WHAT IS ELECTRICAL BRAKING ?

What is electrical braking and its types?

Whenever an electric motor or drive is disconnected from the supply. The speed of the motor gradually decreases and becomes zero. Braking is a generic terms used to set a described operating conditions for electric drives. Such as rapid stopping of motor, holding the shaft to a specific position,maintaining the speed to a desired value preventing from over speeding. The process done by electrical equipment is called Electrical braking.

Electrical braking is used more than mechanical braking because of this reasons.

High operating efficiency
No heat emission produced due to friction in mechanical braking
Less maintenance.

During electrical braking, the motor is made to work as a generator, it produces a negative slip and negative torque(braking torque). This is achieved by suitable changing the electrical connections of the motor.

The braking of the drive should be such as to stop the motor at the specified point of time and location, for some safety reasons, doesnt matter whether its electrical or mechanical braking.

If a motor running at some speed is disconnected from the input supply, the only opposing torque will be the load torque. The motor will stop only after the kinetic energy stored in its inertia is dissipated. When either the torque is small or the inertia is large the motor takes long time to stop. In the applications requiring frequent stops stopping time must be decreased by introducing additional opposing torque by means of electrical braking.

In some applications such as traction, lifts rapid, accurate and smooth stops us essential to prevent from accidents.

The different types of electrical braking are:

1. Regenerative braking

2. Dynamic braking

3. Plugging.

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