Critical speeds occurring within the...

Critical speeds occurring within the...

Question 1 of 270705eccefa1bacbc34ba4d475dd

Critical speeds occurring within the operating speed range of a main propulsion diesel engine may be changed, or have their damaging effects reduced by a/an __________.

Question 1 of 27070

Q

Critical speeds occurring within the operating speed range of a main propulsion diesel engine may be changed, or have their damaging effects reduced by a/an __________.

🔍 Key Concepts

• torsional vibration in diesel engine crankshafts • devices that absorb or damp vibration versus those that only isolate mounting • how critical speeds relate to natural frequencies of rotating systems

💭 Think About

• Which option is designed to change or damp the twisting vibrations of the crankshaft itself, not just the engine’s motion on its foundation? • Think about which device is usually mounted on the crankshaft or at its free end specifically to deal with critical speed issues. • Which choice would actually reduce the vibration amplitude at resonance, rather than just make the vibration less noticeable to the hull or structure?

✅ Before You Answer

• Identify which component directly addresses torsional (twisting) vibration rather than only vertical or horizontal shaking. • Verify which device is commonly fitted on medium and slow‑speed diesel engines to handle critical crankshaft speeds. • Eliminate options that mainly change supporting conditions or bearing design but do not significantly adjust the crankshaft’s natural frequency or damping.