Vibration analysis can provide comparative data of operating condition of rotating machinery. At what positions should such readings be taken at bearing housings and foundations?

Correct Answer: Option B — Vertical, horizontal and axial.

Comprehensive vibration analysis requires measuring displacement, velocity, or acceleration in three orthogonal planes: vertical, horizontal, and axial. This tri-axial approach is essential to capture the full dynamic signature of rotating machinery, allowing technicians to isolate specific faults like imbalance, misalignment, or bearing wear across all degrees of freedom.