Industrial Gearbox Vibration Analyzer (ISO 10816)

Per ISO 10816, up to 1.4 mm/s RMS is new-machine condition (zone A) and up to 2.8 mm/s is acceptable for unrestricted long-term operation (zone B). Between 2.8 and 4.5 mm/s the machine should be scheduled for corrective maintenance (zone C), and above 4.5 mm/s vibration is severe enough to cause damage (zone D).

Yes, investigate. Audible whine that changes with load usually means gear-mesh frequency energy is rising — early tooth wear or misalignment under torque. Overall RMS velocity dilutes that high-frequency content. Trend an acceleration band around gear-mesh frequency and check the oil for bronze/steel debris.

On the bearing housings on input and output shafts (one reading each), horizontal — as close to the bearing as possible, on stiff metal (never on covers or guards). Take horizontal, vertical and axial readings if you can; use the highest for the ISO grade and always re-measure at the same spot, load and speed.

The usual suspects are gear wear and tooth damage, shaft misalignment across the box, bearing defects, looseness in hold-down bolts and resonance of the case. A frequency spectrum tells them apart: imbalance shows at 1× running speed, misalignment at 2×, bearing defects at non-synchronous frequencies, and looseness as a raised noise floor with harmonics.

Velocity in mm/s RMS, 10–1,000 Hz. ISO 10816 zone tables are defined on broadband RMS velocity because it weights low- and high-frequency faults evenly for general machines. Acceleration (g) suits high-frequency bearing analysis and displacement (µm) suits low-speed machines, but neither maps onto these zone boundaries.