeds.
Ability to operate
at constant speeds.
A
Two functions
of the compressor stator vanes include which of the following?
Direct air flow
to each rotor stage at the correct angle and deliver air to the combustor
at the correct velocity and pressure.
Direct air flow
to rotor blades at the correct angle and are shaped to produce a velocity
increase and maintain a constant pressure.
Direct air flow
to rotor blades at the correct angle and are shaped to cause a velocity
increase and a pressure decrease.
Direct air flow
to rotor blades at the correct angle and are shaped to maintain a constant
velocity and produce a pressure increase.
B
The primary function
of an axial compressor rotor blade is which of the following?
To use centrifugal
force to increase the pressure of the air stream.
To impart acceleration
to the air mass, resulting in an increase in velocity.
To act as a diffuser
to the air flow causing an increase in pressure with a resultant decrease
in velocity.
To change the
direction of the air flow.
D
What are the two
common forms of axial compressor rotor blade roots?
Grub and bulb.
Fir tree and key.
Sawtooth and knob.
Fir tree and bulb.
D
What is a compressor
midspan shrould?
A support for
the tips of stator blades.
The center of
a two-piece rotor blade.
A way of securing
stator blades.
A brace built
into the middle of a rotor blade for damping.
B
Why are loose-fitting
blades used on the first several stages of large axial compressors?
To compensate
for a malfunctioning compressor support bearing.
To minimize vibration
while the engine is passing through critical speed ranges.
To compensate
for the abrasive action of the blade tips.
To maintain close
tolerances in the compressor.
C
Which of the following
statements is true about an axial compressor disk-type rotor?
Rotor is only
suitable for low-speed compressors.
Rotor discs are
held together by through bolts.
Rotor disks are
shrunk fit onto a steel shaft.
Rotor consists
of rings that are flanged to fit one against the other.
A
In a gas turbine
engine, the majority of the energy is added to the working fluid in which
of the following components?
Combustor.
Power Turbine.
Compressor.
High Pressure
Turbine.
A
The three most
common types of combustors used in gas turbine engines are which of the
following?
Can, Annular,
and Can-Annular.
Can, Derivative,
and Can-Derivative.
Can, Vortex, and
Can-Vortex.
Can, Angular,
and Can-Angular.
B
A centrifugal-flow
gas turbine uses what type of combustion chamber?
Double-Annular
Can
Can-Annular
Annular
D
The short length
of the can-annular combustion chamber provides for which of the following
conditions?
Maximum pressure
drop of the gases between the compressor outlet and the flame area.
Decreased combustor
temperature.
Increased combustor
temperature.
Minimal pressure
drop of the gases between the compressor outlet and the flame area.
C
When dissimilar
metals come in contact with a conductor, which of the following types of
metal deterioration takes place?
Rust erosion.
Chemical corrosion.
Electrochemical
corrosion.
Etching erosion.
B
A reddish-colored
oxide usually forms on which of the following metals?
Aluminum.
Steel.
Chromium.
Magnesium.
D
A white-gray powdery
deposit can usually found on which of the following metals?
Steel.
Magnesium.
Magnetite.
Aluminum.
C
Active corrosion
on copper alloys is indicated by which of the following?
A white-gray powder
formation.
A copper-oxide
crust formation.
A gray-green patina
formation.
A verdigris formation.
D
Cadmium and zinc
coatings provide which of the following type of protection for the base
metal?
Sealant.
Chemical.
Thermal.
Sacrificial.
C
Which of the following
conditions will NOT be the result of a build-up of deposits in a gas turbine
compressor?
Increased combustion
gas temperatures.
Restricted air
flow.
Reduced fuel consumption.
Turbine blade
corrosion.
A
Compressor tip
clang can be usually attributed to which of the following operating conditions?
Compressor stall.
Overloading.
Continuous high-power
operation.
Continuous low-power
operation.
D
Compressor rotor
blade tip curl is usually caused by which of the following?
Misalignment.
Object damage.
Vane rub.
Blade rub.
D
Once a compressor
is broken in, which of the following factors will most likely cause blade
tips to rub?
Sprayed material
in the stator case
Elongation of
the blade tips
Profiles on the
blade tips
Failure of a rotor
bearing
B
What type of metallurgical
failure does Item A represent in the illustration? Illustration GT-
Rupture.
Radial cracking.
Creep.
Axial cracking.
B
What type of metallurgical
failure does Item B represent in the illustration? Illustration GT-
Circumferential
cracking.
Axial cracking.
Weld cracking.
Radial cracking.
A
You are conducting
a borescope inspection of the compressor section of a GE LM gas turbine.
In stage four, you see a slight tilt to one blade and the blade platform
is raised higher than the other blades. What could be a cause of this condition
and what would be your course of action?
Condition could
be the result of blade root failure. Engine should be taken out of service
until condition can be evaluated.
FOD damage could
cause this condition. Engine can be operated at full load until next scheduled
maintenance.
Metal fatigue
could cause this condition. Engine can be operated but gas generator speed
should be reduced.
Ice damage could
cause this condition. Blade tilt should be corrected using special tool
provided, then engine will be safe to operate.
A
A compressor blade
platform that is tilted or raised may indicate which of the following failures?
Blade root.
Carboloy pad.
Midspan damper.
Tip clang.
C
When tip clang
takes place on a gas turbine engine, the major damage occurs to what area
of the blade?
Chord
Tip
Root
Midspan
A
You are conducting
a borescope inspection of the combustor section of a GE LM gas turbine
engine. You observe a one square inch hole in the combustor dome where burn
through has removed the metal. What would be your course of action?
Record the damage
and continue to operate the engine while monitoring the high pressure turbine
temperatures and nozzle condition.
Immediately take
the engine out of service.
Operate the engine
only in an emergency and at reduced load.
Make temporary
repairs with on board repair kit to patch hole.
C
The dimples of
a combustor dome band that has a low operating time will usually have what
kind of damage?
Burn away.
Bowing.
Cracks.
Burn through.
Questions for Hayward Bearing, Main Turbine (set of 2) (axv055p)
The wheel bearings have gone bad if you ever see small ball bearings in your pool, pump basket or filter. The cleaner will stop moving if the turbine bearings fall apart.
Reply
Goto Hangzhou Journal Bearing to know more.
Hello Barb - These turbine bearings will work in the Hayward Aquadroid, Elite, Aquabug, Pool Vac Classic, Pool Vac, Navigator, Pool Vac Ultra, Diver Dave, Wanda Wha;e, Navigator Pro, and Pool Vac XL. If your cleaner is not listed, these are not the correct bearings.
Reply
Are you interested in learning more about Gas Turbine Bearing? Contact us today to secure an expert consultation!
Hi Peter, The turbine bearings can not be used for the A-Frame and the A-Frame bearings are not sold separately. You will have to replace the entire A-Frame Kit (AXV621D).
Reply
Hi David, No clips do not come with these bearings. Could you send us a few photos? To supply photos simply click the reply link below and upload your photos. Once we get those photos we can make the proper recommendation.
Reply
If you want to learn more, please visit our website Thrust Pad Bearing.
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