Wire Drawing m/c using Siemens Master Drive

[allscott]

I completely agree with rdrast on this one. I am afraid I can't offer much help on the Siemens drives but as was pointed out this is a simple dancer control, no magic here and no need for the spooler to have any clue on what the draw is doing.

I am in this business and as a matter of fact can see one of these machines out my office window. I would put pressure on Siemens as high as you can go because it is apparent to me the guys you have at your site don't know what they are doing.

 

[Anshuman Patra]

rdrast ... I have 2 nos of drives for 2 motors.One is the main motor ( Capstan motor which is pulling the wire out of the die chamber ) and the other one ( the spooler motor which is basically spooling the wire on the spools). The spooler drive has the f/b from the dancer arm.

I hope you have this picture of the machine,I am sorry If I was not able to make a clear impression of the machine in my earlier posts

 

[DickDV]

I picture this system as being a wire coming off an unwind spool, passing thru a reducing die, making several wraps around a capstan driven by the capstan drive, and then passing over or under a dancer idler on its way to a windup spool driven with the winder drive.

It sounds like the dancer is there to provide a rough indicator of winding tension for the purpose of approximately constant tension on the winder spool as the diameter changes with material buildup.

Based on the wire draws I have done, I would expect the capstan drive to be a sensorless vector speed regulator with no external control loop and the winder being a sensorless vector with external setpoint control and process feedback from the dancer.

The goal should be to have rock-solid speed regulation on the capstan and stable tension control on the winder.

I think my judgement has to be along with the previous posters that suggest that the Siemens techs simply don't know what they are doing. There isn't any rocket science here, as far as I can see.

Definitely, raise a fuss up the Siemens ladder a ways with the goal of getting an experienced tech to set up your system.

 

[allscott]

What DickDV is describing is exactly what I am picturing as well, we have 4 of these machines at this plant. The only difference is that there is several reducing dies, not just one.

Most of the bobbin winders here use a sensoreless vector drive with simple torque control. There is also a provision for an adjustable max speed (pot) in the event of a wire break.

Our fastest draw can run up to 1500m/min and is the only one that uses a dancer. The dancer output is feeding a PID in the drive that is controlling torque.

The Siemens guys seem to be concentrating on synchronizing the two drives when there is no good reason to even try to do that.

Your OP stated that you were just upgrading some older DC drives, I can guarantee you they weren't synced together. What makes them think the new system should be any different?

 

[rangerfreak]

Finally! Something I have a little knowledge about.

I work for a wire manufacturer with line speeds reaching 7000 fpm.

The drawing machine has several capstans inside that are of different sizes and locations for different string-up configurations. There are, I believe, either 7 or 8 dies per wire size. Each capstan turns at different speeds to compensate for wire diameter and stretch.
The dancer is there for 2 main reasons. Tension, to keep the wire taught on the capstans, and speed feedback. Our dancers uses a 10 turn 10K high accuracy potientometer on the back of the dancer for the speed feedback. The speed feedback is fed directly to our siemens drives.


Our drives are not connected together directly. Once everything is up and running, your set speed and takeup speed should be within a few hundred feet per minute of each other. The stretch of the wire makes it nearly impossible to get it exact.

I hope this helps you somewhat. I wish I could tell you more exact specs as far as which model of drives we use, but I am at home now and my memory is eluding me right now. I can tell you that our drawing machine is powered by a 400 hp DC motor, The annealler is powered by a 150 hp DC motor, and if memory serves me right, The takeup is powered by a 50 hp DC motor, but that one may be wrong. If you need more exact info, just let me know and I will get everything I can for you!

Good luck!
Mark

 

[allscott]

50 HP for a bobbin take up on a drawing machine sounds awfully big, ours average about 10. Remember not much work is being done here just keeping tension on an itty bitty piece of wire.

7000 FPM is pretty quick. Like I said our fastest is 1500m/min which is close to 5000 fpm.

Send me a PM with your contact info, I'm pretty sure I know who you work for already but let me know for sure (I may need help at some point).

To the OP, I hope you follow our advice. Trying to sync these drives is a waste of time, money, and hair.

 

[rdrast]

Finally!
The dancer is there for 2 main reasons. Tension, to keep the wire taught on the capstans, and speed feedback. Our dancers uses a 10 turn 10K high accuracy potientometer on the back of the dancer for the speed feedback. The speed feedback is fed directly to our siemens drives.

I think you mean Position feedback, not speed!

We run up to 7000 fpm on our drawing machines here (rod breakdown machines). We've got two-stage drawboxes, with a 400HP for primary breakdown, and a 200HP for the multi-gauge sections. I don't recall the HP of the annealer drive motors, but it isn't very large. The spooler motors are 25HP, direct torque controlled from the Dancer PID loop (in the drives, yuck, but these are older lines).
We generally wind on 30" bobbins for both copper and aluminum.

As an aside, before I switched the spooler drives to direct torque control, the OEM had them running in speed mode. That caused clearing of the armature fuses here for years, and wild oscillations of the dancer (very poor control). The final suggested remedy from the drive manufacturer was to put in bigger motors and drives (75 to 100HP). We went to torque control, and eliminated all of the problems.

 

[rangerfreak]

I think you mean Position feedback, not speed!

Like I said, sometimes the ol' brain don't work so good.