Four Quadrant operation of DC Drives


  DC Drives.ppt (Size: 3.77 MB / Downloads: 45)

4Q OPERATION: LIFT SYSTEM

Convention
Upward motion of the cage: Positive speed
Weight of the empty cage < Counterweight
Weight of the full-loaded cage > Counterweight

Introduction to electric braking

Braking of Electrical motor is frequently
employed to perform following operation.
(1)To stop a running motor
(2) To stop and run the motor in reverse
direction
(3) To limit the speed of the motor when
it is over hauled by an active load

Comparison of Electrical braking with Mechanical Braking

Mechanical braking cause wear and tear
Electrical braking is smooth and free from wear and tear.
Mechanical breakings are used along with electric braking as a back up protection to avoid accident in case of failure of electric
Braking .

Types of electric braking

In Braking , the motor works as generator
developing a negative torque which opposes
the motion.
There are three types of electric braking
(1) Regenerative Braking
(2) Dynamic braking
(3) Plugging