What action is recommended when instrumentation detects a sudden rise in vibration near the turbine's operating range?

• A. Turbine will stall
• B. Turbine will vibrate violently
• C. Turbine will accelerate uncontrollably
• D. Turbine will overheat

Answer: (B)

A sudden spike in vibration at or near the turbine’s operating speed signals mechanical distress in rotating equipment. As vibration climbs, rotor dynamics can push the system toward large, unstable oscillations, especially near critical speeds; this is what you’d observe as the turbine beginning to vibrate violently. Because such violent vibrations indicate an imminent risk of damage, the protective action is to stop or reduce load and inspect the rotor, bearings, couplings, and alignment to identify and fix the fault. Other outcomes like stalling, runaway acceleration, or overheating describe different failure modes and aren’t the immediate consequence of a vibration surge.