What is it about coil winding automation projects that’s just so captivating? Maybe it’s knowing what a labor saver they can be once you’ve got a few manually wound coils under your belt. Or perhaps it’s just the generally satisfying nature of any machine that does an exacting task smoothly and precisely. Whatever it is, this automatic Tesla coil winder has it in abundance.
According to [aa-epilectrik]’s account, the back story of this build is that while musical Tesla coils are a big part of the performance of musical group ArcAttack, they’re also cool enough in their own right to offer DIY kits for sale. This rig takes on the job of producing the coils, which at least takes some of the drudgery out of the build. There’s no build log, but there are enough details on reddit and Instagram to work out the basics. The main spindle is driven by a gearmotor while the winding carriage translates along a linear slide thanks to a stepper-driven lead screw. The spool holding the fine magnet wire needs to hold proper tension to prevent tangling; this is achieved through by applying some torque to the spool with a small DC motor.
There are some great design elements in this one, not least being the way tension is controlled by measuring the movement of an idler pulley using a linear pot. At top speed, the machine looks like it complete a coil in just about three minutes, which seems pretty reasonable with such neat results. Another interesting point: ArcAttack numbers [Anouk Wipprecht], whom we’ve featured a couple of times on these pages, among its collaborators. Small world.
Certainly looks easier than sitting in a cold shed winding one with a mate on a metal lathe – both hindered by prior consumption of rum.
Clearly you have more fun winding them though.
Coil winders seem to be relatively popular. Maybe a Hackaday article every year or so?
I don’t make enough coils to make a full blown gadget for it.
Mike Harisson has made a simple setup for some coils: https://www.youtube.com/watch?v=yeEbZzjFgvE
Another hack would be to use a small DC motor and a Lab Power supply in constant current mode.
With CC mode you have a constant torque for a DC motor and this results in constant tension in the wire. Then you can simply feed in as much wire as needed manually, or apply some friction to a spool of wire to control unwind speed.
Next step up is of course to add a turn counter. Either via a simple magnet as in Mike’s first attempt, or with an encoder.
My father made one powered by a sewing machine motor, controlled by the sewing machine’s foot control. It worked quite well, if I remember correctly.
I did something similar a lot of years ago, winding sapphire fiber on a large spool. The short (100 ft)lengths of fiber were fusion welded to make longer lengths. I used a follower arm on a pot to control the DC voltage to an ordinary shaded pole motor to control tension. Absolutely smooth magnetic drag. An LM317 regulator was all I needed for the variable voltage. Most people don’t believe this, but easy to test. Pitch control with a stepper motor driving a lead screw. Each layer protected with paper so the fiber wouldn’t scratch and weaken the strength of the fiber. The fiber was used to make ceramic composite parts for rocket motors. Strong and not brittle.
A shaded pole motor is an AC induction motor, how did you drive that with DC? Or did you just use it as an eddy current brake? That’s a nice idea.
This unit uses a PID loop + a spring force term to regulate tension. We found with a fresh copper spool, the centrifugal force was enough to produce more drag than desired at high despooling speeds. So depending on the conditions, the loop will add drag if it needs to or assist in despooling. Was a fun problem to solve!
Cool video. I have been pondering a coil winder for a while. When it was first started I was thinking gee, that is not super fast, but it cranked up quite well. Neat project.
I once made a diy Coil-Winder out of an old Sheet printer mechanism.
Worked very well too!
I made one for winding Rogowski coils on a coax former from an old inkjet and LinuxCNC. Very easy to make as the steppers were already there doing the right things though it was never fast.
My first winder used a speed controller on a 1952 era Delta wood lathe. It worked quite well. The second time around I built two independent end units, one having a hand crank and the other having a mount for a cordless drill. That one was far better in terms of speed control.