3B2 POWER ENGINEER EXAM
PRACTICE QUESTIONS AND
ANSWERS WITH COMPLETE
SOLUTIONS 100% CORRECT RATED
A+
1. Which of the following are disadvantages of a gas turbine?
1. High manufacturing costs
2. Produces high noise levels
3. Low thermal efficiency
4. Requires several auxiliaries for efficient operation
Select one:
A. 1, 2, 3
B. 1, 3, 4
C. 2, 3, 4
D. 1, 2, 4
E. 1, 2, 3, 4
✔✔ Answer: E. 1, 2, 3, 4
2. What is the most commonly used refrigeration process method?
Select one:
A. Absorption
B. Lithium bromide
C. Water vapor
D. Vapor compression or mechanical
E. Ammonia compression system
✔✔ Answer: D. Vapor compression or mechanical
,3. Which device is installed to help remove moisture and oil from compressed
air?
Select one:
A. Intercooler
B. Oil separator
C. Unloader
D. Expansion tank
E. Aftercooler
✔✔ Answer: E. Aftercooler
In a two-stage refrigeration system, the 1st stage compressor is also known as a
_____ compressor.
Select one:
A. Booster
B. Standby
C. Low volume
D. Extraction
E. Refrigerant -ANSWER ✔✔A
In the rotary vane compressor:
Select one:
A. Vanes close to the central hub by centrifugal force
B. There is a rotor in the exact center of the casing
C. Refrigerant is trapped between the roller and the decreasing volume of the
eccentric casing
D. The rotor oscillates
E. The vanes move in the rotor -ANSWER ✔✔E
,In a gas turbine, there are fewer turbine stages than compressor stages because:
Select one:
A. Energy can be extracted more efficiently in the turbine
B. Turbine blades are bigger so require fewer
C. Higher exhaust temperatures can be tolerated
D. The hot gases occupy more volume
E. Hot exhaust gases are required for the HRSG's -ANSWER ✔✔A
Pressure limiting devices of refrigeration systems shall be connected:
Select one:
A. Between the compressor and the stop valve on the suction side
B. To a blowdown tank
C. Between the inlet of the condenser and the outlet of the receiver
D. Between the compressor and the stop valve on the discharge side
E. To the receiver outlet -ANSWER ✔✔D
The warm-up time required of a turbine is dependant on:
Select one:
A. How quickly the turbine is required
B. The manufacturer's instructions
C. The size of the turbine
D. The type of turbine
E. Whether the steam is dry or wet -ANSWER ✔✔C
_____ compressors require intake and discharge valves.
, Select one:
A. Rotary
B. Centrifugal
C. Sliding vane
D. Rotary lobe
E. Reciprocating -ANSWER ✔✔E
Besides reducing NOx, water injection systems
Select one:
a. stabilize the combustion process, thereby increasing the life of hot section
components
b. help keep the compressor blading clean
c. reduce the gas turbine's thermal efficiency
d. decrease the power output -ANSWER ✔✔C
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.
Select one:
A. Topping
B. Reaction
C. Back pressure
D. Impulse
E. Extraction -ANSWER ✔✔D
A condenser shell may be fitted with an expansion joint if the:
Select one:
PRACTICE QUESTIONS AND
ANSWERS WITH COMPLETE
SOLUTIONS 100% CORRECT RATED
A+
1. Which of the following are disadvantages of a gas turbine?
1. High manufacturing costs
2. Produces high noise levels
3. Low thermal efficiency
4. Requires several auxiliaries for efficient operation
Select one:
A. 1, 2, 3
B. 1, 3, 4
C. 2, 3, 4
D. 1, 2, 4
E. 1, 2, 3, 4
✔✔ Answer: E. 1, 2, 3, 4
2. What is the most commonly used refrigeration process method?
Select one:
A. Absorption
B. Lithium bromide
C. Water vapor
D. Vapor compression or mechanical
E. Ammonia compression system
✔✔ Answer: D. Vapor compression or mechanical
,3. Which device is installed to help remove moisture and oil from compressed
air?
Select one:
A. Intercooler
B. Oil separator
C. Unloader
D. Expansion tank
E. Aftercooler
✔✔ Answer: E. Aftercooler
In a two-stage refrigeration system, the 1st stage compressor is also known as a
_____ compressor.
Select one:
A. Booster
B. Standby
C. Low volume
D. Extraction
E. Refrigerant -ANSWER ✔✔A
In the rotary vane compressor:
Select one:
A. Vanes close to the central hub by centrifugal force
B. There is a rotor in the exact center of the casing
C. Refrigerant is trapped between the roller and the decreasing volume of the
eccentric casing
D. The rotor oscillates
E. The vanes move in the rotor -ANSWER ✔✔E
,In a gas turbine, there are fewer turbine stages than compressor stages because:
Select one:
A. Energy can be extracted more efficiently in the turbine
B. Turbine blades are bigger so require fewer
C. Higher exhaust temperatures can be tolerated
D. The hot gases occupy more volume
E. Hot exhaust gases are required for the HRSG's -ANSWER ✔✔A
Pressure limiting devices of refrigeration systems shall be connected:
Select one:
A. Between the compressor and the stop valve on the suction side
B. To a blowdown tank
C. Between the inlet of the condenser and the outlet of the receiver
D. Between the compressor and the stop valve on the discharge side
E. To the receiver outlet -ANSWER ✔✔D
The warm-up time required of a turbine is dependant on:
Select one:
A. How quickly the turbine is required
B. The manufacturer's instructions
C. The size of the turbine
D. The type of turbine
E. Whether the steam is dry or wet -ANSWER ✔✔C
_____ compressors require intake and discharge valves.
, Select one:
A. Rotary
B. Centrifugal
C. Sliding vane
D. Rotary lobe
E. Reciprocating -ANSWER ✔✔E
Besides reducing NOx, water injection systems
Select one:
a. stabilize the combustion process, thereby increasing the life of hot section
components
b. help keep the compressor blading clean
c. reduce the gas turbine's thermal efficiency
d. decrease the power output -ANSWER ✔✔C
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.
Select one:
A. Topping
B. Reaction
C. Back pressure
D. Impulse
E. Extraction -ANSWER ✔✔D
A condenser shell may be fitted with an expansion joint if the:
Select one:
