🔍 Key Concepts

• Main propulsion steam turbine construction – especially rotors, blades, and casings • Causes of mechanical versus operating vibrations in rotating machinery • Effect of temperature gradients and uneven expansion on rotating shafts

💭 Think About

• Which of these choices would create an unbalanced or distorted rotor rather than just changing normal operating conditions? • Think about what specifically would cause the rotor to wobble, bend, or go out of alignment as it turns at high speed. • Which options mainly affect performance/efficiency, and which one directly affects the physical shape or alignment of rotating parts?

✅ Before You Answer

• Identify which option would cause unequal expansion in different parts of the rotor or casing. • Ask: Does this factor produce a mechanical imbalance (out-of-balance rotation) or mainly a change in pressure/vacuum conditions? • Confirm which condition is most directly tied to thermal stresses and shaft distortion, both classic sources of vibration.