FINAL PWEN ABSA PRACTICE 3 Flashcards
A large reaction turbine will have:
a. No thrust bearings.
b. Steam pressure dropping in only the moving sections.
c. Steam pressure dropping through moving and stationary sections.
d. Never more than 5 stages.
e. Blades that are basically symmetrical in cross-sectio
c. Steam pressure dropping through moving and stationary sections.
An essential auxiliary in a gas turbine installation is a/an:
a. Air heater
b. Generator
c. Air dehumidifier
d. Pump
e. Starting motor.
e. Starting motor.
If you desire an oil to flow at a much lower temperature, you would most likely add:
a. A viscosity index improver
b. Pour point depressants
c. A dispersant
d. A thickening agent
e. Low viscosity oil.
b. Pour point depressants
Impulse turbines:
- Have a velocity increase through the nozzles
- Blades have the angle of inlet the same as the outlet
- Could have more than one set of blades
- Are used for low pressure steam only
- May not require a thrust bearing
a. 1, 2, 3, 4
b. 2, 3
c. 1, 3, 4, 5
d. 2, 3, 4
e. 1, 2, 3, 5
e. 1, 2, 3, 5
An anti-friction bearing:
- Is a bearing containing white metal alloy
- Has rolling friction
- Could be a thrust bearing
- Is a sleeve bearing
a. 1, 4
b. 1, 2, 3
c. 2, 3, 4
d. 2, 3
e. 3, 4
d. 2, 3
Four-cycle engine lubrication is usually:
a. Forced by a pump
b. By gravity oilers
c. By the scoop method
d. By the dip tube method
e. By grease fitting
a. Forced by a pump
In a compression ignition engine, the fuel is ignited by:
a. An electric spark
b. The compressed air temperature
c. The atomized fuel
d. A cross-combustor
e. Compressed air pressure.
b. The compressed air temperature
A double-acting pump:
a. Has two pistons on the pump end
b. Will always be driven by the steam pistons
c. Has two pistons on the driver end
d. Will have two slide valves
e. Is a positive displacement pump.
d. Will have two slide valves
A thrust bearing which does not utilize the oil wedge principle of lubrication is the:
a. Michell type
b. Collar type
c. Flotation type
d. Kingsbury type
e. Vertical type
b. Collar type
Proper priming and venting of a pump is important, especially if:
a. The medium being pumped is high temperature
b. The medium being pumped contains suspended solids
c. Oil or other low flash point lubricant is being pumped
d. A mechanical seal is used
e. The pump has a stuffing box and lantern ring.
d. A mechanical seal is used
A centrifugal pump:
a. Will work well with a negative suction head
b. Can discharge to a very high elevation
c. Can lift a fluid from very deep wells
d. Needs a lantern ring when the suction head is low
e. Is mainly used with lubrication systems
d. Needs a lantern ring when the suction head is low
Strainers are found:
a. On the suction side of the pump
b. On the discharge side of the pump
c. Inside the pump
d. On the air vent discharge of the pump
e. In the impeller eye of the pump.
a. On the suction side of the pump
Positive displacement compressors:
a. Could be of the centrifugal type
b. Require a positive water seal
c. Must all use cylinder valves
d. Must all use internal lubrication
e. Could be single stage with three cylinders.
e. Could be single stage with three cylinders.
When inspecting a dismantled bearing, the first indication of a failing bearing is:
a. Cracked balls
b. Roughness
c. Discoloration
d. Rusting or corrosion
e. Tapered rollers.
b. Roughness
A gas turbine performs most effectively if the:
a. Lubricating oil is of the proper viscosity
b. Cooling water temperature is kept low
c. Ambient air temperature is high
d. Ambient air temperature is low
e. Load is added immediately after startin
d. Ambient air temperature is low
The characteristics of good grease are largely determined by:
a. Its thickening agent or “soap”
b. Its consistency
c. The type of oil used in the grease
d. Its protective coating e. Its color
a. Its thickening agent or “soap”
The purpose of a thrust bearing is to:
a. Prevent the shaft from moving with the thrust
b. Prevent the shaft from rotating backwards due to thrust
c. Prevent the shaft from moving in the opposite direction from the thrust
d. Prevent the shaft from excessive stress due to torsion force
e. Create thrust in the opposite direction
a. Prevent the shaft from moving with the thrust
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
c. Steam escaping from the turbine
When replacing or removing an anti-friction ball bearing, the applied force should:
a. Not be transmitted through the bearing balls
b. Always be against the inner race
c. Always be against the outer race
d. Be applied suddenly and fully
e. Be made only after heating the bearing
a. Not be transmitted through the bearing balls
The capacity of a centrifugal pump should only be reduced by:
a. Throttling the suction valve
b. Closing the suction valve
c. Closing both suction and discharge valves
d. Opening the pump casing vent valve
e. Throttling the discharge valve
e. Throttling the discharge valve
An open circuit is one in which:
a. A switch is closed
b. The current flows through the resistance
c. The wires are bare
d. A switch is open
e. Voltage may exit.
d. A switch is open
An insulator is, a material that will not _____ an electrical current:
a. Reduce
b. Retard
c. Resist
d. Slow
e. Conduct
e. Conduct
The equivalent resistance of three resistances of 10 ohms, 25 ohms and 50 ohms connected in parallel is _____ ohms.
a. 0.16
b. 6.25
c. 85
d. 18.75
e. 8.5
b. 6.25
Watt meters measure:
a. Apparent power
b. Power factor
c. Resistance to current flow
d. Coulombs
e. True watts
e. True watts