Machinery Lubrication

Machinery Lubrication Jan-Feb 2018

Machinery Lubrication magazine published by Noria Corporation

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oth oil analysis and vibration analysis are powerful tools when employed to identify defects in rotating machine train elements such as bearings and gears. However, if used together, these tools can become even more beneficial. When the oil analyst and vibration analyst compare notes, use one another's findings to complement their own analysis, and present a cohesive picture of asset health, it creates a more complete analysis of the asset's condition and instills conf idence in the asset owner. However, when the two analysts do not compare notes and present their results independently, the opposite effect is often produced. e asset owner may become confused or frustrated with the apparent lack of coordination or confusion caused by reports with apparent conflicts. is article will provide both good and bad examples of the coordination between these two powerful inspection methods so analysts and asset owners alike can see what to do and what not to do in certain situations. THE PREMISE OF TECHNOLOGY INTERACTION e basic premise of multi-tech- nology inspection programs is that more than one method should be used to confirm or corroborate the findings of another inspection method. For example, within the field of vibration analysis, when the spectra indicate shaft misalignment, the analyst can use phase analysis to validate the data in the spectra. Likewise, when the vibration signa- ture indicates an electrical fault in the rotor of an AC induction motor, online and off line motor testing should be used to corroborate the vibration analysis f indings and provide a more in-depth analysis into the nature of the problem. Never have t wo inspection methods been better suited to complement each other in the validation of rotating machine train defects than have vibration analysis and oil analysis. For many bearing and gear faults, when one technology detects an issue, the other should as well. e findings should also be presented together to form a cohesive narrative about the nature of the problem. Typically, it does not matter which technology was able to find the defect first. In many cases, it will alternate back and forth as to which technology initially discovers the fault. When oil analysis identifies wear metals in the oil, vibration analysis should be spotting the defect as well as any mechanical forces that might have produced the wear, such as misalignment or imbalance. If oil analysis has been reporting excessive ML | January - February 2018 | 7 0 20 40 60 80 100 120 140 160 180 10/30/2015 - 1/19/2016 - 7/27/2016 - 9/12/2016 - 10/20/2016 - 4/18/2016 - 58 18 170 175 96 Iron Iron alarm Iron alert 29 0 3 6 9 12 15 18 21 24 12/22/2015 - 3/23/2016 - 9/22/2016 - 11/14/2016 - 12/9/2016 - 6/17/2016 - 24 24 24 24 24 24 ISO PC>4 ISO PC>4 alarm ISO PC>4 alert Figure 1. Iron content of an oil sample trending upward over time Figure 2. High ISO cleanliness codes for more than a year B

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