MACHINERY LUBRICATION- INDIA MARCH-APRIL 2020 | Page 33

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 store.noria.com.
1. Oxidation stability is highest for which of the
following groups?
A) Group I
B) Group II
C) Group III
D) Group IV
E) Fuel oil
2. Thermal breakdown of lubricants typically:
A) Occurs at very high temperatures due to heat alone with an absence of oxygen
B) Is monitored with acid number
C) May result in thermal cracking of the base oil and a decrease in viscosity
D) All of the above
E) Answers A and C
3. Overgreasing is a common problem with higher speed
rolling bearings because:
A) It causes the temperature to rise
B) It causes the grease to mechanically shear down
C) It causes the grease to change color
D) It causes the temperature to decrease
E) It causes the bearings to elastically deform in shape
oxidize and in some cases leads to premature failure.
temperature. The high temperature causes the oil within the grease to rapidly
This is because overgreasing creates high viscous friction, which leads to high
3. A
to a critical drop in viscosity and sometimes flash point.
Thermal breakdown may result in thermal cracking of the base oil, thus leading
oxidation stability tests will not help in monitoring the thermal breakdown of oil.
due to heat alone with or without oxygen present. Acid number and other
Thermal degradation (breakdown) typically occurs at very high temperatures
2. E
Group IV is a PAO synthetic and has high oxidation stability.
1. D
ANSWERS
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