Can DC motors be used for regenerative braking only?

Question

I am an engineering student working on a machine to tension steel wire rope for maritime uses. The wire rope (max, ~2000m, diameter 44mm) sits (without tension) on a spool (diameter 2m) and has to be winded under tension (150 to 200kN) to a winch on a ship. This means I'll have to find a way to create an opposing torque on the wire rope drum while the wire is being unwinded from it.

One of the ideas I had (with the help of this forum) was to use a DC motor for regenerative braking on the drum, I, however, have very little knowledge about electrical systems and was wondering if this would even be possible in the first place (due to the high torque). And if so, how would I select a DC motor for this application, and what calculations would come in handy for this?

Answer 1

Regeneration is possible in DC Series Motor since the field current cannot be made greater than the armature current. Since the resistance of the field winding is low, a series resistance is connected in the field circuit to limit the current within the safe value.

Answer 2

Unfortunately the answer is not a driven cable drum with dynamic breaking. I suggest you think on a more mundane braking system. Possibly harnessing the ropes own weight to create the tension would be more feasible with the length and size of rope you are using. To explain why I believe the use of dynamic breaking is not viable I have outlined the problems below when used in similar applications.

There are problems with controlling 2 motors (The first un-lapping the steel rope and the second re coiling the steel rope onto the new spool) whilst trying to maintain a constant torque between the 2 sides of the operation, are are immensely complex. Speed variations of the two motors will be required as the spool diameters vary from a larger diameter (full drum to empty drum) and visa versa. Coupled with torque control and as I doubt the steel rope will have much elasticity to help I am certain that you cannot achieve uniform tension on the wound steel rope. Certainly regenerative breaking will not be possible as this only comes into play after the motor exceeds its required speed, hence no braking until you have already lost the required tension. A steel sheet that is coiled has the same problems whilst being coated. Tensioning towers are required at the uncoiling and recoiling sides to keep a constant torque on the strip with complexed control for starting stopping and running the strip and specialised machinery for controlling the lapped coil and the new spool.

However handling coiled strip has advantages over steel cable. With steel rope you will also need to control the way the rope lap's onto the spool so that an even lay is formed across the width of the drum.