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36
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January - February 2019
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www
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machinerylubrication.com
TEST YOUR KNOWLEDGE
This month, Machiner y Lubrication continues it s " Test Your Knowledge" sec tion in which we focus on a group of questions from Noria's
Prac tice 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 prac tice test with expanded answers is available at store.noria.com.
ANSWERS
1. C
It is known as elastohydrodynamic lubrication, which is a form of hydrodynamic
lubrication (full-film separation). However, it is called elastohydrodynamic because
the mating surfaces deform elastically (slightly) to enlarge the contact area in order
to carry the load.
2. A
The viscosity index (VI) of oils represents how the viscosity changes with respect to
temperature. VI improvers, which are made from long-chain polymers, are added to
the base oil at concentrations as high as 10 percent for better viscosity/temperature
performance.
3. B
A common sampling frequency for industrial oil would be monthly. Two weeks is
not considered cost-effective, while a sampling frequency of three, six or 12 months
would not be practical, since detecting problems and rectifying them early are
essential to avoid major repairs and in some cases production loss.
1. The deformation of a rolling element to carry a load is
known as what?
A) Boundary lubrication
B) Hydrodynamic lubrication
C) Elastohydrodynamic lubrication
D) Deformative film lubrication
E) Mixed film lubrication
2. Which additive is responsible for giving a multi-
grade lubricant suitable viscosity over wide-ranging
temperature?
A) Viscosity index improver
B) Over-base detergent
C) ZDDP
D) Dispersant
E) Antioxidant
3. A common sampling frequency for an industrial
oil would be:
A) Every two weeks
B) Monthly (500 to 1,000 hours)
C) Quarterly
D) Six months
E) Yearly
