VectoraLab Lab

Envelope Analysis Overview See the Envelope Analyzer tool and Kurtosis guide for detailed methodology. Key Steps: 1. High-pass or bandpass filter around a resonance (1-20 kHz typical) 2. Rectify and low-pass filter (extract envelope) 3. FFT of the envelope signal 4. Identify BPFO, BPFI, BSF, FTF peaks When to Apply: • Suspected bearing defect (kurtosis elevated) • High-frequency noise observed in raw spectrum • Random impacts in time waveform • RMS trending upward without clear low-frequency cause Filter Selection Tips: • Start with kurtosis maximization across frequency bands (kurtogram) • Alternatively, use known structural resonances as carrier • For steel bearings: 5-20 kHz typical • For polymer/ceramic: may be different Important Notes: • Absence of BPFO/BPFI does not mean no fault — the fault may be at an early stage or the filter band may be wrong • Always cross-check with kurtosis, RMS trend, and physical inspection • BPFO is most commonly seen (outer race is stationary, more consistent impact force)