K L University 2009 B.E Industrial Production & Engineering Dynamics of machines - Question Paper

time three hrs max marks 60
ans 1 ques. from every unit. ans all units.

unit 1

1) a) distinguish ranging from the static and dynamic balancing.(4m)
b) A radial engine of 3 cylinders is driven by a common crank. the 3 cylinders of the engine are spaced at 120degrees. the stroke is 150mm. length of hte connecting rod is 275mm and the mass of the reciprocating parts per cylinder is 2kg. compute the primary and secondary forces at a crank speed of 1000rpm. (8m)

(or)

2) a) discuss balancing of several masses revolving in the identical plane. (4m)
b) 3 cylinders of an air compressor having their aes at 120degrees to 1 a different and their connecting rods are coupled to a single crank. the stroke is 10 cm and the length of every connecting rod is 15 cm. weight of the reciprocating parts per cylinder is 15 N. determine the primary and secondary force for the engine running at 3000 rpm

unit 2

3) a) elaborate transmission dynamometers? how are they classified? discuss any 1 of them with neat sketch.

b) the driving pulley in a belt transmission dynamometer rotates at 400 rpm. the diameter of the driving pulley is 750mm, where as the diameter of the driven pulley is 250mm. the diameters of the 2 intermediate pulleys which are rotating on pins fixed to the lever are also 250mm. the load W is suspended at a distance of 800mm from the fulcrum. determine 1) the value of W needed to maintain the lever in a horizontal position when power transmitted is eight KW and 2) the value of W, when the belt just starts to slip on the driving pulley. the coefficent of friction is 0.2 and the maximum tension in the belt is 1600N

(or)

4) a) discuss the meaning of the terms 'precessional motion and gyroscopic torque'
b) A scooter together with the rider weighs 20kgs and the center of gravity with the rider is five cm from the fround when the vehicle is vertical. every road wheel weighs 6.5kgs and radius fo gyration 0.15m, the effective rolling diameter 0.35m. the engine rotates at five times the speed of road wheels in the identical sense. the rotating masses of the engine weigh three kgs and have a radius of gyration 0.12m. determine the speed of vehicle in kmph while moving round curve of 25m radius, if the angle of heel to the vertical is 25 degrees to keep it suitable.

unit 3

5) a) With the help of a neat sketch, discuss hurtung governor.
b) the arms of a ports governor are 31.25 cm long and are pivoted on the axis of rotation. Mass of every ball is 7.5kg and the central load is 45kg. determine the equilibrium speed corresponding to radii of 20cm and 25cm

(or)

6) a) derive an expression for the height of porter governor
b) with the help of a neat sketch, discuss hartnell governor

unit 4

7) what is a 'dynamically equivalent system'?
b) in a steam engine the diameter of the piston is 240mm. length of connecting rod is 1500mm and mass of the reciprocating parts 300kg. if the engine is rotating at 125rpm, what would be the magnitude and direction of the inertia force on the crank shaft when the crank has turned through 30 degrees from inner dead centre?

or

8) A vertical single cylinder diesel engine has cylinder 30 cm dia and stroke 45cm. reciprocating parts weigh 2500N. connecting rod is 100cm long and rpm is 240. for 1/6th stroke. if the index of the legal regulations of expansion and compression is 1.35, obtain the torque on the crank shaft when crank makes an angle of 75degrees with idc during the compression stroke.

unit 5

9) the effective turning moment exerted by 2 stroke engine at crank shaft is represented by T(N-m)=8000+1000sin(2@)-2000cos(2@). this cycle repeats for the mass of flywheel is 500kg and its radius of gyration is 75cm. the engine speed is 300rpm. assuming the external resistance as constant, determine
1) the power developed,
2) the total percentage fluctuations of speed and
3) the maximum angular retardation of the flywheel

(or)

10) the turning moment diagram for a petrol engine is drawn to the scales: turning moment 1mm=5Nm; crank angle 1mm=1degree. the turning moment diagram repeats it self at every half revolution of the engine and the areas above and beneath the mean turning moment line taken in order are 295, 685, 40 , 340, 960, 270 mm2. the rotating parts are equivalent to a mass of 36 Kg at a radius of gyration of 15cm. determine the coefficent of fluctuation of speed when the engine runs at 1000 rpm.

Earning:   Approval pending.