Up Time Magazine - December 2008/January 2009 - (Page 29) Product data sheets provide useful information on lubricants and their behavior on ASTM tests which provides ISO 150/220 Moderate speeds 3600 rpm and low loads such as electric motors B B - Bearing width inches Gq = .114 DB D D - Bearing outside diameter inches Figure 1 - Equation to calculate the number of ounces to add to a bearing during greasing. Once the correct viscosity has been determined, the correct lubricant type based on additive composition needs to be selected. Lubricant formulations consist of a base stock and additives. Most base stocks are mineral oils from refining of crude oil. Table 3 summarizes lubricant composition in various lubricant types. Lubricants in Table 3 with ‘o’ signify the additive is not in all formulations but is optional for specific applications. The following summary is best practices to apply in maximizing lubricant quality: • Utilize specification tests on product data sheets to compare lubricants • Contact OEM’s for minimum specification requirements • Set minimum lubricant specifications with suppliers • Set standards on new lubricant deliveries but be reasonable. During the delivery process it is difficult to maintain high levels of cleanliness. Most hydraulic oils need to filtered before use • Utilize certificates of analysis for water content and viscosity on delivered lubricants • Routinely run more extensive tests with an oil analysis laboratory to determine if supplier is meeting minimum requirements • Don’t utilize price as main criteria in supplier selection • Establish return criteria in lubricant contracts Paper Machine √ √ Circulating √ √ Right Quality Once the right type of lubricant has been selected, it is important to select a high quality lubricant. Quality is both the ability of the lubricant to meet OEM specifications based on performance on ASTM tests and the cleanliness of the fluid which is delivered. You can have the highest quality lubricant, but if is not handled properly during delivery or storage it will not perform as expected. Additive Rust Inhibitor Oxidation Inhibitor Extreme Pressure Antiwear Detergents Dispersants Antifoam VI Improver Demulsifiers ο ο ο ο √ ο ο ©Copyright 2006 LTC This calculation will give you the number of ounces to add to a bearing during greasing. This is especially important when greasing electric motors because of the tendency to over grease. In order to add the correct amount, grease guns need to be calibrated on their delivery of number of shots /ounce. This can be completed by using a postage scale to weigh out one ounce of grease. An easier method is to count the number of shots to fill a 35 mm film canister, which is approximately one ounce of grease. Once the guns have been calibrated, try to use the same grease gun type consistently for the same application. Some of the newer guns will indicate the amount being added. Oil Lubrication – Centralized oil systems add the right amount at the right time. This discussion will focus on the having the correct level in oil baths and splash lubricated gear boxes. Many small pumps are lubricated by oil baths as illustrated in Figure 2. The correct level for a bottle oiler bath should be at the middle of the lowest ball. Turbine √ √ Gear √ √ √ Hydraulic √ √ Engine √ √ Right Amount Grease Lubrication – More is not better. Too much lubricant in a system can be as destructive as not enough, as evidenced by the over greasing of electric motors, which happens to be a major failure mode. The use of the formula in Figure 1 will assist in greasing rolling element bearings with the correct amount. √ √ √ √ √ √ √ ο ο ο √ Table 3 - Lubricant Composition by Additive Type Figure 2 - Oil Bath Illustration Courtesy Trico Mfg www.uptimemagazine.com 29 http://www.uptimemagazine.com
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