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A 4-pole shunt motor is lap-wound with 728 conductors, and has a flux of 25 mWb per
pole. The armature takes 50 Amp in current, the resultant demagnetizing effect due to
armature reaction reduces the air gap flux by 5%. What is developed torque of this
motor?
A footing 2m x 2m is to be founded at a depth of 1.5m in a saturated soil of unit weight 19 kN/m3. The soil has an angle of friction, f, of 28o and cohesion, c, of 5kPa. Groundwater level is at a depth of 4m. Assume a factor of safety of 3.0.
⦁ Determine a value for the safe bearing capacity of the foundation.
⦁ If the groundwater level was to rise to the ground surface, determine the new value of safe bearing capacity.
Determine the total thrust on the back of a smooth vertical wall, 8m high, which is supporting granular backfill with bulk unit weight 18kN/m3 and angle of friction of 33 degrees. The soil surface is horizontal and the water table lies 2.2m below ground level. Assume the saturated unit weight of backfill is 22kN/m3 below water table.
A raft foundation subjects its supporting soil to a uniform pressure of 300 kPa. The dimensions of the raft are 6.1m by 15.25m. Determine the vertical stress due to the raft at a depth of 4.58m below it at the central points of the long edges.
A 8m thick layer of medium sand overlies a deep deposit of dense gravel. A series of standard penetration tests carried out through the depth of the sand has established that the average blow count is 26. Further tests show that the gravel has a standard penetration value of N = 52 in the region of the interface with the sand. A precast pile of diameter 300mm is to be driven down through the sand and to penetrate sufficiently into the gravel to give good end bearing. Adopting a safety factor of 3.0, determine the allowable load that the pile will be able to carry.
determine the total charge (a) on line 0 < x < 5 m if pl = \2x2 mc/m
.A cam with minimum radius of 40 mm, rotating clockwise at a uniform speed is to be designed to
give a roller follower at the end of a valve rod, the motions as given below: 1.To rise the valve through
60 mm during120° rotation of the cam; 2.To keep the valve fully raised through next 30°; 3.To lower
the valve during the next 60°; and 4.To keep the valve closed during the rest of the revolution. The
diameter of the roller is 20 mm and diameter of the cam shaft is 25 mm.The displacement of the
follower has to take place with simple harmonic motion. Draw the profile of the when the line of stroke
is along the axis of the cam shaft.
A symmetrical tangent cam operating a roller follower has the following particulars: Radius of the
base circle of cam = 40 mm, roller radius = 20 mm, angle of ascent= 75o
, total lift = 20 mm, speed of
the cam shaft = 300 rpm. Determine: 1.the principle dimensions of the cam; 2.acceleration of the
follower at the beginning of the lift; and 3. acceleration of the follower where straight flank merges
into a circular nose.
.From the following data draw the profile of a cam in which the follower moves with simple harmonic motion (SHM) during
ascent while it moves with uniformly accelerated and decelerated motion during descent.
least radius of cam = 50 mm.,
angle of ascent = 48o
angle of dwell b/w ascent & descent= 48o
angle of descent = 60o
lift of follower = 40 mm.
diameter of roller= 30 mm
If the cam rotates at 360 r.p.m anti-clockwise, find the maximum velocity & acceleration of the follower
during descent. The follower axis passes through the axis of cam shaft.
.A cam is to be designed for a knife edge follower with the following data:
1. Cam lift = 60 mm during 90° of cam rotation with simple harmonic motion.
2. Dwell for the next 30°.
3. During the next 60° of cam rotation, the follower returns to its original position with simple harmonic motion.
4. Dwell during the remaining 180°.Draw the profile of the cam when the line of stroke is
offset 20 mm from the axis of the cam shaft. The radius of the base circle of the cam is 50 mm. Determine the maximum velocity and acceleration of the follower during its ascent and descent, if the cam rotates at 250 r.p.m.
