Define linear velocity, angular velocity, absolute velocity and state the relation between linear velocity and angular velocity.
2015 SUMMER
Explain with neat sketch working principle of Oldham’s coupling.
When the driving shaft A is rotated, the flange C (link 1) causes the intermediate piece (link 4) to rotate at the same angle through which the flange has rotated, and it further rotates the flange D (link 3) at the same angle and thus the shaft B rotates. Hence links 1, 3 and 4 have the same angular velocity at every instant. A little consideration will show that there is a sliding motion between the link 4 and each of the other links 1 and 3.
Differentiate machine and structure on any four points.
Compare cross belt drive and open belt drive on the basis of .........
Comparison between cross belt drive and open belt drive :
Explain working principle of clutch. State its location in transmission system of an automobile.
A friction clutch has its principal application in the transmission of power of shafts and machines, which must be started and stopped frequently. The force of friction is used to start the driven shaft from rest and gradually brings it up to the proper speed without excessive slipping of the friction surfaces. In automobiles, friction clutch is used to connect the engine to the driven shaft. In operating such a clutch, care should be taken so that the friction surfaces engage easily and gradually brings the driven shaft up to proper speed.
Define completely constrained motion and successfully constrained motion with neat sketch. State one example of each.
Why is balancing of rotating parts necessary for high speed engines ?
The high speed of engines and other machines is a common phenomenon now-a-days. It is, therefore, very essential that all the rotating and reciprocating parts should be completely balanced as far as possible. If these parts are not properly balanced, the dynamic forces are set up.
Give the classification of dynamometer. State the function of it.
Function of dynamometer: A dynamometer is a brake but in addition it has a device to measure the frictional resistance. Knowing the frictional resistance, we may obtain the torque transmitted and hence the power of the engine.
Absorption type dynamometers:
1. Prony brake dynamometer, and 2. Rope brake dynamometer.
Transmission type dynamometers
1. Epicyclic-train dynamometer, 2. Belt transmission dynamometer, and 3. Torsion dynamometer.
State four applications of flywheel.
Applications of flywheel : Used in Internal combustion engines, press machines, mills, punching machines.
State the function of Governor in an I.C. engine.
The function of a governor is to regulate the mean speed of an engine, when there are variations in the load e.g. when the load on an engine increases, its speed decreases, therefore it becomes necessary to increase the supply of working fluid. On the other hand, when the load on the engine decreases, its speed increases and thus less working fluid is required. The governor automatically controls the supply of working fluid to the engine with the varying load conditions and keeps the mean speed within certain limits.
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