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power engineering 3b2 Test sobre power prep Steam turbine Auxiliaries and Operation quiz, creado por TRAVIS CANNING el 27/02/2016.

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power prep Steam turbine Auxiliaries and Operation quiz

Pregunta 1 de 33

1

In a large steam turbine lubricating oil system the function of the oil is to lubricate and ___________ the bearings.

Selecciona una de las siguientes respuestas posibles:

  • keep dirt out of

  • polish

  • cool

  • keep moisture away from

  • support

Explicación

Pregunta 2 de 33

1

what type of instrumentation ins installed on the discharge side of an oil lubricated bearing

Selecciona una de las siguientes respuestas posibles:

  • oil filter

  • moisture separator

  • dewpoint monitor

  • flow measuring device

  • thermometer

Explicación

Pregunta 3 de 33

1

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

Selecciona una de las siguientes respuestas posibles:

  • bowing

  • hogging

  • sagging

  • warping

  • bending

Explicación

Pregunta 4 de 33

1

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:

Selecciona una de las siguientes respuestas posibles:

  • bowing

  • hogging

  • sagging

  • warping

  • bending

Explicación

Pregunta 5 de 33

1

when a steam turbine is shut down it should be put on barring gear for a minimum of:

Selecciona una de las siguientes respuestas posibles:

  • 3 hours

  • 24 hours

  • 72 hours

  • as determined by the plant manager

  • barring should never be shut off

Explicación

Pregunta 6 de 33

1

Barring gear shaft rotation is typically:

Selecciona una de las siguientes respuestas posibles:

  • 1-3 rpm

  • 5-10 rpm

  • 20-40 rpm

  • 60 rpm

  • 3600 rpm

Explicación

Pregunta 7 de 33

1

while large steam turbine is on barring gear what other system should be placed in service

Selecciona una de las siguientes respuestas posibles:

  • lube oil coolers

  • lube oil filtering

  • hydrogen sealing

  • stator water

  • jacking oil

Explicación

Pregunta 8 de 33

1

which of the following is not a type of steam turbine governing:

Selecciona una de las siguientes respuestas posibles:

  • Nozzle

  • Throttle

  • Overload

  • Bypass

  • Impulse

Explicación

Pregunta 9 de 33

1

Nozzle governing is utilized on __________ turbines

Selecciona una de las siguientes respuestas posibles:

  • impulse

  • reaction

  • condensing

  • extraction

  • impulse or reaction turbines

Explicación

Pregunta 10 de 33

1

Nozzle governing

Selecciona una de las siguientes respuestas posibles:

  • opens a nozzle from 0 % to 100 % as the load is increased on a turbine

  • opens a series of nozzles in succession as the load is increased

  • utilizes flyball weights to control a steam valve

  • is used on the later stages of an impulse turbine to control speed

  • none of the above

Explicación

Pregunta 11 de 33

1

Impulse steam turbine speed can be controlled by throttling the steam supply through a control valve and:

Selecciona una de las siguientes respuestas posibles:

  • varying the firing rate on the boiler

  • increasing the load on the generator

  • increasing the superheat to the steam

  • opening or closing a series of nozzles

  • bypassing the low pressure turbine through extraction

Explicación

Pregunta 12 de 33

1

Bypass governing allows

Selecciona una de las siguientes respuestas posibles:

  • an increase in load but a decreased efficiency

  • an increase in load with a increase in efficiency

  • a decrease in load with a decrease in efficiency

  • a decrease in load with an increase in efficiency

  • increase load with no change in efficiency

Explicación

Pregunta 13 de 33

1

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.

Selecciona una de las siguientes respuestas posibles:

  • lag

  • droop

  • variance

  • offset

  • drag

Explicación

Pregunta 14 de 33

1

In a simple flyweight governor:

Selecciona una de las siguientes respuestas posibles:

  • speed is controlled by varying the number of weights in the governor

  • speed is controlled by restricting the inward movement

  • the weights move inward with an increase in speed

  • increasing spring tension increases the controlled spring

  • all of the above

Explicación

Pregunta 15 de 33

1

When a steam turbine exceeds its speed setpoint

Selecciona una de las siguientes respuestas posibles:

  • boiler pressure is reduced to limit the steam speed

  • the flyball weights will move outward which will in turn operate an oil relay which will close off the steam valve

  • the turbine will likely catastrophically fail

  • the barring gear will engage and act as a clutch to reduce the speed

  • a braking system is employed until within limits

Explicación

Pregunta 16 de 33

1

Turbine lubricating oil

Selecciona una de las siguientes respuestas posibles:

  • Is not required for small impulse turbines

  • must be changed every four months

  • lubricates the blades

  • can be used to operate the turbine governor

  • should be preheated before use

Explicación

Pregunta 17 de 33

1

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

Selecciona una de las siguientes respuestas posibles:

  • 2,4,5

  • 2,3,4,5

  • 1,2,4

  • 3,4,5

  • 4,5

Explicación

Pregunta 18 de 33

1

The overspeed trip of a steam turbine

Selecciona una de las siguientes respuestas posibles:

  • operates on turbine vibrations due to high speed

  • is installed on all turbines

  • can be adjusted according to the load demand

  • is regulated by exhaust pressure

  • sheds the load in the event of high pressure

Explicación

Pregunta 19 de 33

1

Turbine overspeed trip

Selecciona una de las siguientes respuestas posibles:

  • prevents the turbine from vibrating

  • will close the steam stop valve to the turbine

  • is operated by a spring loaded pin in the rotating blades

  • supplies the operator with rpm indications

  • reduces the turbine speed by increasing the back pressure

Explicación

Pregunta 20 de 33

1

The great majority of steam turbine governing systems utilize

Selecciona una de las siguientes respuestas posibles:

  • hydraulic system principle

  • pneumatic system principle

  • mechanical centrifugal principle

  • lever principle

  • bimetal expansion principle

Explicación

Pregunta 21 de 33

1

when starting a steam turbine it is customary practice to:

Selecciona una de las siguientes respuestas posibles:

  • analyze the oil for water prior to rolling

  • turn on all cooling water systems first

  • place the speed control system in service once the unit is rolling

  • test the overspeed trip as soon as running speed is attained

  • stop the auxiliary oil pump as soon as steam begins to turn the unit

Explicación

Pregunta 22 de 33

1

which of the following mechanisms would not be sued on an emergency overspeed trip device?

Selecciona una de las siguientes respuestas posibles:

  • pneumatic

  • electrical

  • hydraulic

  • mechanical

  • any of the above may be used

Explicación

Pregunta 23 de 33

1

when starting up a cold steam turbine, what position should the main steam valve intitially be opened to?

Selecciona una de las siguientes respuestas posibles:

  • 10 % or less

  • 25 %

  • 50 %

  • 75 %

  • 100 %

Explicación

Pregunta 24 de 33

1

when is the barring gear engaged on a large turbine during a shutdown

Selecciona una de las siguientes respuestas posibles:

  • when the main steam stop valve is closed

  • at 50 % operating speed

  • when the turbine is rotating at 3rpm or less

  • upon opening the generator breaker

  • when the turbine has come to a complete stop

Explicación

Pregunta 25 de 33

1

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?

Selecciona una de las siguientes respuestas posibles:

  • shut off the boiler feed pump

  • drain the boiler

  • open the turbine drains

  • put your feet up and have an extended coffee break

  • hang the boiler lock-out tags

Explicación

Pregunta 26 de 33

1

During the operation of a large steam turbine:

Selecciona una de las siguientes respuestas posibles:

  • the main auxiliary oil pump supplies oil to the journal bearings

  • the main auxiliary oil pump is driven by the turbine shaft

  • if the main oil pump fails the jacking oil pump may take over

  • the emergency overspeed trip receives the same oil pressure as the journal bearings

  • only answers A) and B) from above

Explicación

Pregunta 27 de 33

1

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

Selecciona una de las siguientes respuestas posibles:

  • 1,2,3,4,5

  • 1,4,5

  • 2,4

  • 1,3,5

  • none of the above

Explicación

Pregunta 28 de 33

1

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

Selecciona una de las siguientes respuestas posibles:

  • 1,2,3,4

  • 2,3,4,5

  • 1,3,4,5

  • 1,2,4,5

  • all of the above

Explicación

Pregunta 29 de 33

1

The internal spring loaded tripping bold has a center of gravity:

Selecciona una de las siguientes respuestas posibles:

  • at midpoint

  • towards the head end of the bold

  • towards the nut end of the bolt

  • concentric

  • perpendicular with the shaft

Explicación

Pregunta 30 de 33

1

The overspeed trip on a steam turbine is typically set to operate at ______________ % overspeed

Selecciona una de las siguientes respuestas posibles:

  • 5%

  • 10%

  • 20%

  • 25%

  • 50%

Explicación

Pregunta 31 de 33

1

The purpose of a condenser is to:

Selecciona una de las siguientes respuestas posibles:

  • extract heat from the condensate to be returned back to the cooling pond

  • subcool the condensate below the saturation temperature

  • convert the steam to water after the steam has expanded through the turbine

  • remove the non-condensables from the steam

  • improve the boiler overall efficiency

Explicación

Pregunta 32 de 33

1

The addition of a condenser to a steam turbine vs a turbine exhausting to atmosphere may increase the overall efficiency of the turbine by:

Selecciona una de las siguientes respuestas posibles:

  • 10%

  • 25%

  • 50%

  • 75%

  • 100%

Explicación

Pregunta 33 de 33

1

A surface condenser: (pick the incorrect answer)

Selecciona una de las siguientes respuestas posibles:

  • acts as a dearator

  • converts steam to condensate

  • helps maintain vacuum at the turbine exhaust

  • cools the condensate below the saturation temperature

  • may be cylindrical, oval or rectangular in shape

Explicación

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