Question 334Steam Plants - 1st Asst/Chief

The correct answer is A) taking rotor position indicator readings. Excessive thrust bearing wear in a main propulsion turbine rotor will first become apparent by changes in the rotor position indicator readings. As the thrust bearing wears, the rotor will gradually shift its axial position, which will be detected by the rotor position indicator before other symptoms become noticeable. The other answer choices are incorrect because: B) metal particles in the lube oil purifier would be a later symptom, C) rubbing noises when jacking over the main unit would indicate more severe wear, and D) an intermittent vibration when changing speed could have various causes unrelated to thrust bearing wear.