ROOTCASTLE / ENGINEERING LAB
Gear mesh faults
Changing tooth-contact stiffness excites gear mesh frequency; damage can modulate that excitation.
Mechanism
Changing tooth-contact stiffness excites gear mesh frequency; damage can modulate that excitation.
Typical symptoms
Shaft-spaced sidebands around gear mesh frequency and impacts may appear.
Measurement method
Record tooth counts and shaft speeds; inspect the spectrum and synchronous average at comparable load.
Alternative explanations
Normal load modulation, eccentricity and transmission paths can influence sidebands.
Additional measurements
Tooth-surface inspection, oil particle analysis, load and backlash measurement.
Likely frequency components
GMF = teeth × RPM / 60; GMF ± shaft Hz
Limitations: without speed, load, mounting and transmission-path context, these examples are not diagnoses. Spectrum examples are conceptual, not complete fault models or field measurements.
SIMULATED · NOT LIVE TELEMETRY
Vibration / FFT
Model and assumptions
512 samples; deterministic sinusoids and seeded noise. FFT is one-sided peak amplitude, not RMS. Δf = fs/N. Hann coherent gain is corrected; spectral leakage can remain. The 4.7× component is not a physical bearing-fault model.
Educational model. Results are not sufficient to diagnose a machine or establish safe operating limits.
Further reading: SKF — Vibrations help find faulty components ↗