Millwright Certification Lubrication Systems and Practices

Question 1

What does the viscosity grade of a lubricating oil describe?

Accepted Answer

The oil's resistance to flow at a given temperature

Answer

Viscosity is a measure of an oil's resistance to flow; higher viscosity oils flow more slowly and are used in higher-load, lower-speed applications.

Question 2

Which type of grease is most commonly used in electric motor bearings operating at high temperatures?

Accepted Answer

Lithium complex grease

Answer

Lithium complex grease has excellent high-temperature stability (dropping point above 260°C/500°F) and is the most widely specified grease for motor bearings.

Question 3

Over-greasing a rolling element bearing is dangerous because it can cause:

Accepted Answer

Excessive heat from churning and possible seal damage

Answer

Excess grease causes the rolling elements to churn through the grease, generating heat, which can degrade the lubricant and damage seals.

Question 4

What is the primary function of a splash lubrication system in a gearbox?

Accepted Answer

To use the rotation of gears to splash oil onto mating surfaces

Answer

Splash lubrication relies on the lower gears dipping into an oil sump and throwing oil onto gear teeth and bearing surfaces through rotation.

Question 5

What does a milky or cloudy appearance in gearbox oil indicate?

Accepted Answer

Water contamination (emulsification)

Answer

Milky or cloudy oil indicates water has mixed with the oil and formed an emulsion, which severely reduces the oil's lubricating ability.

Blog Practice Test

Blog Practice Test

Millwright Certification Lubrication Systems and Practices