Maintenance stop scheduled after indication of early failure

The PROGNOST®-Predictor system showed increasing Confidence Factor values on the HFE spectrum for the Bearing Bottom Torsion Shaft on August 07th in 2016 first. Within the following months the confidence still kept on a high level till the beginning of November, when the amplitude showed the first higher peaks. On November 05th, the amplitudes violated all thresholds and the acceleration grew from 0.1 m/sec² to 2 m/sec². After the final maintenance work at the end of November the amplitude and Confidence Factor values returned to good condtion. Finally, you see on the last analysis picture the early recognition of HFE 10-20 kHz in relation to the HFE 5-10 kHz and the acceleration spectra.

Analysis view of changing HFE trend

Everything fine 1
Everything Fine
Increased Confidence
Increased Confidence
Increasing Amplitudes
Increasing Amplitudes
Strong Increasing
Strong Increasing Amplitudes
Strong Increasing 2
Strong Increasing Amplitudes
Load Decreased
Load Decreased
After Maintenance
After Maintenance
Comparison HFE and Acceleration Trend
Analysis – HFE & Acceleration Trend

Findings and Learnings

Findings
  • Slow increasing indications
    • First confidence in HFE
    • Than amplitudes in HFE
    • Later on confidence in acceleration spectrum
  • Different probes confirmed the issue
  • Decisions to stop was done in cooperation with the customer, the OEM and PROGNOST Systems

At the past we had some big incidents with this gearbox because it was very difficult to analyze the vibrations with spot measurements. The PROGNOST® system has proven itself as a very reliable monitoring system!!
Also the open communication with the PROGNOST team and Coperion was a big plus in this case.
This way, I want to let you know that we appreciate the open communication, involvement and quick response from PROGNOST ….!”