2. ❖ More than 5 years teaching experience in
GATE,ESE & PSUs.
❖ Expertise Faculty of SOM, MD and Industrial
Engineering
❖ GATE Ranker 4 times.
❖ PSUs Qualified- BARC, NTPC (DT),
UPRVUNL(AE), MPPGCL (JE).
❖ Mentored more then 15,000 students.
❖ Work as a freelancer in many reputed institute
across the India. KRISHANPAL SINGH
ABOUT ME
18. ❖A brake is defined as a mechanical device by means of which artificial frictional resistance
is applied to a moving machine member in order to retard or stop the motion of a
machine.
❖In the process of performing this function, the brake absorbs either kinetic energy of the
moving member or the potential energy or both kinetic and potential energy.
❖The energy absorbed by the brake is converted into heat energy and dissipated to
surrounding.
19.
20. ENERGY ABSORB BY THE BRAKE
❖Kinetic energy absorbed by the brake
kinetic energy of translation
When the motion of the body is a combination of translation and rotation
E = E1 + E2
21. Potential energy absorbed by the brake
P.E. = Mg(h1 – h2)
energy equated to the work done by the brake
E = T. Θ
E- total energy absorbed by the brake
T braking torque (n-m)
θ- angle through which the brake drum rotates during the braking period
22.
23. 1. A solid cast iron disk of mass 1200kg and radius of gyration .353 m, is used as a flywheel.
It is rotating at 350 rpm. It is brought to rest in 1.5s by means of a brake. Calculate
a) the energy absorbed by the brake
b) the torque capacity of the brake
24.
25.
26. 2.A vehicle of mass 1200 kg is moving down the hill at s slope of 1:5 at 72 km / h. It is to
be stopped in a slope distance of 50 m. If the diameter of the tyre is 600 mm, determine the
total energy absorbed by the brake to stop the vehicle.
27.
28.
29.
30. 3. A mass of 2500 kg is lowered at a velocity of 1.5 m/s from the drum. The mass of the drum
is 50 kg and its radius of gyration can be taken as 0.7 m. On applying the brake, the mass is
brought to rest in a distance of 0.5 m. Calculate
(i). The energy absorbed by the brake;
(ii). The torque capacity of the brake.
40. Heat to be dissipated during braking
❖The energy absorbed by the brake is converted into heat, which increases the
temperature at the rubbing surfaces.
❖The temperature rise depends upon the mass of the brake drum assembly, specific heat
of material. This heat must be dissipated into air
E = mc ∆t
41. 5. A flywheel of 100 kg mass and 350 mm radius of gyration is rotating at 500 rpm. It is
brought to rest by means of a brake. The mass of the brake drum assembly is 5 kg. The brake
drum is made of cast-iron (c=460 J/kg°). Assuming that the total heat generated is absorbed
by the brake drum only, calculate the temperature rise.
