QUESTION 1:(BEARINGS) ( 25 Marks)
1.1
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Name 3 types of equipment which can be used to monitor the condition of a bearing while it is still in operation?
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(3)
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1.2
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1.2.1
1.2.2
1.2.3
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Explain in your own words the following concepts relating to properties of materials:
Embeddability
Compatibility
Conformability
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(6)
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1.3
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Give three (3) disadvantages of plain bearings?
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(3)
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1.4
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Name four(4) disadvantages of antifriction bearings?
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(4)
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1.5
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Two methods are used to install anti-friction bearings. Name them?
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(2)
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1.6
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Name five (5) reasons why plain bearings overheat?
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(5)
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1.7
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What is the maximum heat that can be applied to an anti-friction bearing?
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(2)
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[25]
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QUESTION 2 :(COUPLINGS) ( 19Marks)
2.1
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What is the function of a coupling?
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(2)
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2.2
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Name three (3) types of misalignments when installing couplings?
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(3)
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2.3
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What is the purpose of a Jacking bolt on an electrical motor assembly?
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(2)
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2.4
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Explain what the term “runout” means in relation to alignment of shafts?
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(2)
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2.5
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Couplings are divided into three (3) main groups. List them?
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(3)
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2.6
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Name four (4) places where you will use couplings? Be specific.
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(4)
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2.7
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Which 3 of the following couplings can compensate for misalignment of connecting shafts?
Flange coupling
Raffard Coupling
Chain coupling
Nylon sleeve coupling
Gear coupling
Fluid coupling
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(3)
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[19]
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QUESTION 3 :(BRAKES AND CLUTCHES) ( 10 Marks)
3.1
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Name 4 safety precautions to be applied when working with hydraulic oils of brake and clutch systems?
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(4)
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3.2
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Brake systems can be divided into two categories. Name them?
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(2)
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3.3
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Name 4 faults which will normally occur with brakes and clutches?
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(4)
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[10]
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QUESTION 4 :(BELT DRIVES) ( 6 Marks)
4.1
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The following code is printed on a wedge belt used on a Lathe:
SPA 16N 1340
What does all the symbols stand for?
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(6)
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[6]
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TOTAL
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[60]
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MEMORANDUM Total 60 Marks
QUESTION 1:(BEARINGS) ( 25 Marks)
1.1
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Bearing stethoscope
Vibration monitors
Infrared thermometers
Bearing checkers
Sound level meters (any 3 of above)
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[3]
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1.2
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1.2.1
1.2.2
1.2.3
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It is the ability of a material to absorb any dirt or other contaminants into its surface (2)
It is the ability of a material to resist seizure or ‘welding’ to a shaft (2)
It is the ability of a material to compensate for slight misalignment (2)
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[6]
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1.3
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They require constant and steady lubrication
They require high starting torque
There is metal to metal contact which leads to wear
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[3]
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1.4
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They are noisier than plain bearings
The initial costs is high
They require a larger space to work in
They are only available from suppliers
High accuracy is required when machining shafts and hubs
Bearings cannot be repaired
They consist of moving parts (Any 4 of the above)
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[4]
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1.5
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Press fit
Thermal expansion
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[2]
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1.6
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Excessive load
Insufficient lubrication
Contaminated lubrication
Incorrect lubrication method
Dirt or foreign matter entering the bearing
Bearing worn
Bearing wrongly designed
Poor maintenance
Misalignment of shafts (Any 5 of the above)
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[5]
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1.7
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100 Degrees
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[2]
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QUESTION 2 :(COUPLINGS) ( 19 Marks)
2.1
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A coupling is a device that is used to connect two shafts – one is the driver the other the driven (or any relevant answer)
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[2]
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2.2
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Axial or gap alignment
Radial or parallel alignment
Angular or face alignment
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[3]
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2.3
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A Jacking bolt is used to move machines horizontally on the base. This means that the position of the motor is adjusted. (or any relevant answer)
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[2]
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2.4
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Runout is a slight error in the rotating machine component such as being off-centre or not exactly round
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[2]
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2.5
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Rigid or permanent
Flexible
Self-aligning
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[3]
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2.6
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Between electric motor and pump
Front wheels of a car
Drive shaft of a vehicle (Any relevant answer)
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[4]
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2.7
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Raffard Coupling
Nylon sleeve coupling
Fluid coupling
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[3]
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QUESTION 3 :(BRAKES AND CLUTCHES) ( 10 Marks)
3.1
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Store fluids in clearly marked containers
Clear up spills immediately
If clothing becomes soaked with fluid, then remove immediately
Wash hands after working with fluids
Wear gloves if possible
Dispose used oils responsibly (any 4 of above and or relevant answer)
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[4]
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3.2
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Internal brake system
External brake system
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[2]
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3.3
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Noise
Shudder
Slipping
Overheating
Non-engagement (any 4 of above)
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[4]
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QUESTION 4 :(BELT DRIVES) ( 6 Marks)
4.1
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SP = Wedge Belt (2 Mark)
A = Section (1 Mark)
16N = 16mm narrow belt (2 Marks)
1340 = length (1 Marks)
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[6]
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