Excessive thrust bearing wear in a main...

🔍 Key Concepts

• Thrust bearing function in a main propulsion turbine and what it physically controls • Which condition would show up earliest and most subtly as wear starts, before serious damage occurs • Difference between direct evidence of rotor axial movement vs indirect symptoms like noise, vibration, or metal in oil

💭 Think About

• Ask yourself: What does a thrust bearing actually limit or control on a turbine rotor, and how could you directly measure that? • Which option describes something you can routinely monitor and trend over time, allowing you to catch wear early, instead of after clear damage has occurred? • For each choice, decide: is this an early, precise indicator of wear, or a late, secondary symptom after the problem has already gotten worse?

✅ Before You Answer

• Identify which choice gives quantitative information about rotor axial position rather than general symptoms • Consider normal engineering watch procedures: what is commonly logged to detect small changes in thrust bearing clearance or position? • Eliminate options that would likely appear only after significant wear, such as clear mechanical interference or contamination already present in the system

Excessive thrust bearing wear in a main propulsion turbine rotor should FIRST become apparent by __________.

taking rotor position indicator readings

an intermittent vibration when changing speed

metal particles in the lube oil purifier

rubbing noises when jacking over the main unit

🔍 Key Concepts

💭 Think About

✅ Before You Answer