Machinery Lubrication

Machinery Lubrication September October

Machinery Lubrication magazine published by Noria Corporation

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Page 45 of 69

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. A The acid number and base number are reported in milligrams (mg) of potassium hydroxide (KOH) per gram of oil. This can be confusing because in reality hydrochloric or perchloric acids are used to neutralize alkaline oil in order to measure the base number. The result is a derived value that represents the volume of KOH necessary to neutralize the volume of base number reagent acid required to neutralize the alkaline sample on which the base number is desired (i.e., one unit of base number neutralizes one unit of acid number). 2. B Some additives are multi-functional, such as overbase detergents used in engine oils. These help to control deposits and neutralize harmful acids generated by combustion. Another example is zinc dialkyldithiophosphate (ZDDP), which works as an anti-wear additive and oxidation inhibitor. 3. B NDm values are used to approximate the rolling bearing speed. NDm is calculated using the following formula: NDm = N x (Di + Do) / 2 Where: N = shaft speed in RPM, Di = bearing bore (inner) diameter in millimeters, and Do = bearing outer diameter in millimeters. So, the correct answer is B. 1. Acid number and base number determinations: A) Are reported in the same units, mg of KOH/gram of oil B) Are reported in pH units C) Are reported in ml of HCL per gram of oil D) Are reported in Abs/cm E) Are reported as the same number because they are both neutralization numbers 2. Some additives are capable of: A) Restoring themselves B) Providing more than one function or benefit C) Repairing metal surfaces D) Regenerating/repairing the base oil E) Improving the ISO cleanliness of the oil 3. NDm values: A) Are a measure of greasing volume B) Use rolling bearing RPM and pitch diameter to approximate bearing speed C) Use journal bearing RPM and mean diameter to approximate bearing speed D) Use gear RPM and diameter to determine gear velocity (speed) E) Are a measure of bearing size sometimes called the pitch diameter Twiter Stay Connected With Noria Follow us on Twitter Like us on Facebook Connect with us on LinkedIn /noria-corporation Continue learning with us on YouTube | September - October 2016 | 39

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