CLS Grease Technology & Application 2

Question 1

Which thickener type provides the highest dropping point among common grease thickeners?

Accepted Answer

Bentone (clay)

Answer

Bentone (clay or anhydrous calcium silicate) greases have no true dropping point as they do not melt; they degrade thermally rather than becoming liquid, giving them the highest effective upper temperature limits.

Question 2

What does the worked penetration test (ASTM D217) measure in grease?

Accepted Answer

The depth a standard cone penetrates the grease after 60 strokes of a worker

Answer

Worked penetration (ASTM D217) measures how far a standardized cone penetrates the grease after 60 double strokes in a grease worker, which determines the NLGI consistency grade.

Question 3

What is the main advantage of calcium sulfonate complex grease over conventional lithium complex grease?

Accepted Answer

Inherent EP and rust protection without requiring additives

Answer

Calcium sulfonate complex grease provides inherent extreme pressure (EP) and anti-rust properties due to its unique thickener chemistry, without requiring separate EP and rust-inhibitor additives.

Question 4

In a centralized automatic grease lubrication system, what is a primary advantage over manual re-greasing?

Accepted Answer

Delivery of smaller, more frequent grease quantities while equipment is running

Answer

Centralized automatic systems deliver precise, small quantities of grease at frequent intervals while equipment is running, which maintains optimal lubricant film thickness and reduces waste and over-greasing.

Question 5

What is 'channeling' behavior in grease and why can it be beneficial?

Accepted Answer

Channeling is when grease forms a channel allowing the bearing to run through the grease without churning it, reducing heat generation

Answer

Channeling occurs when a bearing clears a path through the grease, allowing it to operate with minimal grease churning, which reduces energy losses and heat generation in high-speed applications.

(CLS) Certified Lubrication Specialist Practice Test

(CLS) Certified Lubrication Specialist Practice Test

CLS Grease Technology & Application 2