![]() The viscosity index can also give insight into the type of base oil and its quality. Viscosity indexes, which can be found on most product data sheets, typically range from 90 to 160, but can exceed 400 and be as low as -60. If your operation will have fluctuating loads, speeds, temperatures, etc., it is imperative to select a lubricant with a higher viscosity index. On the other hand, Oil A fluctuates much more and could adversely affect performance at extreme temperatures. Oil B, which has a VI of 150, maintains a viscosity closer to its ISO VG of 150 as temperatures rise and fall. As shown in the chart below, the difference in viscosity index could greatly affect lubricant viscosity and performance: Source: Machinery Lubrication, NoriaĪs temperatures move towards extreme highs and lows, the difference in Oil A and Oil B is magnified. The higher the viscosity index, the greater the stability of the lubricants viscosity. Viscosity index is a unit-less number that is derived by measuring a fluid’s viscosity from 40⁰C to 100⁰C. To account for changing temperatures, the viscosity index was developed to measure viscosity stability as temperatures change. Therefore, it is imperative to take into account average operating temperature when selecting a viscosity. Machine recommendations do not account for operating temperatures and temperature ranges. Viscosity requirements are based on things such as: component design, loads, and speed. Viscosity index is a measure of how much the viscosity will change as temperature rises or falls. However, the ISO Viscosity Grade (VG) is determined at 40⁰C and will fluctuate depending on operating temperature. Viscosity is the most important parameter since the viscosity grade can be the difference between optimal performance and machine breakdown. While researching lubricants, there are many factors to consider in selecting a lubricant: viscosity, flash point, pour point, and oxidation stability.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |