What is The Braking?
Braking Word comes from Term brake.We all know the brake is a Mechanism to slow or to stop Vehicle, Wheel, Shaft Or Any Moving mechanism.the process of applying brake is called Braking.
Braking Further Classify in Two Main Term
1) Mechanical Braking
2) Electrical Braking
in Mechanical brakes, generating frictional forces as two surfaces rub against each other. 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.
Mechanical brakes are assemblies consisting of mechanical elements for the reducing or stopping of shafts in equipment drives. They use levers or linkages to transmit force from one point to another. Braking slows or stops the movement of the coupled shafts.
Band brakes – the simplest brake configuration, have a metal band lined with heat and wear resistant friction material.
Drum brakes – which are commonly used on automobile rear wheels, work when shoes press against a spinning surface called a drum.
Disc brakes – are constructed of brake pads, a caliper, and a rotor. During operation, the brake pads are squeezed against the rotor.
Cone brakes – are made with a cup and a cone, which is lined with heat and wear resistant material. During actuation, the cone is pressed against the mating cup surface.
in Electrical Braking, whole process is depended on the flux and torque directions.
Brakes are used to reduce the speed of motors. We know that there are various types of motors available like,DC motors, induction motors, synchronous motors, single phase motors etc. and the specification and properties of these motors are different from each other, hence this braking methods also differs from each other. But we can divide braking in to three parts mainly, which are applicable for every type of motors.
Regenerative braking is a system in which the electric motor that normally drives a hybrid or pure electric vehicle is essentially operated in reverse (electrically) during braking. Instead of consuming energy to propel a vehicle, the motor acts as a generator that charges the onboard batteries with electrical energy that would normally be lost as heat through traditional mechanical friction brakes. As the motor “acts in reverse,” it generates electricity. The friction (electrical resistance) assists the normal brake pads in overcoming inertia and helps slow the vehicle.
In plugging Braking, the terminals of supply are reversed, as a result the generator torque also reverses which resists the normal rotation of the motor and as a result the speed decreases. During plugging external resistance is also introduced into the circuit to limit the flowing current. The main disadvantage of this method is that here power is wasted.
In Dynamic Braking, the motor which is at a running condition is disconnected from the source and connected across a resistance. When the motor is disconnected from the source, the rotor keeps rotating due to inertia and it works as a self-excited generator. When the motor works as a generator the flow of the current and torque reverses. During braking to maintain the steady torque sectional resistances are cut out one by one.