Machinery Lubrication magazine published by Noria Corporation
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36 Machinery Lubrication Annual Edition | www . machinerylubrication.com Once we have established the wear rate, we can make some financial calculations. Here are three examples: 1. A gearbox has a value of $30,000. It was designed to last 10 years if we keep the oil at the cleanliness level of 19/16/13 and water content at 100 ppm, as prescribed by the manufacturer. If we have managed to keep the water and particles at the prescribed levels, then we will not have gained or lost any value. If we have done this for a year, we will show that there are nine years of life left in the equipment and it is expected to achieve the planned life. 2. We have the same gearbox as above, but we have kept it cleaner than the manufac- turer's specif ication and achieved a 19/15/12. is will give us a wear rate about 10% slower than anticipated in the original design. For our value, we will divide the component cost by the number of days it was designed to be in service, which works out to $8.22 a day. If we have achieved this for a year, we will show that we can expect an extra 36.5 days of service and have gained $300 in value. e calcu- lations are: 365 x 10% = 36.5 and 36.5 x $8.22 = $300.03. We will show a remaining life expectancy of 9 years and 36.5 days. If we continue to maintain that level, we project to get one extra year of life and a value of $3,000. 3. In this scenario, we have not achieved the desired cleanliness level and are wearing 10% faster than normal. We would show after one year that we have lost 36.5 days and $300 in value. If we do not correct the situation, we show that we anticipate one less year of service than designed, and will end up losing $3,000 in value. Please note that it is possible to reduce the wear in the third scenario and that the lost value can be recaptured if the right corrective actions are taken early. is is why it is important to have the proper sample frequency so that the situa- tion can be corrected in a timely manner before too much useful life has been lost. Echoes of Defects: How Vibration Analysis Breaks the Silence When elevated levels of impact and non-synchronous peaks are observed in the vibration spectrum, it raises concerns about the equipment's condition. In this case, the analyst noticed impact levels exceeding 10g at the input shaft of the gearbox, near the drive end. To investigate further, the analyst requested an oil analysis sample and a lift check on the input shaft. To minimize downtime, the oil sample was taken as the first step. e intention was to gather information about the gearbox's health without taking the asset offline. However, the oil analysis report revealed no upward trend in wear metals or gross particle counts, indicating that the gearbox's condition was not deteriorating. Despite the oil analysis results, the analyst proceeded with a lift check on the input shaft, which required the asset to be taken offline. is check involved measuring the clearance at the bearing. e lift check unveiled a clearance of 0.015 inches — well above the specified limit for the unit. As a result, the customer decided to procure a new gearbox, recognizing the presence of a fault. These results clearly demonstrate the importance of understanding both vibration and oil analysis data and recognizing that they can sometimes provide conf licting results. It emphasizes the need for a comprehensive approach to fault diagnosis, where reliance on a single diagnostic technique is not recommended. Ultimately, the diagnosis should be driven by the specific fault within the asset and should not rely solely on one diagnostic technique. Harmonious Interplay: Vibration and Oil Analysis in Problem Diagnosis A vibration analyst noticed gear mesh harmonics on a recent waveform and asked the plant if a recent oil sample was available to share with the lubrication team. e oil sample report showed that an ISO 220 was the current lubricant and in good health, aside from being a bit dirty. e oil analyst noticed the temperature sensor on the vibration probe was at 130 degrees (Fahrenheit) which was probably cooler than the actual oil temperature. A quick inspection of the equipment tag showed that an ISO 320 was called for when temperatures were above 125 degrees F. If only one method of condition moni- toring had been employed, the problem could not have been isolated as quickly. The Bottom Line Utilizing vibration and oil analyses together provides you with complementary information to enhance the overall approach to maintenance — ultimately preventing costly breakdowns and improving equipment performance in the long-term. Monetary and time savings impact can be calculated more accurately, enabling cost justifications for an improved lubrication program. e harmonious interplay between vibration and oil analysis in problem diagnosis illustrates how combining both methods enables quicker and more accurate identifica - tion of issues and offers the necessary, broader blanket of protection than using only one of the two methods alone. ML FAILURE PREVENTION machinerylubrication.com Start Your Free Weekly Machinery Lubrication eNewsletter Subscription!