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Millwright Mechanics- 2nd Year Clutches and Brakes Exams Prep, Exams of Mechanics

Millwright Mechanics- 2nd Year Clutches and Brakes Exams Prep

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2024/2025

Available from 06/18/2025

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Millwright Mechanics- 2nd Year Clutches and Brakes
Exams Prep
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1. To engage or disengage a driven machine, without starting and stopping
the prime mover: What is the purpose of a clutch?
2. A clutch that depends on interlocking parts for engagement and does not
allow slippage: What is a positive contact clutch?
3. 1. Cannot be engaged at high speeds due to shock loads transmitted upon
engagement
2. It may not be possible to engage unless the driver and driven unit are
completely stopped because the mating parts do not line up: What are the
disadvantages of a positive contact clutch?
4. 1. Square jaw
2. Spiral Jaw
3. Multiple-tooth design: What are the 3 types of positive contact clutches?
5. A clutch that uses interlocking square jaws that lock into mating recesses
in its face member: What is a square jaw clutch?
6. True: True or false. Square jaw clutches are bidirectional.
7. very low speeds: What speeds can a square jaw clutch be engaged?
8. transmitting high torque: A square jaw clutch can be disengaged at any speed
as long as it is not .
9. Speed of the engagement and the resistance of the shaft: What two factors
determine the magnitude of the shock when engaging a square jaw clutch?
10. Manual levers, electric solenoids, or a pneumatic or hydraulic cylinder: -
What is used to actuate a square jaw clutch?
11. A clutch where the jaws a re squre on one side and have a slope on the
opposite: What is a spiral jaw clutch?
12. Yes: Can spiral clutches be engaged at hire speeds than square jaw clutches?
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Exams Prep

  1. To engage or disengage a driven machine, without starting and stopping the prime mover: What is the purpose of a clutch?
  2. A clutch that depends on interlocking parts for engagement and does not allow slippage: What is a positive contact clutch?
    1. Cannot be engaged at high speeds due to shock loads transmitted upon engagement
  3. It may not be possible to engage unless the driver and driven unit are completely stopped because the mating parts do not line up: What are the disadvantages of a positive contact clutch?
    1. Square jaw
  4. Spiral Jaw
  5. Multiple-tooth design: What are the 3 types of positive contact clutches?
  6. A clutch that uses interlocking square jaws that lock into mating recesses in its face member: What is a square jaw clutch?
  7. True: True or false. Square jaw clutches are bidirectional.
  8. very low speeds: What speeds can a square jaw clutch be engaged?
  9. transmitting high torque: A square jaw clutch can be disengaged at any speed as long as it is not.
  10. Speed of the engagement and the resistance of the shaft: What two factors determine the magnitude of the shock when engaging a square jaw clutch?
  11. Manual levers, electric solenoids, or a pneumatic or hydraulic cylinder: - What is used to actuate a square jaw clutch?
  12. A clutch where the jaws a re squre on one side and have a slope on the opposite: What is a spiral jaw clutch?
  13. Yes: Can spiral clutches be engaged at hire speeds than square jaw clutches?

Exams Prep

  1. Splines or being keyed to the shaft: What allows one of the positive contact clutch jaws to slide axially?
  2. Spiral: A clutch drives in one direction only.
  3. Manual levers, electric solenoids, or a pneumatic or hydraulic cylinder: - What is used to actuate a spiral jaw clutch?
  4. A clutch that uses a large number of small gear teeth or serrations to provide engagement: What is a multiple-toothe clutch?
  5. Multiple-tooth clutches: What positive contact clutch is able to engage at the highest speed?
  6. Most oftenly an electric solenoid: What is used to actuate a multiple tooth clutch?
  7. The coefficient of friction between the clutch surfaces and a pressure plat stransmits power between the prime mover and the driven unit.: How does a friction clutch work?

Exams Prep

  1. A set of shoes connected to a shaft that expand outward to engage the inner section of a drum connected to the other shaft: What does an expanding shoe clutch consist of?
  2. By a lever-actuated cam that forces the shoe outward against the inside of the drum: How are expanding shoe clutches usually engaged?
  3. Hand, hydraulic or pneumatic cylinders or electrical solenoid: The mechan- ical linkage on a expanding shoe clutch may be actuated by.
  4. A rim with shoes on an air or oil inflateable bladder forces the shoes inward onto the outside of a drum mounted on the shaft: How does a contracting shoe clutch work?
    1. To allow for inward movement due to the increase or decrease in circum- ference when the clutch is engaged or disengaged.
  5. To allow air flow to dissipate heat: Why are the friction shoes of a contracting shoe clutch mounted in segments?

Exams Prep

  1. Mould, pins or rivet: How are the shoes of a contracting shoe clutch mounted to the bladder backing?
  2. True: True or false. A contracting shoe clutch can be used for very high HP applications.
  3. The shoes grab on one side first and may not fully engage.: What is the effect of misalignment on the shoes of a contracting shoe clutch?
  4. The soft disc that functions as the main wearing surface, allowing for replacement without changing the entire unit.: What does the clutch disc or clutch plate refer to on an axial friction clutch?
  5. The harder plates that sandwich the clutch discs.: What does th pressure plate refer to on an axial friction clutch?
  6. The clutch is under sized: What does rapid wear of a axial friction clutch indicate?
  7. A splined clutch disc that is sandwiched between the spring-loaded pres- sure plate and the flywheel when the clutch is engaged: What does a single disc clutch consist of?
  8. Spring-applied and mechanical release: What method of actuation are used for a single disc clutch?
  9. More than one splined clutch discs that is sandwiched between the spring-loaded pressure plate and the flywheel with a floating plate between the discs.: What does a multiple disc clutch consist of?
  10. More power to be transmitted: What do more plates allow for in a multiple-disc friction clutch?
  11. Spring-applied and mechanical release: What method of actuation are used for a multiple-disc clutch?

Exams Prep

  1. They have a tendancy to grab: Why is a cone clutch used in applications where sudden engagement is acceptable.
  2. A fluid coupling: What is a hydraulic clutch similar to?
  3. A scoop tube is used to control the amount of fluid in the coupling in order to regulate the amount of slip and the output can be disconnected from the input: What is the major difference between the fluid clutch and the fluid coupling?
  4. The impeller throws oil outward, creating a vortex and transmits the energy to the turbine by striking the blades.: How is the turbine turned in a fluid clutch?
  5. Slip: What is it called when the speed of the turbine never quite reaches the spped of the impeller?
    1. Hysteresis
  6. Magnetic particle
  7. Eddy current clutch: What are the three types of electric and magnetic clutches?
    1. No wear problems
  8. Better heat dissapation
  9. Various control devices can be incorporated: What are the advantages non-contact clutches?
  10. They cannot transmit as much torque as friction and mechanical clutches- : What is the disadvantage of electromagnetic clutches?
  11. An electricmagnetic coil (or permanent magnet) on the input rotor: What sis used to generate a magnetic field in the rotor of a hysteresis clutch.
  12. torque: The is propertional to the coil current or mag- netic field of a hysteresis clutch.
  13. When the electromagnetic coil is energized, the metal particles form a link between the input rotor and output housing: How is torque transmitted in

Exams Prep a magnetic particle clutch?

  1. Proportional: The torque produced by the magnetic particle clutch is to the current supplied to the staionary coil.
  2. Soft iron: What material are eddy current clutch rotors made of?
  3. When the field coil is energized, a magnetic flux field is created between the outer and inner drums where the slip begins to develop torque: How do eddy current clutches transmit torque?
  4. The driven member, usually a sprocket, gear or sheave, slips between the friction plates until there an overload condition is no longer present: How does a torque-limiting clutch work?
  5. By varying the torque on the torque adjusting nut or changing the spring pressure: How is the amount of power transmitted controlled on a torque-limiting clutch?

Exams Prep

  1. Permit the rotation of the drive in only one direction.: What is the purpose of a holdback/backstop?
  2. A power control device used to stop the motion of the machine or control speed and direction: What are brakes?
  3. Braking torque: How is brake capacity expressed?
  4. Converts it to heat: What do brakes do with kinetic energy?
  5. The coefficient of friction of the brake material: What does brake effective- ness depend on?
    1. Mechanical
  6. Hydraulic
  7. Electrical: What groups can brakes be classified into?
  8. True: True or false. If a brake has to hold only the load, it does not have to be as robust as one used for dyanmic breaking.

Exams Prep

  1. The brakes need to slow or stop the inertia and mass of the load, as well as all the moving and rotating parts.: What is dynamic braking?
  2. Situations involving personnel safety: In what situations does a braking sys- tem need to be over-designed.
  3. Brakes convert kinetic energy into heat and that heat needs to be ad- equately dissapated so it does not damage the components: Why is heat dissipation important on braking systems?
  4. How often the brakes are used: What is the duty cycle of a brake system?
    1. Disc Brakes
  5. External drum brakes
  6. Internal drum brakes
  7. One-way clutch/brakes: What are the classifications of mechanical brakes?
    1. Rotating disc brakes
  8. Stationary disc brakes: What are the two basic types of disc brakes?
  9. A pressure plate applies pressure to a disc brake made of friction material held between a pressure plate and a staionary plate: How does a stationary disc brake function?
  10. A rotating disc has pressure applied from the the pads held in a caliper on both sides.: How does a rotating disc brake function?
    1. Block brakes
  11. Band brakes
  12. External shoe brakes: What are the 3 types of external drum brakes?
  13. A drum with a block that presses on one side of the drum to create friction and stop the machine.: What is a block brake?
    1. Simple

Exams Prep

    1. The fluid acts as a cooling system to dissipate heat
  1. The fluid amount can be regulated to achieve the desired braking: What is an advantage of a hydraulic brake?
    1. Magnetic particles brakes
  2. Eddy current brakes: What are the two classifications of lectrical brakes?
    1. Stator
  3. Rotor
  4. Coil
  5. Magnetic particles: What 4 main components are found in a magnetic particle brake?
  6. Metal particles bond between the anchored member and the other mem- ber when the coil activates a magnetic field, causing a braking action: How does a magnetic particle brake function?
  7. The intensity of the magnetic field: What determines the degree of braking power on a magnetic particle brake?
  8. Repulsion of same poles: What electrical principle do eddy current brakes rely on?
  9. Mechanical, pneumatic, hydraulic or electrical: What are the methods of activation for braking systems?
  10. As close as possible to reduce wobble: Where should shaft bearings be placed in relation to clutches? Why?
  11. Axial: friction clutches must allow one of the two mating surfaces to move easily on the splines or keys.
  12. False, the square jaw clutch can be engaged only at very slow speeds.: - True or false. The square jaw can be engaged at any speed.

Exams Prep

  1. False, the spiral jaw clutch drives in one direction only: True or false. The spiral jaw clutch is a positive contact clutch that can drive in either direction.
  2. True: True or false. Friction clutches can be engaged at any speed to apply a smooth power transition.
  3. False, wet friction clutches handle high slip conditions better: True or false. Wet friction clutches slip more than dry friction clutches.
  4. True: True or false. Friction plate material is softer than pressure plate material.
  5. True: True or false. Multiple-disc clutches provide more power transmission without greatly increasing clutch diameters.
  6. True: True or false. Air can be used as a clutch engaging medium.
  7. True: True or false. Centrifugal force aids in quick release time for contracting shoe clutches.
  8. True: True or false. A clutch disc or clutch plate can be engaged by springs in a pressure plate, mechanical over-centre mechanism or by air bladder or piston.