Machinery Lubrication

Machinery Lubrication March April 2014

Machinery Lubrication magazine published by Noria Corporation

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failure may cause complete machine failure or only partial machine failure, such as dropping the machine's remaining useful life (RUL) from 80 to 40 percent. Conversely, when a machine (or one of its components) fails due to mechan- ical causes, the heat and wear debris produced can completely or partially destroy the oil. Calculating Overall Lubricant Criticality The Overall Lubricant Criticality (OLC) defines the importance of lubricant health and longevity as influenced by the probability of premature lubricant failure and the likely conse- quences (for both the lubricant and the machine). The proposed method for calculating the OLC is shown in Figure 2. Like many such methods, the approach is not an exact science but nevertheless is grounded in solid principles in applied tribology and machine reliability. The calculation is quite simple. Overall Lubri- cant Criticality equals Overall Machine Criticality plus the multiplied product of the Lubricant Crit- icality Factor (LCF) and the Degradation Occurrence Factor (DOF). The OLC is scaled from 1 to 100. All calculated values more than 100 are reduced to the default maximum of 100. As mentioned previously, the OMC was discussed in great detail in the March-April 2013 issue of Machinery Lubrication. It is the multiplied product of the Failure Occurrence Factor (likeli- hood of machine failure) and the Machine Criticality Factor (consequences of machine failure). It is shown again as a matrix in Figure 3. Because lubricant failures are common causes of machine failures, it is no surprise that the OMC plays a significant role in calculating Overall Lubricant Criticality. Lubricant Criticality Factor The LCF defines the specific economic conse- quences of lubricant failure separate from machine failure consequences. The LCF is influ- enced by the cost of the lubricant, the cost of downtime to change the lubricant, flushing costs and system disturbance costs (e.g., the fishbowl effect). For instance, machines that use large volumes of expensive, premium lubri- cants will understandably have high LCF values. It is not unusual for main lube oil systems on turbine generators in power plants to have lubricant investments in the range of hundreds of thousands of dollars. In such cases, the cost of premature lubricant failure can be enormous, not to mention the potential impact on the machine's reliability. Studies have shown the true cost of an oil change can far exceed 10 times the apparent cost (labor and oil costs). The LCF is subjectively scaled from 1 to 10, with 10 representing extremely high criticality. Degradation Occurrence Factor The DOF defines the probability of prema- ture lubricant failure. The conditions that don't Forget lUBrICANt CrItICAlItY when designing oil Analysis Programs Machinery Lubrication 3 March - April 2014 | 3 PUBLISHER Mike Ramsey - mramsey@noria.com GROUP PUBLISHER Brett O'Kelley - bokelley@noria.com EDITOR-IN-CHIEF Jason Sowards - jsowards@noria.com SENIOR EDITOR Jim Fitch - jfitch@noria.com TECHNICAL wRITERS Jeremy Wright - jwright@noria.com Wes Cash - wcash@noria.com Alejandro Meza - ameza@noria.com Bennett Fitch - bfitch@noria.com Loren Green - lgreen@noria.com CREATIvE DIRECTOR Ryan Kiker - rkiker@noria.com GRAPHIC ARTISTS Julia Backus - jbackus@noria.com Terry Kellam - tkellam@noria.com Josh Couch - jcouch@noria.com Patrick Clark - pclark@noria.com ADvERTISING SALES Tim Davidson - tdavidson@noria.com 800-597-5460, ext. 224 MEDIA PRODUCTION MANAGER Ally Katz - akatz@noria.com CORRESPONDENCE You may address articles, case studies, special requests and other correspondence to: Editor-in-chief MACHINERY LUBRICATION Noria Corporation 1328 E. 43rd Court • Tulsa, Oklahoma 74105 Phone: 918-749-1400 Fax: 918-746-0925 Email address: jsowards@noria.com MACHINERY LUBRICATION Volume 14 - Issue 2 March-April 2014 ( USPS 021-695) is published bimonthly by Noria Corporation, 1328 E. 43rd Court, Tulsa, OK 74105-4124. Periodicals postage paid at Tulsa, OK and additional mailing offices. POSTMASTER: Send address changes and form 3579 to MACHINERY LUBRICATION, P.O. BOx 47702, Plymouth, MN 55447-0401. Canada Post International Publica - tions Mail Product (Canadian Distribution) Publications Mail Agreement #40612608. Send returns (Canada) to BleuChip Interna- tional, P.O. Box 25542, London, Ontario, N6C 6B2. SUBSCRIBER SERVICES: The publisher reserves the right to accept or reject any subscription. Send subscription orders, change of address and all subscription-related correspondence to: Noria Corporation, P.O. Box 47702, Plymouth, MN 55447. 800-869-6882 or Fax: 866-658-6156. Copyright © 2014 Noria Corporation. Noria, Machinery Lubrication and associated logos are trademarks of Noria Corporation. All rights reserved. Reproduction in whole or in part in any form or medium without express written permission of Noria Corporation is prohibited. Machinery Lubrication is an independently produced publication of Noria Corporation. Noria Corporation reserves the right, with respect to submissions, to revise, republish and authorize its readers to use the tips and articles submitted for personal and commercial use. The opinions of those interviewed and those who write articles for this magazine are not necessarily shared by Noria Corporation. CONTENT NOTICE: The recommendations and information provided in Machinery Lubrication and its related information properties do not purport to address all of the safety concerns that may exist. It is the respon - sibility of the user to follow appropriate safety and health practices. Further, Noria does not make any representations, warranties, express or implied, regarding the accuracy, completeness or suitability of the information or recommendations provided herewith. Noria shall not be liable for any inju - ries, loss of profits, business, goodwill, data, interruption of business, nor for incidental or consequential merchantability or fitness of purpose, or damages related to the use of information or recommendations provided. Figure 2. The proposed method for calculating Overall Lubricant Criticality

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