CMRT CMRT Lubrication and Tribology

Question 1

What does the term 'tribology' refer to in the context of maintenance?

Accepted Answer

The study of friction, wear, and lubrication between interacting surfaces

Answer

Tribology is the science that studies friction, wear, and lubrication of interacting surfaces in relative motion.

Question 2

Which lubrication regime occurs when the lubricant film fully separates the two mating surfaces?

Accepted Answer

Hydrodynamic (full-film) lubrication

Answer

Hydrodynamic (full-film) lubrication occurs when the lubricant film is thick enough to completely separate the mating surfaces, minimizing metal-to-metal contact.

Question 3

What does the viscosity index (VI) of an oil indicate?

Accepted Answer

How much the oil's viscosity changes with temperature

Answer

The viscosity index (VI) indicates how much an oil's viscosity changes with temperature; a higher VI means less viscosity change over a wide temperature range.

Question 4

Which type of grease thickener is most commonly used in industrial bearings due to its high temperature and water-resistance properties?

Accepted Answer

Lithium soap

Answer

Lithium soap is the most widely used grease thickener in industrial applications because it offers a good balance of high-temperature stability, water resistance, and mechanical stability.

Question 5

What does ISO VG 46 mean on a hydraulic oil label?

Accepted Answer

The oil has a nominal kinematic viscosity of 46 cSt at 40°C

Answer

ISO VG (Viscosity Grade) 46 means the oil has a nominal kinematic viscosity of 46 centistokes (cSt) at 40°C as defined by ISO 3448.

(CMRT) Certified Maintenance and Reliability Technician Practice Test

(CMRT) Certified Maintenance and Reliability Technician Practice Test

CMRT CMRT Lubrication and Tribology