TSSA 4th class B Test Exam Questions With Correct
Answers Newest Update 2026
Unit 1: Lubrication & Bearings (Questions 1–10)
1. Large journal or sleeve bearings have grooves:
A) In the high-pressure area of the bearing babbit
B) In the non-pressure area
C) Cut into the bearing housing
D) For distributing lubricant evenly just after the pressure area
Answer: B
Rationale: Grooves are placed in the non-pressure area to distribute lubricant without interfering with
the oil wedge that forms in the load-bearing zone. Grooves in the pressure area would break the oil film
and cause metal-to-metal contact.
2. What is the normal operating temperature range for an anti-friction bearing?
A) 20°C to 50°C
B) 65°C to 70°C
C) 80°C to 120°C
D) 150°C to 160°C
Answer: B
*Rationale: Anti-friction bearings (ball and roller) normally operate at 65°C to 70°C (150°F to 160°F).
Temperatures above this may indicate over-lubrication, misalignment, or impending failure.*
3. A collar thrust bearing:
A) Is an anti-friction type bearing
B) Can support more load than a Michell thrust bearing
C) Is used with steam turbines only
D) Has boundary lubrication
Answer: D
Rationale: A collar thrust bearing operates under boundary lubrication conditions, meaning there is only
a thin film of lubricant between surfaces. The Michell (tilting pad) bearing is superior for heavy loads as it
develops a full fluid film.
4. Which material is commonly used as a solid lubricant?
, A) Tallow
B) Molybdenum disulfide
C) Lime
D) Sodium carbonate
Answer: B
*Rationale: Molybdenum disulfide (MoS₂) is a widely used solid lubricant due to its low friction
coefficient, high load-carrying capacity, and ability to withstand temperatures up to 350°C. Graphite is
another example.*
5. Lubricants used for high-output steam turbines should be:
A) Fire resistant
B) Mix well with water
C) Have a low pour point
D) Have a very high viscosity
Answer: A
Rationale: Fire resistance is critical for steam turbine lubricants because high-temperature oil leaks onto
hot surfaces could cause fires. Phosphate ester-based synthetic oils are common for this reason.
6. Applying installation forces through the balls of a bearing can cause:
A) Brinelling
B) Bearing misalignment
C) Cracking or breaking of the balls
D) Excessive air gap
Answer: A
Rationale: Brinelling is the permanent indentation of bearing surfaces caused by static overload or
improper installation (e.g., hammering on the bearing race). This creates vibration and noise during
operation.
7. A common cause of anti-friction bearing failure is:
A) Shaft misalignment
B) Over-lubrication
C) Excessive load
D) All of the above
, Answer: D
Rationale: Shaft misalignment causes uneven loading, over-lubrication leads to overheating and grease
breakdown, and excessive load exceeds the bearing's dynamic capacity. All are common failure modes.
8. Oil rings in sleeve bearings:
A) Are used to adjust bearing clearance
B) Lift oil from the reservoir to the shaft
C) Measure oil temperature
D) Filter the oil
Answer: B
Rationale: Oil rings ride loosely on the shaft and dip into an oil reservoir. As the shaft rotates, the ring
turns and carries oil up to the shaft, providing lubrication without a pump.
9. The purpose of a bearing babbit is to:
A) Harden the bearing surface
B) Embed dirt particles and provide a soft wearing surface
C) Reduce the coefficient of friction permanently
D) Increase load capacity
Answer: B
Rationale: Babbitt (tin/lead/antimony alloy) is soft enough to embed small dirt particles (preventing
shaft scoring) and provides a conformable surface that distributes load evenly.
10. A pressure lubricating system for an engine typically uses:
A) Splash only
B) Gravity feed only
C) A gear-type pump and full-flow filter
D) Wick feed
Answer: C
Rationale: Modern engines use a gear-type positive displacement oil pump that draws oil from the sump,
passes it through a full-flow filter, and supplies it under pressure to bearings and other components.
Unit 2: Pumps (Questions 11–20)
11. Which type of pump is most suitable for high-pressure, low-flow applications?
A) Centrifugal pump
B) Axial flow pump
Answers Newest Update 2026
Unit 1: Lubrication & Bearings (Questions 1–10)
1. Large journal or sleeve bearings have grooves:
A) In the high-pressure area of the bearing babbit
B) In the non-pressure area
C) Cut into the bearing housing
D) For distributing lubricant evenly just after the pressure area
Answer: B
Rationale: Grooves are placed in the non-pressure area to distribute lubricant without interfering with
the oil wedge that forms in the load-bearing zone. Grooves in the pressure area would break the oil film
and cause metal-to-metal contact.
2. What is the normal operating temperature range for an anti-friction bearing?
A) 20°C to 50°C
B) 65°C to 70°C
C) 80°C to 120°C
D) 150°C to 160°C
Answer: B
*Rationale: Anti-friction bearings (ball and roller) normally operate at 65°C to 70°C (150°F to 160°F).
Temperatures above this may indicate over-lubrication, misalignment, or impending failure.*
3. A collar thrust bearing:
A) Is an anti-friction type bearing
B) Can support more load than a Michell thrust bearing
C) Is used with steam turbines only
D) Has boundary lubrication
Answer: D
Rationale: A collar thrust bearing operates under boundary lubrication conditions, meaning there is only
a thin film of lubricant between surfaces. The Michell (tilting pad) bearing is superior for heavy loads as it
develops a full fluid film.
4. Which material is commonly used as a solid lubricant?
, A) Tallow
B) Molybdenum disulfide
C) Lime
D) Sodium carbonate
Answer: B
*Rationale: Molybdenum disulfide (MoS₂) is a widely used solid lubricant due to its low friction
coefficient, high load-carrying capacity, and ability to withstand temperatures up to 350°C. Graphite is
another example.*
5. Lubricants used for high-output steam turbines should be:
A) Fire resistant
B) Mix well with water
C) Have a low pour point
D) Have a very high viscosity
Answer: A
Rationale: Fire resistance is critical for steam turbine lubricants because high-temperature oil leaks onto
hot surfaces could cause fires. Phosphate ester-based synthetic oils are common for this reason.
6. Applying installation forces through the balls of a bearing can cause:
A) Brinelling
B) Bearing misalignment
C) Cracking or breaking of the balls
D) Excessive air gap
Answer: A
Rationale: Brinelling is the permanent indentation of bearing surfaces caused by static overload or
improper installation (e.g., hammering on the bearing race). This creates vibration and noise during
operation.
7. A common cause of anti-friction bearing failure is:
A) Shaft misalignment
B) Over-lubrication
C) Excessive load
D) All of the above
, Answer: D
Rationale: Shaft misalignment causes uneven loading, over-lubrication leads to overheating and grease
breakdown, and excessive load exceeds the bearing's dynamic capacity. All are common failure modes.
8. Oil rings in sleeve bearings:
A) Are used to adjust bearing clearance
B) Lift oil from the reservoir to the shaft
C) Measure oil temperature
D) Filter the oil
Answer: B
Rationale: Oil rings ride loosely on the shaft and dip into an oil reservoir. As the shaft rotates, the ring
turns and carries oil up to the shaft, providing lubrication without a pump.
9. The purpose of a bearing babbit is to:
A) Harden the bearing surface
B) Embed dirt particles and provide a soft wearing surface
C) Reduce the coefficient of friction permanently
D) Increase load capacity
Answer: B
Rationale: Babbitt (tin/lead/antimony alloy) is soft enough to embed small dirt particles (preventing
shaft scoring) and provides a conformable surface that distributes load evenly.
10. A pressure lubricating system for an engine typically uses:
A) Splash only
B) Gravity feed only
C) A gear-type pump and full-flow filter
D) Wick feed
Answer: C
Rationale: Modern engines use a gear-type positive displacement oil pump that draws oil from the sump,
passes it through a full-flow filter, and supplies it under pressure to bearings and other components.
Unit 2: Pumps (Questions 11–20)
11. Which type of pump is most suitable for high-pressure, low-flow applications?
A) Centrifugal pump
B) Axial flow pump
