Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/1449093
36 | January - February 2022 | www . machinerylubrication.com scans are simple, quick and highly effective — finding something hot or cold that should not be, in comparison with surroundings or with similar mechanical and electrical components. ermal images superimposed on respective visual images facilitate recognition, iden- tification and reporting of possible problems. ermal monitoring is often the best condition monitoring technology to identify and predict potential failure points for electric power connection, transmission and distribution systems. Motion monitoring and analysis include motion amplification, phase analysis, frequency analysis and amplitude analysis using video camera imaging. Proactive uses of motion amplification include monitoring and accepting structural resonance, mechanical timing and synchronous phasing. Motion monitoring, like thermal imaging, takes in thousands of measurements within a field of view for quick identification and severity determination using non-intrusive surveillance. Problems with amplitude, timing and phase are observed, amplified and trended. Spark monitoring and analysis include distinguishing and analyzing radio waves produced from arcs or sparks. Proactive uses of spark detec- tion and analysis include a survey of motor bearings and a survey before opening an electrical enclosure. Predictive uses of spark detection and analysis include trending low voltage spark events and/or high voltage (>1000 V) arc events. Inspect and test includes visual inspection with or without tools. Visual inspection is typically performed during walk-around vibration, oil, thermal, motion and spark monitoring, as well as during preventive and quality control procedures. ese inspections proactively find and correct misapplication, contamination and incorrect adjustments. ey predictively identify failure progression such as substance deposition or procedure misapplication. Case Histories From A Mill The mill has decades of experience w it h v ibra- tion analysis, oil a na lysis and lubrica- t ion. Te a m members are sk i l led a nd h a v e v e r y good tools, and the mill operates with about 97% availability. Root Cause Failure Analysis (RCFA) reports included failed rolls, couplings, seals, bearings, forming wire, cooling tower, driveshafts, nozzle, screen, gears, retainers, switch and belt drives. is figure represents failure mechanisms as a percentage of esti- mated RCFA production and RCFA estimated repair costs: • Adhesion 35% • Fatigue 25% • Corrosion 20% • Electric discharge 10% e photograph in Figure 2 shows the shaft current electric discharge failure of a 600 HP motor bearing. Continuous Improvement Continuous Improve- ment based on facts, such as Root Cause Failure A na ly si s (RCFA) of planned and unplanned repa irs, prov ide s a n oppor tunit y for cost reduction and reliability improvement. e next step for continuous improvement based on RCFA history may call for expanding on-going condition monitoring to cover all the above-listed methodologies. Add the new condition monitoring methods, starting small; demonstrate success and grow to achieve desired continuous improvement objectives. For example, continuous improvement to start-small-and-grow an active vibration analysis, thermography, motion amplification and preventive inspection condition monitoring program requires the addi- tion of oil analysis and spark detection. Start-Small-And-Grow Oil Analysis If RCFAs indicate problematic fatigue and abrasion for bearings and gears, consider start-small-and-grow by using on-site oil analysis to monitor abnormal wear and water contamination. When a ferrous density measurement reveals abnormal wear, use a magnet to retain the debris, and use a camera or microscope to view the debris on the sensor surface. Start-Small- And-Grow Spark Detection If RCFAs indicate issues with electric discharge causing MECHANICAL FAILURE Electric discharge 10% Deposition 5% Abrasion 5% Figure 2