Active Dynamic Brake
Model ADB-2

In the traditional configuration of the Leesona winder the process of slowing the spindle to a stop for doff or after a yarn break has occurred is accomplished by draining off the kinetic energy of the spinning package. This "braking effect" is created by "dumping" this energy, in the form of electric current produced by the motor’s spinning armature, into a fixed-value resistor. The energy is then dissipated by the resistor in the form of heat.

In this approach the energy available to be dissipated is greatest at the instant the winder goes into the STOP mode and decreases inverse exponentially as the motor slows. So, maximum braking force is applied suddenly and diminishes rapidly. This is just the reverse of what is needed to effect a gentle, yet rapid speed decrease without sudden shock to the package. It’s like slamming on the brakes in your car then releasing the pedal quickly instead of slowly pressing the brake pedal to the floor to gently stop.

Also, the bale roller is driven only by its contact with the outside layer of the yarn, so when a rapid decrease in the speed of the package occurs the inertia of the bale roller tends to keep it spinning. This generates friction with the outside layer of the yarn and causes yarn deformation or "scuffing".

The ADB-2 is an add-on option for the Selectronics Model LWC-392 motor drive control. It provides a controlled linear decreasing braking force for the spindle when the STOP or YARN BREAK mode is initiated. This provides gentle braking action of the spinning yarn package to eliminate package shift or bale roller scuffing of the perimeter of the yarn package, but yet provide the quickest possible full stop.

The ADB-2 does not use a "dump" or "shunt" resistor to dissipate the energy but instead generates a reverse active energy to accomplish braking. The energy that is generated is proportional to instantaneous speed of the spindle. The ADB-2 monitors this energy as feedback and uses it to provide closed-loop control to assure linear braking force no matter what the mass of the package on the spindle or what speed from which it started decelerating.

The "braking rate" is internally adjustable by a potentiometer and may be set to the most desirable braking profile for any application. It may be "factory-set" by Selectronics to a standard value upon request.

Adjusting the potentiometer clockwise gives a slower ramp up (rate) of the braking force and thus longer time to stop. Of course counter-clockwise is faster ramp, quicker stop although not as gentle on the package.

For more information about this product, please contact us.