Question 384Steam Plants - 1st Asst/Chief70% to pass
Which of the following statements describes how the main propulsion turbine over speed relay initiates closing of the throttle valve?
AI Explanation
The correct answer is C.
Explanation:
The main propulsion turbine overspeed relay is designed to automatically close the throttle valve in the event of excessive turbine speed. This is typically achieved through a mechanical-hydraulic system, where excessive turbine speed causes an increase in oil pressure that opens a spring-loaded relay valve, which in turn tends to close the steam control valve and reduce the turbine speed. This is the mechanism described in option C, making it the correct answer.
The other options are incorrect because they do not accurately describe the functioning of the main propulsion turbine overspeed relay. Option A describes a centrifugal force-based mechanism, which is not the typical design for this type of system. Option B involves a temperature-based mechanism, which is not the primary method for turbine overspeed protection. Option D describes a weight-based mechanism, which is also not the standard design for a turbine overspeed relay.
Related Questions
#382 While underway on a steam ship, the engineer on watch reports a loss of oil flow in the oil head tank bull's eye. Which of the following should be done? #383 Which of the conditions listed could cause an oil flow sight glass, of a main turbine bearing, to be completely filled with oil? #385 To determine the extent of lube oil system contamination you would _______________.#386 Which of the following would contribute to the formation of an oil and water emulsion, in addition to acid formation? #387 Which of the following conditions may exist if you detect an excessive amount of metal particles on a main engine lube oil strainer magnet?