Machinery Lubrication magazine published by Noria Corporation
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nologies converged to catch bearing faults 27 percent of the time. It was noted that while oil analysis caught the faults 40 percent of the time ahead of vibration, eventually vibration analysis would have detected many of these faults as the problems progressed. In research conducted at Monash University in Melbourne, Australia, failure in gearboxes was induced under controlled conditions. These conditions included misalignment, oil contami- nation, tooth fracture and others. During the progression of the failure, the gearboxes were monitored using vibration analysis and oil anal- ysis (ferrous density). At the end of the study, the researchers determined that, on average, oil analysis provided 15 times earlier detection of impending failure compared to vibration anal- ysis. In the case of tooth fracture, oil analysis gave no alarm at all, while vibration alarmed quickly. They further concluded that both are important companion technologies for the best early detection results. The Magic of Frequency and Detectability It's been said many times that early detection requires frequent detection. It doesn't matter how good your technology is; its effectiveness is limited if used infrequently. Even the most basic and unsophisticated technolo- gies can win the day when they are used at short intervals. An example would be smartly performed one-minute daily inspections. Smart frequency beats smart technology. This benefit is seen in Figure 2. The failure development period (FDP) is the time interval between the start of failure and the end of failure. In the illustrated example, the FDP time interval is one month. If failure detection methods (vibration, oil analysis and inspection) are performed less frequently than monthly, the chance of catching early faults is remote. Even monthly monitoring can fail to detect incipient faults 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 E-mail address: jsowards@noria.com MACHINERY LUBRICATION Volume 14 - Issue 4 July-August 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. Machinery Lubrication 3 July - August 2014 | 3 Stay Connected With Noria Follow us on Twitter https://twitter.com/NoriaCorp Like us on Facebook http://www.facebook.com/noriacorp Connect with us on LinkedIn https://www.linkedin.com/company/ noria-corporation Continue learning with us on YouTube http://www.youtube.com/user/noriacorp Weekly Monthly Bimonthly Quarterly Semiannually Start of Failure End of Failure Failure Developments Period (1 month in this example) HIGH LOW DETECTABILITY Sampling Frequency Options Figure 2. How condition monitoring frequency influences failure detectability