Machinery Lubrication

Machinery Lubrication Jan Feb 2013

Machinery Lubrication magazine published by Noria Corporation

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Page 29 of 76

ML TEST your KNOWLEDGE This month, Machinery Lubrication continues its "Test Your Knowledge" section in which we focus on a group of questions from Noria's Practice Exam for Level I Machine Lubrication Technician and Machine Lubricant Analyst. The answers are located at the bottom of this page. The complete 126-question practice test with expanded answers is available at 1. The deformation of a rolling element to carry a load is known as what? A) B) C) D) E) Boundary lubrication Hydrodynamic lubrication Elastohydrodynamic lubrication Deformative film lubrication Mixed film lubrication 2. Which additive is responsible for giving a multi-grade lubricant suitable viscosity over wide-ranging temperature? A) B) C) D) E) Viscosity index improver Over-base detergent ZDDP Dispersant Antioxidant 3. A common sampling frequency for an industrial oil would be: A) B) C) D) E) Every two weeks Monthly (500 to 1,000 hours) Quarterly Six months Yearly Answers: 1. C It is known as elastohydrodynamic lubrication, which is a form of hydrodynamic lubrication (full-film separation). However, it is called elastohydrodynamic because the mating surfaces deform elastically (slightly) to enlarge the contact area in order to carry the load. 2. A The viscosity index (VI) of oils represents how the viscosity changes with respect to temperature. VI improvers, which are made from long-chain polymers, are added to the base oil at concentrations as high as 10 percent for better viscosity/temperature performance. 3. B A common sampling frequency for industrial oil would be monthly. Two weeks is not considered cost-effective, while a sampling frequency of three, six or 12 months would not be practical, since detecting problems and rectifying them early are essential to avoid major repairs and in some cases production loss. 30 | January - February 2013 |

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