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power engineering 3b2 Quiz am power prep Steam turbine Auxiliaries and Operation quiz, erstellt von TRAVIS CANNING am 27/02/2016.

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TRAVIS CANNING
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power prep Steam turbine Auxiliaries and Operation quiz

power prep Steam turbine Auxiliaries and Operation quiz

Frage 1 von 33

1

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

Wähle eine der folgenden:

  • keep dirt out of

  • polish

  • cool

  • keep moisture away from

  • support

Erklärung

Frage 2 von 33

1

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

Wähle eine der folgenden:

  • oil filter

  • moisture separator

  • dewpoint monitor

  • flow measuring device

  • thermometer

Erklärung

Frage 3 von 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

Wähle eine der folgenden:

  • bowing

  • hogging

  • sagging

  • warping

  • bending

Erklärung

Frage 4 von 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:

Wähle eine der folgenden:

  • bowing

  • hogging

  • sagging

  • warping

  • bending

Erklärung

Frage 5 von 33

1

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

Wähle eine der folgenden:

  • 3 hours

  • 24 hours

  • 72 hours

  • as determined by the plant manager

  • barring should never be shut off

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Frage 6 von 33

1

Barring gear shaft rotation is typically:

Wähle eine der folgenden:

  • 1-3 rpm

  • 5-10 rpm

  • 20-40 rpm

  • 60 rpm

  • 3600 rpm

Erklärung

Frage 7 von 33

1

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

Wähle eine der folgenden:

  • lube oil coolers

  • lube oil filtering

  • hydrogen sealing

  • stator water

  • jacking oil

Erklärung

Frage 8 von 33

1

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

Wähle eine der folgenden:

  • Nozzle

  • Throttle

  • Overload

  • Bypass

  • Impulse

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Frage 9 von 33

1

Nozzle governing is utilized on __________ turbines

Wähle eine der folgenden:

  • impulse

  • reaction

  • condensing

  • extraction

  • impulse or reaction turbines

Erklärung

Frage 10 von 33

1

Nozzle governing

Wähle eine der folgenden:

  • 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

Erklärung

Frage 11 von 33

1

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

Wähle eine der folgenden:

  • 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

Erklärung

Frage 12 von 33

1

Bypass governing allows

Wähle eine der folgenden:

  • 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

Erklärung

Frage 13 von 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.

Wähle eine der folgenden:

  • lag

  • droop

  • variance

  • offset

  • drag

Erklärung

Frage 14 von 33

1

In a simple flyweight governor:

Wähle eine der folgenden:

  • 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

Erklärung

Frage 15 von 33

1

When a steam turbine exceeds its speed setpoint

Wähle eine der folgenden:

  • 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

Erklärung

Frage 16 von 33

1

Turbine lubricating oil

Wähle eine der folgenden:

  • 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

Erklärung

Frage 17 von 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

Wähle eine der folgenden:

  • 2,4,5

  • 2,3,4,5

  • 1,2,4

  • 3,4,5

  • 4,5

Erklärung

Frage 18 von 33

1

The overspeed trip of a steam turbine

Wähle eine der folgenden:

  • 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

Erklärung

Frage 19 von 33

1

Turbine overspeed trip

Wähle eine der folgenden:

  • 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

Erklärung

Frage 20 von 33

1

The great majority of steam turbine governing systems utilize

Wähle eine der folgenden:

  • hydraulic system principle

  • pneumatic system principle

  • mechanical centrifugal principle

  • lever principle

  • bimetal expansion principle

Erklärung

Frage 21 von 33

1

when starting a steam turbine it is customary practice to:

Wähle eine der folgenden:

  • 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

Erklärung

Frage 22 von 33

1

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

Wähle eine der folgenden:

  • pneumatic

  • electrical

  • hydraulic

  • mechanical

  • any of the above may be used

Erklärung

Frage 23 von 33

1

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

Wähle eine der folgenden:

  • 10 % or less

  • 25 %

  • 50 %

  • 75 %

  • 100 %

Erklärung

Frage 24 von 33

1

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

Wähle eine der folgenden:

  • 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

Erklärung

Frage 25 von 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?

Wähle eine der folgenden:

  • 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

Erklärung

Frage 26 von 33

1

During the operation of a large steam turbine:

Wähle eine der folgenden:

  • 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

Erklärung

Frage 27 von 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

Wähle eine der folgenden:

  • 1,2,3,4,5

  • 1,4,5

  • 2,4

  • 1,3,5

  • none of the above

Erklärung

Frage 28 von 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

Wähle eine der folgenden:

  • 1,2,3,4

  • 2,3,4,5

  • 1,3,4,5

  • 1,2,4,5

  • all of the above

Erklärung

Frage 29 von 33

1

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

Wähle eine der folgenden:

  • at midpoint

  • towards the head end of the bold

  • towards the nut end of the bolt

  • concentric

  • perpendicular with the shaft

Erklärung

Frage 30 von 33

1

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

Wähle eine der folgenden:

  • 5%

  • 10%

  • 20%

  • 25%

  • 50%

Erklärung

Frage 31 von 33

1

The purpose of a condenser is to:

Wähle eine der folgenden:

  • 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

Erklärung

Frage 32 von 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:

Wähle eine der folgenden:

  • 10%

  • 25%

  • 50%

  • 75%

  • 100%

Erklärung

Frage 33 von 33

1

A surface condenser: (pick the incorrect answer)

Wähle eine der folgenden:

  • 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

Erklärung

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