Abstract - The vacuum brake was, for many years, used in place of the air brake as the standard, fail-safe, train brake used by railways. Pneumatic braking. Explore Vacuum Braking System with Free Download of Seminar Report and PPT in PDF and DOC Format. Also Explore the Seminar Topics. Vacuum Braking System - Download as Powerpoint Presentation .ppt), PDF File .pdf), Text File .txt) or view presentation slides online.
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Vacuum Braking System, Ask Latest information, Vacuum Braking System Abstract,Vacuum Braking System Report,Vacuum Braking System Presentation ( pdf. TM B, Ordnance Maintenance, Vacuum Brake Systems .. converts from a vacuum system into an air suspended system. faces with fine mill file. The vacuum braking system was developed from above said reasons and the the Vacuum brake system i.e., the loss of vacuum will cause the brake to be.
The basic hydraulic system, most commonly used, usually has six main stages. The brake pedal, the brake boost vacuum servo , the master cylinder, the apportioning valves and finally the road wheel brakes themselves.
The vacuum brake was, for many years, used in place of the air brake as the standard, fail-safe, train brake used by railways. Pneumatic braking systems use compressed air as the force used to push blocks on to wheels. The vacuum brake system is controlled through a brake pipe connecting a brake valve in the driver's cab with braking equipment on every vehicle. A vacuum is created in the pipe by an ejector or exhauster. The ejector removes atmospheric pressure from the brake pipe to create the vacuum using steam on a steam locomotive, or an exhauster, using electric power on other types of train.
With no vacuum the brake is fully applied. The vacuum in the brake pipe is created and maintained by a motor-driven exhauster. The exhauster has two speeds, high speed and low speed.
The high speed is switched in to create a vacuum and thus release the brakes. Slow speed is used to keep the vacuum at the required level to maintain brake release. Vacuum against small leaks in the brake pipe is maintained by it. The brake valve will have at least the following positions: "Release", "Running", "Lap" and "Brake On". The quicker you stop, the more power is required, the more heat is generated 8 Requirement of brakes: The function of brakes is to stop the vehicle within the required time.
The brake of the vehicle absorbs all the energy given by the engine plus that due to the momentum of the vehicle.
This energy must then be dissipated. In most of the vehicles, the energy is absorbed by the brakes in the form of heat and dissipated into the stream of air passing around the vehicle. Apart from stopping the vehicle the brakes should perform the others function too like the vehicle should stop without any jerk and the retardation should be smooth.
Also the rate of retardation should be equal to the pedal effort and the effort applied by the driver to stop the vehicle should not be excessive. The rate of wear should also be low.
The brake system should not be affected by water, heat, and dust etc. It should require a very low maintenance and durable. Coefficient of friction The amount of friction between 2 surfaces pads and rotors or shoes and drums Determined by dividing the force required to pull an object across a surface by the weight of the object 10 Friction 11 Factors Governing Braking Frictional Contact Surface The amount of surface, or area, that is in contact.
Simply put, bigger brakes stop a car more quickly than smaller brakes used on the same car. Heat Dissipation The tremendous heat created by the rubbing brake surfaces must be conducted away from the pad and rotor or shoe and drum and be absorbed by the air.
It must have two independent hydraulic circuits with independent fluid reserves. The brake system must be capable of locking all four 4 wheels, and stopping the vehicle in a straight line. The braking systems must be protected with scatter shields from failure of the drive train A brake pedal over-travel switch must be installed. This switch must kill the ignition and cut the power to any electrical fuel pumps.
The car must be equipped with a red brake light that illuminates when ever the brakes are applied 14 How does a braking system work? When the brake pedal is depressed, the pressure on the brake pedal moves a piston in the master cylinder, forcing the brake fluid from the master cylinder through the brake lines and flexible hoses to the calipers and wheel cylinders. The force applied to the brake pedal produces a proportional force on each of the pistons.
Each output piston pushes the attached friction material against the surface of the rotor or wall of the brake drum, thus slowing down the rotation of the wheel. When pressure on the pedal is released, the pads and shoes return to their released positions.
This action forces the brake fluid back through the flexible hose and tubing to the master cylinder. The stopping power or capacity of a brake depends largely on the surface area of frictional surfaces as well as on the actuation force applied.
The friction and wear encountered by the working surfaces are severe. Thus, the durability of a brake or service life between maintenance depends heavily on the type of material used to line the shoe or pad. The brake pipe and feed pipe run throughout the length of the coach. Brake pipe and feed pipe on consecutive coaches in the train are coupled to one another by means of respective hose couplings to form a continuous air passage from the locomotive to the rear end of the train.