Machinery Lubrication

Machinery Lubrication November December 2015

Machinery Lubrication magazine published by Noria Corporation

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Page 43 of 85

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 TEST YOUR KNOWLEDGE Answers 1. C Sulfur-phosphorus extreme pressure (EP) additive systems are chemically aggressive and work at high temperatures generated from high loading. Under high loads and associated high temperatures, sulfur-phosphorus EP additives form an adherent surface film that transforms to a ductile, metal soap sacrificial film to help protect gear components from wear. 2. D Because of the non-woven media structure, depth filters generally have inconsistent pore sizes and high dirt-holding capacity. Thus, the correct answer is D. 3. D Both simple and complex soaps consist of long-chain fatty acids and metal hydroxide. The main difference between simple and complex soaps is the presence of short-chain fatty acids in complex soaps. This improves the thermal stability of the thickener and leads to higher dropping points and thus higher operating temperatures. The dropping point of a grease is the temperature at which it passes from a semi-solid to a liquid state under specific test conditions. 1. The lubricant formulation most commonly used for industrial, heavily loaded gear systems is: A) R&O gear oil B) Zinc-phosphorus anti-wear (AW) C) Sulfur-phosphorus extreme pressure (EP) D) 000 EP grease E) Compounded gear oils 2. Depth filters: A) Involve a torturous path between fibers with high dirt-holding capacity B) Are made using square-weave wire cloth C) Have pores of inconsistent sizes D) Answers A and C E) All of the above 3. What is the prime advantage to newer "complex" soap thickeners vs. older simple soap thickeners? A) Higher cost B) More appealing color C) Harder grease D) Higher dropping point and thus higher operating temperature E) Better low-temperature pumping

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