Question 668Steam Plants - Assistant Engineer70% to pass
The main propulsion shaft turning gear usually connects to the free end of the high- speed high-pressure pinion because the _______________.
AI Explanation
The correct answer is D) the greatest gear ratio between the turning gear motor output and bull gear can be obtained.
The main propulsion shaft turning gear is typically connected to the free end of the high-speed, high-pressure pinion because this arrangement allows for the greatest possible gear ratio between the low-speed turning gear motor and the high-speed main propulsion shaft. This higher gear ratio provides the necessary mechanical advantage to slowly rotate the large, heavy main propulsion shaft during maintenance or startup procedures.
The other answer choices are incorrect because they do not directly address the primary purpose of the turning gear arrangement, which is to achieve the most advantageous gear ratio for slowly rotating the main shaft.
Related Questions
#666 The jacking/turning gear mechanism of a main propulsion geared turbine installation is normally connected through mechanical linkage to the _______________.#667 Which of the devices listed is generally used to engage the main engine turning gear to the high-pressure turbine high-speed pinion? #669 The purpose of the sentinel valve installed on a turbine casing is to _______________.#670 Which of the devices listed is found on an LP main propulsion steam turbine casing? #671 Large temperature and pressure drops which occur in the first stage of a combination impulse and reaction turbine are caused by steam passing through _______________.