Question 157Steam Plants - QMED70% to pass
What statement concerning the operation of a propulsion steam turbine turning (jacking) gear is true?
AI Explanation
The correct answer is B. The turning gear is used to prevent turbine rotor distortion while warming-through or while cooling, since distortion is an issue when warming-through or cooling.
This is because the rapid expansion and contraction of the turbine rotor during the warming-through and cooling processes can lead to distortion of the rotor if it is not properly supported. The turning gear slowly rotates the turbine, gearing, and shaft to evenly distribute the thermal stresses and prevent uneven expansion or contraction that could damage the turbine. Using the turning gear during both warming-through and cooling is necessary to protect the turbine from rotor distortion.
The other options are incorrect because they do not fully capture the purpose and use of the turning gear to prevent turbine rotor distortion during both the warming-through and cooling processes.
Related Questions
#155 The jacking gear on main propulsion turbines can be used to _______________.#156 Under what circumstances would a propulsion steam turbine turning (jacking) gear most likely be used? #158 The jacking gear must be engaged as quickly as possible when securing the main turbines in order to _______________.#159 What statement is true concerning a propulsion steam turbine turning (jacking) gear? #160 Magnets are installed in the main propulsion turbine lube oil strainers to attract metal particles released through wearing of the _______________.