VectoraLab Lab

Gear Mesh Frequency (GMF) GMF = Shaft Speed (Hz) × Number of Teeth In a healthy gear, the GMF and its harmonics are present in the spectrum at predictable amplitudes. Fault Indicators: • Elevated GMF or harmonics • Sidebands around GMF spaced at shaft frequency: GMF ± n×f_shaft • Ghost frequencies: from pitch errors during manufacturing • Noise floor elevation across broad band Types of Gear Faults and Their Signatures: • Tooth wear: elevated GMF + harmonics • Tooth breakage: strong sidebands + impacting in time domain • Eccentricity: amplitude modulation at shaft frequency • Misalignment: elevated 2X shaft + GMF sidebands Time Synchronous Averaging (TSA): Averaging synchronised to shaft rotation removes asynchronous noise and highlights gear mesh components. Powerful for early gear fault detection. Important: Gear spectra are complex. Sideband analysis requires careful accounting of all gear/shaft frequencies in the drivetrain.