CMRT CMRT Lubrication and Tribology 3

Question 1

What is the purpose of an EP (Extreme Pressure) additive in a gear lubricant?

Accepted Answer

To chemically react with metal surfaces under high load to prevent welding and scuffing

Answer

To lower the operating temperature of the gear oil

Answer

To increase the oil's viscosity index across temperature ranges

Answer

To inhibit the growth of microorganisms in the lubricant

Question 2

In centralized lubrication systems, what is the role of a divider valve (or metering valve)?

Accepted Answer

To distribute measured, precise amounts of lubricant to multiple points simultaneously

Answer

To filter contaminants from the lubricant before distribution

Answer

To regulate system pressure and prevent over-pressurization

Answer

To signal when the lubricant reservoir is running low

Question 3

What does 'NLGI grade' indicate for a grease product?

Accepted Answer

The consistency (hardness or softness) of the grease as classified by the NLGI

Answer

The National Lubrication Grade Index rating for oxidation resistance

Answer

The base oil viscosity of the grease formulation

Answer

The high-temperature performance rating of the grease

Question 4

Which oil sampling method is most preferred for accurate oil analysis results?

Accepted Answer

Taking a sample from a live zone in the system using a vacuum pump through a dedicated sample port

Answer

Draining oil from the drain plug at the bottom of the sump

Answer

Collecting oil from an oil fill port using a clean container

Answer

Capturing oil from the overflow when the reservoir is overfilled

Question 5

What is the primary purpose of rust and oxidation (R&O) inhibitors in turbine and circulating oils?

Accepted Answer

To protect metal surfaces from rust and slow the chemical degradation of the oil

Answer

To increase the load-carrying capacity of the lubricant under shock loads

Answer

To reduce foam generation in high-speed turbine applications

Answer

To lower the pour point of the oil for cold-start conditions

Question 6

What condition does a high 'acid number' (AN or TAN) in oil analysis indicate?

Accepted Answer

The oil has undergone significant oxidative degradation and is becoming acidic

Answer

The oil has become contaminated with water

Answer

The additive package is still highly effective

Answer

The oil viscosity has increased beyond acceptable limits