Electrical Braking is usually employed in applications to stop a unit driven by motors in an exact position or to have the speed of the driven unit suitably controlled during its deceleration. Electrical braking is used in applications where frequent, quick, accurate or emergency stops are required. Electrical Braking allows smooth stops without any inconvenience to passengers.
When a loaded hoist is lowered, electric braking keeps the speed within safe limits. Otherwise, the machine or drive speed will reach the dangerous values. When a train goes down a steep gradient, electric braking is employed to hold the train speed within the prescribed safe limits. Electrical Braking is more commonly used where active loads are applicable.
In spite of electric braking, the braking force can also be obtained by using mechanical brakes.
Disadvantages of Mechanical Braking
- The main disadvantages of the Mechanical Braking are as follows:-
- It requires frequent maintenance and replacement of brake shoes.
- Braking power is wasted in the form of heat.
In spite of having some disadvantages of mechanical braking, it is also used along with the electric braking to ensure reliable operation of the drive. It is also used to hold the drive at the standstill because many braking methods do not produce torque at standstill condition.
Types of Electrical Braking
There are three types of Electric Braking in a DC motor. They are Regenerative Braking, Dynamic or Rheostatic Braking and Plugging or Reverse Current Braking
For a detailed study of regenerative braking click on the link given below.
Also See: Regenerative Braking
Detail description of Dynamic Braking in given in the article Dynamic Braking or Rheostatic Braking.
For more information on the topic Plugging or Reverse, Current Braking click on the link given below.
Also See: Plugging or Reverse Current Braking