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power prep Steam turbine Auxiliaries and Operation quiz
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Questions in this quiz (33)
1In a large steam turbine lubricating oil system the function of the oil is to lubricate and ___________ the bearings.
- Akeep dirt out of
- Bpolish
- Ccool
- Dkeep moisture away from
- Esupport
2what type of instrumentation ins installed on the discharge side of an oil lubricated bearing
- Aoil filter
- Bmoisture separator
- Cdewpoint monitor
- Dflow measuring device
- Ethermometer
3When 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
- Abowing
- Bhogging
- Csagging
- Dwarping
- Ebending
4when 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:
- Abowing
- Bhogging
- Csagging
- Dwarping
- Ebending
5when a steam turbine is shut down it should be put on barring gear for a minimum of:
- A3 hours
- B24 hours
- C72 hours
- Das determined by the plant manager
- Ebarring should never be shut off
6Barring gear shaft rotation is typically:
- A1-3 rpm
- B5-10 rpm
- C20-40 rpm
- D60 rpm
- E3600 rpm
7while large steam turbine is on barring gear what other system should be placed in service
- Alube oil coolers
- Blube oil filtering
- Chydrogen sealing
- Dstator water
- Ejacking oil
8which of the following is not a type of steam turbine governing:
- ANozzle
- BThrottle
- COverload
- DBypass
- EImpulse
9Nozzle governing is utilized on __________ turbines
- Aimpulse
- Breaction
- Ccondensing
- Dextraction
- Eimpulse or reaction turbines
10Nozzle governing
- Aopens a nozzle from 0 % to 100 % as the load is increased on a turbine
- Bopens a series of nozzles in succession as the load is increased
- Cutilizes flyball weights to control a steam valve
- Dis used on the later stages of an impulse turbine to control speed
- Enone of the above
11Impulse steam turbine speed can be controlled by throttling the steam supply through a control valve and:
- Avarying the firing rate on the boiler
- Bincreasing the load on the generator
- Cincreasing the superheat to the steam
- Dopening or closing a series of nozzles
- Ebypassing the low pressure turbine through extraction
12Bypass governing allows
- Aan increase in load but a decreased efficiency
- Ban increase in load with a increase in efficiency
- Ca decrease in load with a decrease in efficiency
- Da decrease in load with an increase in efficiency
- Eincrease load with no change in efficiency
13The 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.
- Alag
- Bdroop
- Cvariance
- Doffset
- Edrag
14In a simple flyweight governor:
- Aspeed is controlled by varying the number of weights in the governor
- Bspeed is controlled by restricting the inward movement
- Cthe weights move inward with an increase in speed
- Dincreasing spring tension increases the controlled spring
- Eall of the above
15When a steam turbine exceeds its speed setpoint
- Aboiler pressure is reduced to limit the steam speed
- Bthe flyball weights will move outward which will in turn operate an oil relay which will close off the steam valve
- Cthe turbine will likely catastrophically fail
- Dthe barring gear will engage and act as a clutch to reduce the speed
- Ea braking system is employed until within limits
16Turbine lubricating oil
- AIs not required for small impulse turbines
- Bmust be changed every four months
- Clubricates the blades
- Dcan be used to operate the turbine governor
- Eshould be preheated before use
17The 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- A2,4,5
- B2,3,4,5
- C1,2,4
- D3,4,5
- E4,5
18The overspeed trip of a steam turbine
- Aoperates on turbine vibrations due to high speed
- Bis installed on all turbines
- Ccan be adjusted according to the load demand
- Dis regulated by exhaust pressure
- Esheds the load in the event of high pressure
19Turbine overspeed trip
- Aprevents the turbine from vibrating
- Bwill close the steam stop valve to the turbine
- Cis operated by a spring loaded pin in the rotating blades
- Dsupplies the operator with rpm indications
- Ereduces the turbine speed by increasing the back pressure
20The great majority of steam turbine governing systems utilize
- Ahydraulic system principle
- Bpneumatic system principle
- Cmechanical centrifugal principle
- Dlever principle
- Ebimetal expansion principle
21when starting a steam turbine it is customary practice to:
- Aanalyze the oil for water prior to rolling
- Bturn on all cooling water systems first
- Cplace the speed control system in service once the unit is rolling
- Dtest the overspeed trip as soon as running speed is attained
- Estop the auxiliary oil pump as soon as steam begins to turn the unit
22which of the following mechanisms would not be sued on an emergency overspeed trip device?
- Apneumatic
- Belectrical
- Chydraulic
- Dmechanical
- Eany of the above may be used
23when starting up a cold steam turbine, what position should the main steam valve intitially be opened to?
- A10 % or less
- B25 %
- C50 %
- D75 %
- E100 %
24when is the barring gear engaged on a large turbine during a shutdown
- Awhen the main steam stop valve is closed
- Bat 50 % operating speed
- Cwhen the turbine is rotating at 3rpm or less
- Dupon opening the generator breaker
- Ewhen the turbine has come to a complete stop
25On 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?
- Ashut off the boiler feed pump
- Bdrain the boiler
- Copen the turbine drains
- Dput your feet up and have an extended coffee break
- Ehang the boiler lock-out tags
26During the operation of a large steam turbine:
- Athe main auxiliary oil pump supplies oil to the journal bearings
- Bthe main auxiliary oil pump is driven by the turbine shaft
- Cif the main oil pump fails the jacking oil pump may take over
- Dthe emergency overspeed trip receives the same oil pressure as the journal bearings
- Eonly answers A) and B) from above
27When 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- A1,2,3,4,5
- B1,4,5
- C2,4
- D1,3,5
- Enone of the above
28Which 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- A1,2,3,4
- B2,3,4,5
- C1,3,4,5
- D1,2,4,5
- Eall of the above
29The internal spring loaded tripping bold has a center of gravity:
- Aat midpoint
- Btowards the head end of the bold
- Ctowards the nut end of the bolt
- Dconcentric
- Eperpendicular with the shaft
30The overspeed trip on a steam turbine is typically set to operate at ______________ % overspeed
- A5%
- B10%
- C20%
- D25%
- E50%
31The purpose of a condenser is to:
- Aextract heat from the condensate to be returned back to the cooling pond
- Bsubcool the condensate below the saturation temperature
- Cconvert the steam to water after the steam has expanded through the turbine
- Dremove the non-condensables from the steam
- Eimprove the boiler overall efficiency
32The addition of a condenser to a steam turbine vs a turbine exhausting to atmosphere may increase the overall efficiency of the turbine by:
- A10%
- B25%
- C50%
- D75%
- E100%
33A surface condenser: (pick the incorrect answer)
- Aacts as a dearator
- Bconverts steam to condensate
- Chelps maintain vacuum at the turbine exhaust
- Dcools the condensate below the saturation temperature
- Emay be cylindrical, oval or rectangular in shape
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- power engineering 3b2 Quiz on power prep Steam turbine Auxiliaries and Operation quiz, created by TRAVIS CANNING on 27/02/2016.
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- TRAVIS CANNING
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- English
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