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What is plugging?

 What is plugging?

The process of suddenly stopping the running motor by electrical method is called Electrical braking. It is used to stop the motor at a specific position, preventing the motor from over speeding.
 One of the type of electrical braking is called plugging. It is also known as counter current braking.

Plugging is the process of braking the motor by changing the direction of the motor rotation. This direction of rotation of electric motor is dependent on several variables.

For ac machines, the phase sequence of the stator winding are one of the variable and dc machines, the polarities of the field or armature voltage.

In ac machines, the shaft of the machines rotates in the same direction as the magnetic field. This direction of rotation of the field in the air gap depends on the phase sequences connection of the stator windings.

 

When the three phase stator windings are connected in the RYB sequence, the air gap field rotates in one direction at nearer to synchronous speed(slip s=1). When the sequence of the stator windings is changed to RBY (I.e., by interchanging any to terminal of the motor).

 

By this rotor and stator magnetic field rotate in opposite direction. The slip at this condition will be more than 1. here, the direction of torque developed is reversed and the motor begins to slow down until its speed becomes zero.when the speed becomes zero the motor should to disconnected from the supply by some mechanism otherwise it starts to accelerate in the opposite direction.

 

In DC machines, the armature terminal is reversed while running and thereby providing braking as similar to AC machine.

TAKE CARE, CHEERS, BYE


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Location: Bailnadu South R.F., Tamil Nadu, India

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