I think you are saying that the wire is wound on the larger tube sort of like thread is wound on its spool. That makes for a larger OD and so might not be able to pass thru the toroid hole. I have some toroid transformers about 1/4 inch OD with hole of about
3/32 inches; as a guess, #24 wire was used to wind them. The wire size certainly reduces the space available for any kind of shuttle by a goodly factor. Hence that is why i mentioned the use of a needle or doing the winding by hand.
telescopic radio antennas are another source actually for this task you could probably just use a soda straw and bamboo skewer,
On Sat, 30 Dec 2006 03:47:27 GMT, ehsjr Gave us:
The "hand tool" for winding toroids is your hand, and what is called a push stick. Each core size has its own sized push stick. It must pass through the core while also having clearance for several layers of wire on EACH side . The ends of the stick has a small notch in it to allow control of the wire as it is being fed through. The finished product looks like a ruler that has been carved into an elongated, narrow dog-bone shape. Wood works, but teflon or other non abrasive plastic is good too. Nothing hard or metallic as damage to the varnish on the mag wire is possible.
Otherwise, it is a fairly complex textile industry like piece of machinery if you want it automated. Or maybe wire/rope industry like...
On Sat, 30 Dec 2006 07:42:17 GMT, Robert Baer Gave us:
Ah... My first response regarded fairly large toroid coils. It appears here that you are speaking of tiny form factors.
Yes, hand winding is the easiest, and if one really want ease of wind as well as high performance, use a Litz wire that has the equiv. size as the solid you were considering. It is easier to wind and usually performs better on this tiny stuff. I even used it as my main primary winding media for my tiny HV switchers. It outperforms solid wire at switcher cycle rates by far. Worth the extra price if one wants to maximize the efficiency of a design involving magnetics at high frequencies.
Yes it's like that. Except a sewing spool is short and stubby, and the thread is wound in a lot of layers. The shuttle is long and slender by comparison, and wound with only the amount of wire needed to wind your toroid, so you keep the layers on the shuttle to a minimum.
Yes. You must use the size of brass tubing that will fit through the toroid easily when the tubing is wound with wire.
Obviously there will be times when it is better to do it with no tools, or with a larger wooden (or plastic) "conventional" toroid winding shuttle when the inner diameter is large enough.
The point is that the shuttle described can be smaller than the "conventional" wooden kind with the notch in its ends. For toroids smaller than the smallest shuttle you can make, your sewing needle idea is good.
Ed
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