4670812
Descrição
Quiz por TRAVIS CANNING, atualizado more than 1 year ago
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Criado por TRAVIS CANNING
mais de 8 anos atrás
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Questão 1
Questão
In a large steam turbine lubricating oil system the function of the oil is to lubricate and ___________ the bearings.
Responda
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keep dirt out of
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polish
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cool
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keep moisture away from
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support
Questão 2
Questão
what type of instrumentation ins installed on the discharge side of an oil lubricated bearing
Responda
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oil filter
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moisture separator
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dewpoint monitor
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flow measuring device
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thermometer
Questão 3
Questão
When a turbine is left cold and at a standstill, the weight of the rotor will tend to cause the rotor to sag slightly, this is also referred to as
Responda
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bowing
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hogging
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sagging
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warping
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bending
Questão 4
Questão
when a hot turbine rotor has cooled at a standstill, the lower half will cool faster than the upper half. This may cause the rotor to bend upwards which may also be referred to as:
Responda
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bowing
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hogging
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sagging
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warping
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bending
Questão 5
Questão
when a steam turbine is shut down it should be put on barring gear for a minimum of:
Responda
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3 hours
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24 hours
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72 hours
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as determined by the plant manager
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barring should never be shut off
Questão 6
Questão
Barring gear shaft rotation is typically:
Responda
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1-3 rpm
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5-10 rpm
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20-40 rpm
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60 rpm
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3600 rpm
Questão 7
Questão
while large steam turbine is on barring gear what other system should be placed in service
Responda
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lube oil coolers
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lube oil filtering
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hydrogen sealing
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stator water
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jacking oil
Questão 8
Questão
which of the following is not a type of steam turbine governing:
Responda
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Nozzle
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Throttle
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Overload
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Bypass
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Impulse
Questão 9
Questão
Nozzle governing is utilized on __________ turbines
Responda
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impulse
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reaction
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condensing
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extraction
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impulse or reaction turbines
Questão 10
Questão
Nozzle governing
Responda
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opens a nozzle from 0 % to 100 % as the load is increased on a turbine
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opens a series of nozzles in succession as the load is increased
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utilizes flyball weights to control a steam valve
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is used on the later stages of an impulse turbine to control speed
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none of the above
Questão 11
Questão
Impulse steam turbine speed can be controlled by throttling the steam supply through a control valve and:
Responda
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varying the firing rate on the boiler
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increasing the load on the generator
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increasing the superheat to the steam
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opening or closing a series of nozzles
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bypassing the low pressure turbine through extraction
Questão 12
Questão
Bypass governing allows
Responda
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an increase in load but a decreased efficiency
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an increase in load with a increase in efficiency
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a decrease in load with a decrease in efficiency
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a decrease in load with an increase in efficiency
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increase load with no change in efficiency
Questão 13
Questão
The difference between the no-load and full-load speed, expressed as a percentage of the set speed, is called the ______ of the governor. As the load increases, the speed will ________ below the set speed.
Responda
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lag
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droop
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variance
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offset
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drag
Questão 14
Questão
In a simple flyweight governor:
Responda
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speed is controlled by varying the number of weights in the governor
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speed is controlled by restricting the inward movement
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the weights move inward with an increase in speed
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increasing spring tension increases the controlled spring
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all of the above
Questão 15
Questão
When a steam turbine exceeds its speed setpoint
Responda
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boiler pressure is reduced to limit the steam speed
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the flyball weights will move outward which will in turn operate an oil relay which will close off the steam valve
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the turbine will likely catastrophically fail
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the barring gear will engage and act as a clutch to reduce the speed
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a braking system is employed until within limits
Questão 16
Questão
Turbine lubricating oil
Responda
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Is not required for small impulse turbines
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must be changed every four months
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lubricates the blades
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can be used to operate the turbine governor
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should be preheated before use
Questão 17
Questão
The turbine overspeed trip:
1. prevents the turbine from vibrating
2. prevents the turbine exceeding the maximum rated speed
3. is operated by a spring loaded pin in the rotating blades
4. will close the steam stop valve
5. should be tested before the turbine is placed in service
Responda
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2,4,5
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2,3,4,5
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1,2,4
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3,4,5
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4,5
Questão 18
Questão
The overspeed trip of a steam turbine
Responda
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operates on turbine vibrations due to high speed
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is installed on all turbines
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can be adjusted according to the load demand
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is regulated by exhaust pressure
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sheds the load in the event of high pressure
Questão 19
Questão
Turbine overspeed trip
Responda
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prevents the turbine from vibrating
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will close the steam stop valve to the turbine
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is operated by a spring loaded pin in the rotating blades
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supplies the operator with rpm indications
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reduces the turbine speed by increasing the back pressure
Questão 20
Questão
The great majority of steam turbine governing systems utilize
Responda
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hydraulic system principle
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pneumatic system principle
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mechanical centrifugal principle
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lever principle
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bimetal expansion principle
Questão 21
Questão
when starting a steam turbine it is customary practice to:
Responda
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analyze the oil for water prior to rolling
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turn on all cooling water systems first
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place the speed control system in service once the unit is rolling
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test the overspeed trip as soon as running speed is attained
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stop the auxiliary oil pump as soon as steam begins to turn the unit
Questão 22
Questão
which of the following mechanisms would not be sued on an emergency overspeed trip device?
Responda
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pneumatic
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electrical
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hydraulic
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mechanical
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any of the above may be used
Questão 23
Questão
when starting up a cold steam turbine, what position should the main steam valve intitially be opened to?
Responda
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10 % or less
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25 %
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50 %
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75 %
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100 %
Questão 24
Questão
when is the barring gear engaged on a large turbine during a shutdown
Responda
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when the main steam stop valve is closed
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at 50 % operating speed
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when the turbine is rotating at 3rpm or less
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upon opening the generator breaker
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when the turbine has come to a complete stop
Questão 25
Questão
On shutting down a large steam turbine what is one of the first steps that an operator should do once the main steam valve is closed?
Responda
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shut off the boiler feed pump
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drain the boiler
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open the turbine drains
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put your feet up and have an extended coffee break
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hang the boiler lock-out tags
Questão 26
Questão
During the operation of a large steam turbine:
Responda
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the main auxiliary oil pump supplies oil to the journal bearings
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the main auxiliary oil pump is driven by the turbine shaft
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if the main oil pump fails the jacking oil pump may take over
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the emergency overspeed trip receives the same oil pressure as the journal bearings
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only answers A) and B) from above
Questão 27
Questão
When a turbine hydraulic overspeed trip is activated
1. a spring closes the main steam valve
2. oil pressure quickly closes the main steam valve
3. the oil pilot drain closes
4. oil pressure to the valve is shut off
5. the stop valve oil cylinder drain is opened
Responda
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1,2,3,4,5
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1,4,5
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2,4
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1,3,5
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none of the above
Questão 28
Questão
Which of the following parameters are monitored and recorded during the operation on a steam turbine.
1. main steam pressure
2. main steam temperature
3. oil pressure and temperature
4. condenser vacuum
5. hotwell pressure and temperature
Responda
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1,2,3,4
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2,3,4,5
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1,3,4,5
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1,2,4,5
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all of the above
Questão 29
Questão
The internal spring loaded tripping bold has a center of gravity:
Responda
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at midpoint
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towards the head end of the bold
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towards the nut end of the bolt
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concentric
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perpendicular with the shaft
Questão 30
Questão
The overspeed trip on a steam turbine is typically set to operate at ______________ % overspeed
Responda
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5%
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10%
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20%
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25%
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50%
Questão 31
Questão
The purpose of a condenser is to:
Responda
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extract heat from the condensate to be returned back to the cooling pond
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subcool the condensate below the saturation temperature
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convert the steam to water after the steam has expanded through the turbine
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remove the non-condensables from the steam
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improve the boiler overall efficiency
Questão 32
Questão
The addition of a condenser to a steam turbine vs a turbine exhausting to atmosphere may increase the overall efficiency of the turbine by:
Responda
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10%
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25%
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50%
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75%
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100%
Questão 33
Questão
A surface condenser: (pick the incorrect answer)
Responda
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acts as a dearator
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converts steam to condensate
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helps maintain vacuum at the turbine exhaust
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cools the condensate below the saturation temperature
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may be cylindrical, oval or rectangular in shape
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