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. 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
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September - October 2016
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