In data interpretation, what indicates a potential bearing defect during vibration analysis?

• A. Decreasing high-frequency vibration only.
• B. Stable RMS values with no change.
• C. Increasing high-frequency vibration, elevated RMS values, and characteristic modal signatures.
• D. Lower energy across all bands.

Answer: (C)

Bearing faults show up in vibration data as a mix of high-frequency energy increases, overall energy rise, and patterns that match the bearing’s fault frequencies or structural resonances. When a defect exists, localized impacts as rolling elements pass the defect generate bursts that excite high-frequency components in the signal. As damage progresses, those high-frequency components become more pronounced, pushing up the RMS value because the total vibration energy grows. Additionally, you’ll often detect characteristic fault frequencies—like inner race, outer race, or ball pass frequencies—and related modal signatures in the spectrum, which are telltale signs of bearing involvement. So seeing increasing high-frequency vibration together with elevated RMS values and these characteristic signatures provides the clearest indication of a potential bearing defect.