On the Relation Between Operating Conditions and Changes in Vibration Signature: A Case Study in Paper Mill
LUND UNIV (SWEDEN)
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To achieve effective diagnosis and prognosis, relevant and reliable data from the surroundings are required in addition to the vibration measurements. The paper classifies stoppage times and highlights the reasons behind them. Also, it discusses the consequential economic losses incurred by unplanned stoppages. Further, it presents a new approach to envelope alarming, which is called dynamic alarm. It is applicable to identical bearings and those of approximately identical vibration signatures. One of the important conclusions from this study is that it is not only the variation in the machine loading which affects the amplitudes of the bearing defect frequencies, but also the machine speed does. Therefore, changes in the machine speed and load should be considered when interpreting vibration spectra. This will improve the effectiveness of vibration diagnosis and prediction of the time to replacement. During the period covered by this study, which is fifty eight days, it was found that the total stoppage time due to unknown reasons was very large and caused appreciable economic losses of about 2,3 millions SEK. The dynamic alarm is shown theoretically to offer later renewal with fewer failures, and therefore lower cost and higher productivity.
- Manufacturing and Industrial Engineering and Control of Production Systems