Up Time Magazine- August/September 2008

PeakVue® – The PeakVue method, developed by CSi (Emerson Process Management), provides a spectrum and waveform that is used to detect bearing faults at an early stage. This method does not rely on the sensor mounted resonance, and it has an important difference to the enveloping technique. The analog signal from the sensor is sampled at a very high frequency (102 kHz) in order to capture the short-duration stress waves. Using a peak hold algorithm, the waveform (and resultant spectrum) viewed by the analyst retains the peak levels making it trendable. A high pass filter is used to remove the low frequency, high amplitude signals. As with all the methods, it is important to select the correct filter setting. change as a result. The force of the impacts will be greater, and there will definitely be periodicity to the vibration. Now there is only 5% - 10% of the L10 life remaining. Again you should consider the root causes and check the lubrication; however you should also monitor this bearing more frequently. The high frequency techniques such as Shock Pulse, Spike Energy, airborne ultrasound, and PeakVue will continue to be effective. Enveloping (demodulation) will also be effective, with peaks visible at the bearing forcing frequencies (BPFO, BPFI, BSF and FT – depending on the nature of the fault) along with harmonics. Harmonics of the bearing forcing frequencies may also be visible in the acceleration spectrum, and time waveform analysis may show signs of the fault (especially for lower speed machines). Peaks may be visible in the velocity spectrum, but probably not until late stage two, when the damage is more pronounced. Managing your weight just got easier. The Four Stages of Bearing Failure Bearing failure has been classically described as occurring in four stages. (I personally prefer to expand the description because, from a vibration point of view, we see more than four changes.) Stage One – In stage one, the damage is minor – the bearing still has 10% to 20% of its L10 life. If you were to remove the bearing at this stage you may not see any damage; the damage is predominantly sub-surface. At this stage you should continue to monitor the bearing, but you should also consider, and remedy, the root causes: lubricate the bearing, check the balance and alignment, correct any resonance conditions, and so on. Stress waves will be generated when there is metalto-metal contact, however it may be random (nonperiodic) until sub-surface defects develop. The airborne ultrasound (acoustic emission), Shock Pulse, Spike Energy, PeakVue and enveloping techniques can all be used at this stage, however the level of success will depend greatly on the way the sensor is mounted, and the filter settings chosen. Stage Two – As the fault continues to develop, the sub-surface defects will grow, eventually breaking through to the surface, causing spalls, cracks, flakes, etc. The vibration pattern will gradually Trico’s High-Viscosity Gear & Lube Oil Portable Filter Cart up to 10,000 SUS Introducing the Industrial Gear and Lube Oil Filtration System from Trico designed speciﬁcally for higher viscosity ﬂuids. This recently released product features a substantial viscosity capability of 2000 cSt @ 40oC, making it one of the most versatile ﬁltration systems available. • Conditions lubricants in use • Filters new oil before putting into service • Complements existing system ﬁltration as part of a preventative maintenance program • Transfers new ﬂuids from drums to storage tanks or system reservoirs ELIMINATE YOUR WEIGHT WATCHING WORRIES. CALL TRICO. Figures 4, 5 & 6 – Frequencies and Effective Analysis Techniques for Bearing Fault Stages 1,2 and 3. www.tricocorp.com 800-558-7008 TRICO Filter Cart_Uptime_2.9375x1 1 8/1/07 11:32:54 AM www.uptimemagazine.com 65 http://www.tricocorp.com http://www.uptimemagazine.com

Table of Contents Feed for the Digital Edition of Up Time Magazine- August/September 2008

Up Time Magazine- August/September 2008 Contents Upfront Upclose Information Technology Lubrication Infrared Maintenance Management Motor Testing Precision Maintenance Reliability Ultrasound Vibration Upgrade

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