ABSA 3B2 Exam | Questions with Verified Answers |
Latest 2025/2026.
A dummy piston is used on a steam turbine to: - ...(ANSWERS)....Counter end
thrust
The entrance angle of a reaction blade is: - ...(ANSWERS)....Almost 90 degrees
To ensure a tight seal, a steam turbine balance piston is fitted with _____. -
...(ANSWERS)....Labyrinth seals
Extraction turbines are turbines where steam is extracted at one or more points
at constant: - ...(ANSWERS)....Pressure
In a steam turbine having pressure drop across the moving blades, an unbalanced
_____ thrust will be developed upon the rotor. - ...(ANSWERS)....Axial
All large disc rotors are machined from __________ steel: - ...(ANSWERS)....A
solid forging of nickel steel.
Convergent-divergent nozzles are used when: - ...(ANSWERS)....High pressure
drops are required
During start up of a steam turbine the thrust block is pushed against a stop in the
direction of the exhaust for: - ...(ANSWERS)....Maximum blade clearance
,In a steam turbine using velocity compounding _____ expand(s) the steam from
initial to exhaust pressure. - ...(ANSWERS)....One set of nozzles
A thrust adjusting gear: - ...(ANSWERS)....Positions the turbine rotor axially
A hollow drum rotor of a steam turbine is machined both outside and inside. How
is the drum end cover with shaft installed in the rotor? - ...(ANSWERS)....Shrink
fitted and welded
Steam turbine casing joints are made steam tight by matching _____ exactly. -
...(ANSWERS)....Flange faces
A back-pressure turbine with exhaust steam going to an old boiler header that is
supplying steam to an old lower pressure turbine is called a: -
...(ANSWERS)....Topping turbine
A reaction turbine has: - ...(ANSWERS)....Rows of stationary blades alternating
with rows of moving blades
When disc rotors are assembled, the discs are heated until they are easily slid
along the shaft and then located in the correct position on the shaft and shaft key.
A small clearance between the discs prevents: - ...(ANSWERS)....Thermal stress in
the shaft
,The purpose of compounding in a steam turbine is to: - ...(ANSWERS)....Reduce
steam and blade velocity
On larger turbines the _____ is split in a horizontal direction. -
...(ANSWERS)....Cylinder
The pressure at the outlet from the moving blades is the same as the pressure at
the inlet to the moving blades in a/an __________ turbine. -
...(ANSWERS)....Impulse
In a condensing-bleeder turbine up to 2% of the total steam flow may be bled off.
What is the bleed-steam used for? - ...(ANSWERS)....Feed-water heating
It is general practice to let the thickness of the walls and flanges _____ from inlet
to exhaust end of a steam turbine casing: - ...(ANSWERS)....Decrease
A water seal is used on some steam turbines ________ to insure that no air leaks
in along the shaft: - ...(ANSWERS)....At speeds above 2000 rev/mm
If a turbine is shut down and left at a standstill while still hot, the lower half of the
rotor will cool faster than the upper half. The rotor will "hog", which means it will
___________. - ...(ANSWERS)....Bend upwards
The warm-up time required of a turbine is dependant on: - ...(ANSWERS)....The
size of the turbine
, The advantage of mechanical-hydraulic governors is: -
...(ANSWERS)....Mechanical losses are greatly reduced
In order to supply oil at two different pressures, a typical turbine lube oil system
has: - ...(ANSWERS)....A pressure reducing valve
Overspeed trips: - ...(ANSWERS)....Are independent of the governing system
In a back-pressure turbine the governor is _____ sensitive. -
...(ANSWERS)....Pressure
On startup of a large condensing turbine, the cooling water to the oil cooler is
turned on: - ...(ANSWERS)....When the oil reaches normal operating
temperatures
In an overspeed trip the spring loaded tripping bolt has a center of gravity: -
...(ANSWERS)....Towards the head end of the bolt
Turbines used to drive auxiliary equipment are usually lubricated by: -
...(ANSWERS)....Ring-oiled bearings
A mechanical overspeed trip is designed to _____ in the event of an overspeed
condition. - ...(ANSWERS)....Shut off the turbine's steam supply
Latest 2025/2026.
A dummy piston is used on a steam turbine to: - ...(ANSWERS)....Counter end
thrust
The entrance angle of a reaction blade is: - ...(ANSWERS)....Almost 90 degrees
To ensure a tight seal, a steam turbine balance piston is fitted with _____. -
...(ANSWERS)....Labyrinth seals
Extraction turbines are turbines where steam is extracted at one or more points
at constant: - ...(ANSWERS)....Pressure
In a steam turbine having pressure drop across the moving blades, an unbalanced
_____ thrust will be developed upon the rotor. - ...(ANSWERS)....Axial
All large disc rotors are machined from __________ steel: - ...(ANSWERS)....A
solid forging of nickel steel.
Convergent-divergent nozzles are used when: - ...(ANSWERS)....High pressure
drops are required
During start up of a steam turbine the thrust block is pushed against a stop in the
direction of the exhaust for: - ...(ANSWERS)....Maximum blade clearance
,In a steam turbine using velocity compounding _____ expand(s) the steam from
initial to exhaust pressure. - ...(ANSWERS)....One set of nozzles
A thrust adjusting gear: - ...(ANSWERS)....Positions the turbine rotor axially
A hollow drum rotor of a steam turbine is machined both outside and inside. How
is the drum end cover with shaft installed in the rotor? - ...(ANSWERS)....Shrink
fitted and welded
Steam turbine casing joints are made steam tight by matching _____ exactly. -
...(ANSWERS)....Flange faces
A back-pressure turbine with exhaust steam going to an old boiler header that is
supplying steam to an old lower pressure turbine is called a: -
...(ANSWERS)....Topping turbine
A reaction turbine has: - ...(ANSWERS)....Rows of stationary blades alternating
with rows of moving blades
When disc rotors are assembled, the discs are heated until they are easily slid
along the shaft and then located in the correct position on the shaft and shaft key.
A small clearance between the discs prevents: - ...(ANSWERS)....Thermal stress in
the shaft
,The purpose of compounding in a steam turbine is to: - ...(ANSWERS)....Reduce
steam and blade velocity
On larger turbines the _____ is split in a horizontal direction. -
...(ANSWERS)....Cylinder
The pressure at the outlet from the moving blades is the same as the pressure at
the inlet to the moving blades in a/an __________ turbine. -
...(ANSWERS)....Impulse
In a condensing-bleeder turbine up to 2% of the total steam flow may be bled off.
What is the bleed-steam used for? - ...(ANSWERS)....Feed-water heating
It is general practice to let the thickness of the walls and flanges _____ from inlet
to exhaust end of a steam turbine casing: - ...(ANSWERS)....Decrease
A water seal is used on some steam turbines ________ to insure that no air leaks
in along the shaft: - ...(ANSWERS)....At speeds above 2000 rev/mm
If a turbine is shut down and left at a standstill while still hot, the lower half of the
rotor will cool faster than the upper half. The rotor will "hog", which means it will
___________. - ...(ANSWERS)....Bend upwards
The warm-up time required of a turbine is dependant on: - ...(ANSWERS)....The
size of the turbine
, The advantage of mechanical-hydraulic governors is: -
...(ANSWERS)....Mechanical losses are greatly reduced
In order to supply oil at two different pressures, a typical turbine lube oil system
has: - ...(ANSWERS)....A pressure reducing valve
Overspeed trips: - ...(ANSWERS)....Are independent of the governing system
In a back-pressure turbine the governor is _____ sensitive. -
...(ANSWERS)....Pressure
On startup of a large condensing turbine, the cooling water to the oil cooler is
turned on: - ...(ANSWERS)....When the oil reaches normal operating
temperatures
In an overspeed trip the spring loaded tripping bolt has a center of gravity: -
...(ANSWERS)....Towards the head end of the bolt
Turbines used to drive auxiliary equipment are usually lubricated by: -
...(ANSWERS)....Ring-oiled bearings
A mechanical overspeed trip is designed to _____ in the event of an overspeed
condition. - ...(ANSWERS)....Shut off the turbine's steam supply
