Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/934530
4 | January - February 2018 | www . machinerylubrication.com monitoring. Remember, "if it ain't broke, don't fix it." A "possible problem" needs to be vetted before you tear down a machine and cause even more serious or real prob- lems. Cautionary alarms should start the vetting process. Nuisance alarms or false positives are always a concern. Oil analysis is far from perfect, and there are many unavoid- able data errors, including false negatives. Exception testing can be extremely useful for confirming an alarm condition and obtaining a better understanding of severity. It involves resampling and running more extensive tests by the lab. Because many exception tests are costly or time-consuming, it is not practical to use them with routine samples. Good examples of exception tests are analytical ferrography and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). 3 Ways to Produce More Alerts As discussed many times in Machinery Lubrication, the primary goal in making lubrication and maintenance decisions is to achieve the optimum reference state (ORS). You are trying to optimize reliability, not maximize it. You seek the reliability you need at the lowest possible cost and distraction. is holds true for producing more alerts. You don't want "alert overkill" but rather an optimized, effective level of cautionary and critical alarms. is can best be done with three methods working in unison: 1. More Frequent Testing and Inspection It's a false promise to expect even the best oil analysis or condition monitoring program to catch incipient faults and root causes if testing or data collection is conducted infrequently. Many machines can fail start to finish in just a matter of hours. Other failure modes may take weeks, months or years. For instance, if the failure development period is two months, a test or inspection interval of two weeks provides real opportunity for early detection. Conversely, a test or inspection interval of two months may not offer an advanced warning at all. Inspection 2.0 is a great strategy for achieving frequent and effective inspection alerts. 2. More Comprehensive Examination You've probably heard the expression, "If all you have is a hammer, everything looks like a nail." is also relates to oil analysis and condition monitoring in AS I SEE IT Figure 1. Fault tree used to troubleshoot the root cause of a large process pump failure Pump Failure Pump Poor Design Or Specification Dirt Contamination Breather Failure No Pressure Differential Gauge No Inspection PM Incompleted PM to Change Pressure Differential Gauge Failed Filter Full Impeller Coupling Other Contamination Degraded Lubricant Filter Failure Filter Failed Bearing(s) Motor Wrong Lubricant Misalignment Seal Failure Incorrect Installation Dirty New Oil