- With _________ a series of nozzle valves opens in sequence as the load increases. This type of governing is most efficient and is used for impulse turbines.
a. throttle governing
b. nozzle governing
c. speed governing
d. by-pass governing
e. overload governing
B. nozzle governing
- Throttle governing uses a single large control valve so when the steam is throttled the _______ , thus increasing turbine efficiency.
a. superheat will increase
b. superheat will decrease
c. pressure will increase
d. pressure will stay the same
e. temperature will decrease
A. superheat will increase
- Overload governing is used on ________ turbines.
a. small
b. impulse
c. low pressure
d. reaction
e. impulse and reaction
E. impulse and reaction
- _________________ is the percent change in speed required for load change equal to the rated.
a. Speed governor
b. Governor speed drop
c. Governor speed increase
d. Throttle governing
e. Integral band
B. Governor speed drop
- The two types of Governors used on steam turbines are:
1) Flow sensitive governor 2) Pressure sensitive governor 3) Temperature sensitive governor 4) Speed sensitive governor
a. 2, 4
b. 1, 3
c. 1, 2
d. 3, 4
e. 2, 3
A. 2, 4
2) Pressure sensitive governor
4) Speed sensitive governor
- Back pressure and extraction turbines use _________ in connection with ___________.
1) pressure sensitive governor 2) throttle governing 3) speed sensitive governor 4) by-pass governing
a. 1, 2
b. 1, 3
c. 2, 3
d. 3, 4
e. 4, 1
B. 1, 3
1) pressure sensitive governor
3) speed sensitive governor
- The overspeed trip on a turbine is usually set to trip the mechanism when it reaches ________ of operating speed.
a. 1
b. 1.05
c. 1.1
d. 1.15
e. 1.2
C. 1.1
- In an/a ____________ , the spring loaded tripping bolt has a center of gravity slightly off the centre of the shaft.
a. electric turning gear
b. nozzle
c. barring gear
d. shear pin coupling
e. overspeed trip
E. overspeed trip
- In an overspeed trip the spring loaded tripping bolt has a center of gravity:
a. Concentric with the shaft
b. Towards the nut end of the bolt
c. Towards the condenser end of the shaft
d. Towards the head end of the bolt
e. Towards the centre of the bolt
D. Towards the head end of the bolt
- When a hydraulic overspeed trip operates:
1) High pressure oil forces the main steam valve shut 2) High pressure oil supply is shut off 3) The stop valve oil cylinder drain is closed 4) The stop valve oil cylinder drain is opened 5) A spring closes the main steam valve 6) The pilot drain is closed
a. 1, 3, 6
b. 2, 4, 5
c. 3, 4, 6
d. 2, 4, 6
e. 3, 4, 5
B. 2, 4, 5
2) High pressure oil supply is shut off
4) The stop valve oil cylinder drain is opened
5) A spring closes the main steam valve
