Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/490438
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 store.noria.com. TEsT YoUR knoWlEdgE Answers 1. C Boundary lubrication is defined as that regime of lubrication in which the load is carried by the surface asperities rather than by the lubricant. Elastohydrodynamic lubrication is a form of hydrodynamic lubrication (full-film separation). It is called elastohydrodynamic because the lubricated components deform elastically due to high pressure as in anti-friction bearings, gears and cams. Hydrodynamic lubrication is also called full-film lubrication in which the load is carried totally by the lubricant. The hydrodynamic film is a result of the relative movement of surfaces and the viscous resistance of the lubricant. Mixed-film lubrication is a combina- tion of full-film and boundary lubrication. In this type, the lubricant is insufficient to carry the load and provide full-film separation. Some points of contact still occur between surfaces. 2. D The source of wear metals is the working parts. Therefore, the sample should be collected from the return line downstream of these parts and before the concentration is altered by filters or diluted by reservoir fluid. 3. C All of these options are base oil types except antioxidant, which is an additive that is added to the base oil to improve oxidation stability. www.machinerylubrication.com | March - April 2015 | 25 oil flow 1. Which of the following is not a lubrication regime (mode/type)? A) Boundary B) Elastohydrodynamic C) Boundarydynamic D) Hydrodynamic E) Mixed film 2. Sampling for wear metals in a large multi-component circulating system with a reservoir should be done where? A) Downstream of the pump, upstream of the main pressure-line filter B) Downstream of the reservoir, upstream of the pump (before the pump) C) Downstream of the main pressure-line filter D) From the return line, downstream of the working parts E) From the reservoir 3. Which is not a type of base oil (base stock)? A) Mineral B) Synthetic C) Antioxidant D) Vegetable E) Group III synthetic