4th Class Power Engineering Part B 1&2 UPDATED ACTUAL Questions
and CORRECT Answers
Question: should be tested before the turbine is placed in service a) 2, 4, 5 b) 2, 3, 4, 5 c) 1, 2, 4 d) 3, 4, 5 e)
4, 5 b The over speed trip of a steam turbine a) operates on turbine vibrations due to high speed b) is
installed on all turbines c) can be adjusted according to the load demand d) is regulated by exhaust pressure
e) sheds the load in the event of high pressure b Turbine over speed trip a) prevents the turbine from
vibrating b) will close the steam stop valve to the turbine c) is operated by a spring loaded pin in the rotating
blades d) supplies the operator with rpm indications e) reduces the turbine speed by increasing the back
pressure d Turbine lubricating oil a) is not required for small impulse turbines b) must be changed every
four months c) lubricates the blades d) can be used to operate the turbine governor e) should be preheated
before use c The purpose of turbine glands is to prevent a) water from entering the turbine b) steam from
entering the turbine c) steam escaping from the turbine d) steam from entering the lubrication system e) oil
from entering the turbine e Shaft sealing in high output turbines is done with a) water seals b) mechanical
seals c) wear rings d) packing glands e) labyrinth seals b When the steam pressure drop occurs only the
stationary members or components of a turbine, the turbine is known as a) a single stage unit b) an impulse
unit c) a reaction unit d) a Parsons unit e) a cross compound reaction unit e A large reaction turbine will
have a) no thrust bearings b) steam pressure dropping in only the moving sections c) blades which are
basically symmetrical in cross-section d) never more than 5 stages e) steam pressure dropping through
moving and stationary sections e Turbine speed can be "fine tuned" with a device which will be limited to
about 10% over the rated speed. This device is the a) governor valve b) over speed governor c) sentinel
valve d) hand speed control e) over speed trip c Turbine thrust bearings are fixed to the casing and prevent
axial movement of the spindle by contacting a component on the shaft known as a a) shaft sleeve b)
labyrinth c) collar d) shroud e) diaphragm d Shaft sealing carbon glands are a) lubricated by the main oil
pump b) limited to a temperature of 250 degrees C c) replaced monthly due to erosion d) self-lubricating e)
metal sprayed components c The great majority of steam turbine governing systems utilize the a) hydraulic
system principle b) pneumatic system principle c) mechanical centrifugal principle d) lever principle e)
bi-metal expansion principle b Reaction turbines a) have bucket shaped blades b) have a pressure drop
through the moving and stationary blades c) are used for high pressures only d) have a pressure drop in the
moving blades only e) have little axial d Reaction turbines a) have all of the steam pressure drop take place
in the stationary nozzle b) have a velocity increase in the fixed blading c) are used for higher speed only d)
have a velocity decrease through the fixed blading e) require little blade sealing b In an impulse turbine a)
the steam flow is reduced through the nozzles b) the steam pressure is reduced in the nozzles c) the steam
pressure will drop across the blades d) the steam velocity is increased through the blades e) the exhaust
steam is directed e The steam turbine that has a pressure drop across every set of blades is the __________
turbine. a) double-stage impulse b) single-stage impulse c) topping d) back pressure e) reaction d When
starting a steam turbine it is customary practice to a) analyze the oil for water prior to rolling b) turn on all
cooling water systems first c) place the speed control system in service once the unit is rolling d) test the
over-speed trip as soon as running speed is attained e) stop the auxiliary oil pump as soon as steam begins to
turn the unit d The average amount of water volume which evaporates from a cooling tower is a) 2% b)
10% c) 15% d) 5% e) 3.5% a Natural draft cooling towers operate most effectively in large open spaces and
a) where wind is relatively constant b) where relative humidity is high c) where a large body of water is
nearby d) require a windbreak e) must not be in direct sunlight b Excessive wind velocity in a natural draft
cooling tower may cause a) louvers to become broken b) high water drift or losses c) rotation reversal of the
fan d) over-cooling of the water e) under-cooling of the water c Compared to a cross flow tower, a counter
flow tower a) is not as tall b) has much less capacity c) requires less floor space d) requires more fan power
and CORRECT Answers
Question: should be tested before the turbine is placed in service a) 2, 4, 5 b) 2, 3, 4, 5 c) 1, 2, 4 d) 3, 4, 5 e)
4, 5 b The over speed trip of a steam turbine a) operates on turbine vibrations due to high speed b) is
installed on all turbines c) can be adjusted according to the load demand d) is regulated by exhaust pressure
e) sheds the load in the event of high pressure b Turbine over speed trip a) prevents the turbine from
vibrating b) will close the steam stop valve to the turbine c) is operated by a spring loaded pin in the rotating
blades d) supplies the operator with rpm indications e) reduces the turbine speed by increasing the back
pressure d Turbine lubricating oil a) is not required for small impulse turbines b) must be changed every
four months c) lubricates the blades d) can be used to operate the turbine governor e) should be preheated
before use c The purpose of turbine glands is to prevent a) water from entering the turbine b) steam from
entering the turbine c) steam escaping from the turbine d) steam from entering the lubrication system e) oil
from entering the turbine e Shaft sealing in high output turbines is done with a) water seals b) mechanical
seals c) wear rings d) packing glands e) labyrinth seals b When the steam pressure drop occurs only the
stationary members or components of a turbine, the turbine is known as a) a single stage unit b) an impulse
unit c) a reaction unit d) a Parsons unit e) a cross compound reaction unit e A large reaction turbine will
have a) no thrust bearings b) steam pressure dropping in only the moving sections c) blades which are
basically symmetrical in cross-section d) never more than 5 stages e) steam pressure dropping through
moving and stationary sections e Turbine speed can be "fine tuned" with a device which will be limited to
about 10% over the rated speed. This device is the a) governor valve b) over speed governor c) sentinel
valve d) hand speed control e) over speed trip c Turbine thrust bearings are fixed to the casing and prevent
axial movement of the spindle by contacting a component on the shaft known as a a) shaft sleeve b)
labyrinth c) collar d) shroud e) diaphragm d Shaft sealing carbon glands are a) lubricated by the main oil
pump b) limited to a temperature of 250 degrees C c) replaced monthly due to erosion d) self-lubricating e)
metal sprayed components c The great majority of steam turbine governing systems utilize the a) hydraulic
system principle b) pneumatic system principle c) mechanical centrifugal principle d) lever principle e)
bi-metal expansion principle b Reaction turbines a) have bucket shaped blades b) have a pressure drop
through the moving and stationary blades c) are used for high pressures only d) have a pressure drop in the
moving blades only e) have little axial d Reaction turbines a) have all of the steam pressure drop take place
in the stationary nozzle b) have a velocity increase in the fixed blading c) are used for higher speed only d)
have a velocity decrease through the fixed blading e) require little blade sealing b In an impulse turbine a)
the steam flow is reduced through the nozzles b) the steam pressure is reduced in the nozzles c) the steam
pressure will drop across the blades d) the steam velocity is increased through the blades e) the exhaust
steam is directed e The steam turbine that has a pressure drop across every set of blades is the __________
turbine. a) double-stage impulse b) single-stage impulse c) topping d) back pressure e) reaction d When
starting a steam turbine it is customary practice to a) analyze the oil for water prior to rolling b) turn on all
cooling water systems first c) place the speed control system in service once the unit is rolling d) test the
over-speed trip as soon as running speed is attained e) stop the auxiliary oil pump as soon as steam begins to
turn the unit d The average amount of water volume which evaporates from a cooling tower is a) 2% b)
10% c) 15% d) 5% e) 3.5% a Natural draft cooling towers operate most effectively in large open spaces and
a) where wind is relatively constant b) where relative humidity is high c) where a large body of water is
nearby d) require a windbreak e) must not be in direct sunlight b Excessive wind velocity in a natural draft
cooling tower may cause a) louvers to become broken b) high water drift or losses c) rotation reversal of the
fan d) over-cooling of the water e) under-cooling of the water c Compared to a cross flow tower, a counter
flow tower a) is not as tall b) has much less capacity c) requires less floor space d) requires more fan power
