In vibration analysis, which finding indicates a bearing fault such as a ball bearing fault?

• A. Uniform frequency spectrum.
• B. No vibration.
• C. Specific fault frequencies corresponding to ball bearings.
• D. Only low-frequency components.

Answer: (C)

When a bearing has a defect, it creates repetitive impacts as the balls interact with the fault during each rotation. Those impulses show up as energy at exact, repeatable frequencies that depend on the bearing’s geometry and the shaft speed. In vibration data, you’ll see peaks at the characteristic fault frequencies for ball bearings (inner race, outer race, ball spin, and the cage/ fundamental train frequency). Seeing those specific frequencies in the spectrum is the strongest indication of a bearing fault, because healthy bearings typically don’t produce concentrated spikes at those precise rates.

Uniform or broad spectra suggest no specific fault-related impulses, no vibration indicates no measurable vibration, and predominantly low-frequency content points to other issues such as misalignment or structural resonances rather than a bearing defect.