🔍 Key Concepts

• Turbo generator rotor construction and how turbine wheels are mounted/integral with the rotor • Use of sound/hammer tests to detect defects in rotating machinery and castings • How cracks or looseness change the vibration and resonance characteristics of metal parts

💭 Think About

• When you tap a solid metal wheel that is in good condition, what kind of sound do you expect and why? • What kind of physical defect would interrupt the continuity of the metal and cause vibration energy to be absorbed instead of ringing clearly? • Which of the listed options would most directly change the natural resonance of the wheel itself, rather than support or attached parts?

✅ Before You Answer

• Focus on which option describes a direct defect in the turbine wheel rather than surrounding parts or operating conditions • Ask yourself which condition would most likely make the wheel behave like separate pieces instead of one continuous ring • Eliminate any options that don’t clearly explain a change in ringing / resonance when the metal is struck