Thoughts / knowledge on toroidal coil winding

Apr 16, 2009 2 Replies

I've now tried both (hand winding) methods , hours and hours later decided some improvenment in technique is required if I ever try it again. Shuttle and loading ring methods . Loading ring is where you have a splittable ring. Shaped like a bike rim in commercial winders, I used soome polythene pipe , cut along one side, heated over a piece of dowel to form into a U section. Reform , taped, through the torus and wind the required wire while through the torus. Works but without a third hand or at least some sort of support for the loading ring it is awkward. Another problem with it, you need a way to hold the hank of wire on the ring without any of it coming off when the required wire is unloading. I just used a cylinder of rubber that just about held in place in the U, but has to be released every 5 or 6 turns. Some sort of foot controlled motorised system to wind back the excess wire onto the loading ring, for each manual pass of the loop through the torus, would help. The loading ring, permanently in the central torus hole, gets in the way of manually posistioning and tightening the turns.



Shuttle works quite well, but slowly, as I found you could only sensibly form at most 2 turns , then 2 combined shuttle passes. I've now tried some different ways to do say 10 shuttle passes and then return to manually tighten all 10 in one go. It requires a way of gripping the wire after each pass and then the next loading turn, staggered along some gripper thing that can be removed when returning to manually form the turns proper. With enough slack to grip and tighten but not so much as to knot-up. I tried Hellerman sleeving , pieces of rubber, slid along a tension spring. Held the ire well but difficult to remove the rack. Some rubber, sliced with 0.6mm grinding wheel , alright for larger diameter wire like 1mm or more and is easy to remove before manual stage. At the moment trying to track down some large hook Velcro to see if that would work. Anyone else been here before ?


-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Velcro would not work. Returning to the professional approach - the loading ring. Turning the whole thing through 90 degrees would make it much simpler. ex-VCR mode switch motor gearing driving a spool and 2 free-running ex-vcr spools on the inside of the polythene loading ring , fixed to the bench , rotating round in the horizontal plane. And toroid mounted vertically. So motor drive could be used to load up the wire initially and of course the main use, slack take-up, on each turn. If the circumference for a wiring turn is 150mm and the loading ring is 900 mm then to form one turn requires slipping 900 mm off the loading ring and taking up 750mm of slack each time, and shifting the anti-spillage bung every 6 turns.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Well the prototype bodged up loading ring system works upto 1.4mm diameter wire.

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Considering using a mode switch motor+ gearbox and spools from VCRs , bits of motorcycle inner tube, hosepipe, dictaphone footswitch and bits of Dexion etc. Only a test run so ignore the uneven layup. As long you start the retraction winding at the same time as slipping the large loop of wire, then no problem with turns of wire unravelling from the loading ring. I suppose its something you can get into the rythym of , once practised, as it is a continuous process. As it happens the retraction rotation speed was about right for a novice, 8 seconds for one rev of the 1 foot diameter loading ring. Loading up the ring intitially with wire, so running the motor continuously , did not even make the motor warm. With practise I suppose you could up the motor power and speed for faster actual coil wind. I would not fancy making the hook transfer system and tensioned forming system to fully automate.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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