Machinery Lubrication

Machinery Lubrication March April 2016

Machinery Lubrication magazine published by Noria Corporation

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The ability to interpret oil analysis results is crucial for guiding decisions about preventive maintenance activi- ties. Having someone in your organization who can pick up a report and interpret it in the context of the environment is essen- tial. This is a skill that can easily be developed with a minimal investment in training and certification. This article will address the fundamentals of oil analysis and how to interpret the resulting reports. Reviewing the Report Once an analysis is completed, it is important to review the report and interpret the accompanying data. Based on the report, you can determine whether action is needed. The report does not always pinpoint specific problems, but it does provide a starting point for analysis. Each test should be clearly identified. The information usually is organized in a spreadsheet format with numbers indicating the test results. When looking at your reports, the first thing you should do is to ensure that they are indeed your reports. Be certain the report includes your name, lube type, machine manufacturer and machine type. The report should also clearly state your machine and lubricant condition. The laboratory should have a rating system that notifies you of normal, marginal and critical levels. In addition, the report should include comments from the analyst who reviewed your results. These comments will help you gauge the criticality of the problem and provide a suggested course of action. Interpreting Viscosity Results Viscosity is the most common test run on lubricants because it is considered a lubricant's most important property. This test measures a lubricant's resistance to flow at a specific temperature. If a lubri- cant does not have the right viscosity, it cannot perform its functions properly. If the viscosity is not correct for the load, the oil film cannot be established at the friction point. Heat and contamination are also not carried away at the appropriate rates, and the oil cannot adequately protect the component. A lubricant with improper viscosity can lead to overheating, accelerated wear and ultimately the failure of the component. Industrial oils are identified by their ISO viscosity grade (VG). The ISO VG refers to the oil's kinematic viscosity at 40 degrees C. To be categorized at a certain ISO grade, the oil's viscosity must fall within plus or minus 10 percent of the grade. So for an oil to be classified as ISO 100, the viscosity must fall within 90 to 110 centi- stokes (cSt). If the oil's viscosity is within plus or minus 10 percent of its ISO grade, it is considered normal. If the oil's viscosity is greater than plus or minus 10 percent and less than plus or minus 20 percent, it is considered marginal. Viscosity greater than plus or minus 20 percent from grade is critical. Measuring Metals: Elemental Spectroscopy Analyzing an oil analysis report involves understanding the concen- tration of expected and unexpected elements in your oil. Some contaminants are picked up as the oil circulates and splashes off different machine components and surfaces. Other contaminants can By Mat t McMahon, testoil OIL ANALYSIS Oil Analysis Reports How to Interpret 16 | March - April 2016 |

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