High-Frequency Impact Energy (Enveloped Acceleration)
High-frequency impact energy is used to detect early-stage mechanical faults by measuring stress waves generated from microscopic impacts within rotating components. These impacts occur well before defects are visible in standard vibration measurements.
This method is commonly applied to identify:
- Rolling element bearing damage
- Gear tooth defects
- Lubrication breakdown (metal-to-metal contact)
Unlike overall vibration, which measures machine motion, this technique focuses on short-duration impact events in the high-frequency range (kHz).
How It Works
- High-frequency signals are isolated using filtering
- Impact events are extracted from the signal
- The processed result represents the energy of repetitive impacts
- Data can be trended or analyzed as a spectrum
This allows both early detection and fault identification as damage progresses.
What It Looks Like in Practice
In early stages, impacts appear as random high-frequency activity.
As the defect develops, impacts become repetitive and begin to form identifiable patterns.
Eventually, these patterns align with calculated bearing fault frequencies.
Modern Processing Methods
- Envelope Spectra (Demodulation)
Extracts repetitive impact frequencies, allowing identification of specific bearing defects. - High-Frequency Impact Energy (gE)
Quantifies overall impact activity for trending and early warning. - Advanced Detection Methods (Vendor-Specific)
Proprietary techniques enhance sensitivity to impact events and improve fault detection in noisy environments.
Practical Application
A motor operating at normal vibration levels shows no issues in standard velocity measurements.
High-frequency impact energy, however, begins to increase:
- Indicates early-stage bearing distress
- No visible defect frequencies yet
Follow-up analysis later reveals identifiable fault frequencies, confirming defect progression.
Application
This method supports:
- Early detection of bearing and gear defects
- Identification of lubrication issues
- Trending of high-frequency impact activity
- Integration with vibration analysis for complete diagnostics
By focusing on the earliest signs of mechanical distress, high-frequency impact energy provides a critical layer of protection within a predictive maintenance program.
Ultrasound → High-Frequency Impact Energy → Envelope Spectrum → Velocity
(Earliest) (Latest)