Question 529Steam Plants - Assistant Engineer
70% to passWith vacuum up and the main propulsion turbine standing by while awaiting engine orders, it is necessary to roll the unit alternately ahead and astern every five minutes to _______________.
Awarm the astern guarding valve and the low lube oil pressure throttle trip
Breduce the possibility of warping the turbine rotors
Cdistribute the gland sealing steam evenly throughout the glands
Dslowly bring the lube oil and bearings to operating temperature
AI Explanation
The correct answer is B) reduce the possibility of warping the turbine rotors. When a steam turbine has been shut down, the rotors can become warped if they are not rotated periodically. Rotating the turbine unit ahead and astern every 5 minutes helps to prevent this warping by evenly distributing the heat and stresses on the rotors. This regular alternating rotation keeps the rotors from becoming deformed or out of alignment, which could lead to damage when the turbine is restarted. The other answer choices are incorrect because they do not address the primary purpose of the periodic rotation, which is to maintain the integrity of the turbine rotors.
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