How would you perform vibration analysis to detect bearing faults in motors, and what are the typical indicators in the vibration spectrum?

• A. Visual inspection with no data collection; rely on hearing.
• B. Measure sound with a microphone and infer faults.
• C. Collect baseline vibration data, perform FFT and envelope analysis, inspect for bearing fault frequencies (inner/outer race, ball pass frequencies), look for high-frequency noise and transient bursts indicating looseness or misalignment.
• D. Only measure temperature to infer bearing faults.

Answer: (C)