Hi all,

I am looking for some sort of guidelines to help me choose on a tension control system for a continuous wire plating process. The wire would have to maintain a very small tension, as it constantly enters and exits many baths or cells.
Inside a cell, the wire is passed through sets of pulleys which enable it to stay inside for the required amount of time at a given running speed. The whole system would have an unwind and rewind for the wire. What concerns me is what to use in between the cells, to pull the wire and to control the tension. I have read about the use of magnetic clutches, capstan drive systems or just the motor itself to do the job. I am not well versed in these systems so I don't what is best for the job.

What would be the best system to use? What are the advantages/ disadvantages?

Thanks.

 

hi
Most likely you have "dancers" to control the motor speed, even between the cells. We produce fiber optics and would have then "2 cells". We use a DC motor connected to an arm of the "dancer" which has a constant current. The current can be regulated to change the amount of tension wanted. The our motors have a very low rotor weight! The dancer resolvers are then connected to the back of the motor.
We can wind/rewind over 30m/s.
later
zan

 

I have done tension applications using our controllers in two ways. One is to use a dancer which moves to maintain tension, with an analog feedback providing the tension input to our PID algorithm. The other is to use just the motors in question, using the analog feedback in conjunction with a position feedback from the motor for dual loop control - tension around
position. Both methods have been successful in
different applications.

Davis Gentry
Applications Engineer
Delta Tau Data Systems

 

We have done tensioning applications on wire applications.

We used Control Techniques Unidrives for these applications (AC) or the Mentor II (DC).

These drives have built in PID function as well as Torque control. You can then set your Torque using a POT (If the torque is constant) or
via a dancer arm.

Frantz Miles
CT Dynamics (SA).
TEL +27 41 4531758
FAX +27 41 4539299
EMAIL [email protected]

 

Being more of a mechanical person, please forgive me if this sounds to simple. Why not look at something like a Nexen air clutch/brake and put what they call a LoCo lining (lo coeffiecient friction) and set the air pressure to achieve the tension you need and then you can turn off the air or hit it harder to do whatever it is that you need in between. They are self adjusting and can sit there all day and run.
This way you can just put a cheap little standard motor and let it go. You may want to get a lockable pressure regulator. It is one thing for the people in the front offices to make these things work but at 2 o'clock Saturday morning it is always good to have something simple that all can understand. Return volleys welcomed...
[email protected]

 

An even simpler version of this is a pot on the dancer arm that goes directly to the potentiometer input of the VFD driving the roll motor.

The required dead-zone of the dancer arm has to match-up to the end-of-travel point of the pot. This works quite well for both unwinding and re-winding applications as long as the pot remains matched to the travel (and you don't care to know where the dancer arm is .

Anthony Kerstens P.Eng.