VectoraLab Lab

Pump-Specific Vibration Sources Hydraulic Forces: • Vane Pass Frequency (VPF) = #vanes × RPM/60 • Cavitation: broadband noise + high-frequency random energy • Recirculation: low-frequency, irregular pulsations • Flow turbulence: broadband spectrum Mechanical: • Unbalance: 1X • Shaft misalignment: 1X + 2X (especially coupling) • Bearing defects: BPFO/BPFI envelope analysis • Seal rub: sub-synchronous vibration Cavitation Detection: • Broadband high-frequency noise (2–10 kHz) • Crackling/popping sound • Kurtosis elevated in high-frequency band • NPSH (Net Positive Suction Head) check required Vane Pass Frequency: VPF = N_vanes × f_shaft Elevated VPF can indicate: blade wear, cavitation, hydraulic imbalance Measurement Locations: • Drive-end (DE) and non-drive-end (NDE) bearings • Pump casing (for hydraulic forces) • Discharge piping (pulsation) Important: Pump vibration involves hydraulic, mechanical, and structural sources. Always check process conditions (flow, pressure, NPSH) alongside vibration data.