View Full Version : Coil Winding

10-06-2007, 07:11 AM
I just got my wire today, however due to the price of it, I'm a bit leery of just jumping into winding a coil with it. I plan on starting with one of the patents in Beardens book.

I have a few questions for those of you who have wound a few to start with.

1. About how tight should the twist of the wire be?

2. Is there a way to get exactly the right length before twisting? (as to not waste any of the wire, I'll have to spool the wire onto seperate spools to twist it.)

3. In Bearden's book, the coil is 450 turns, #23 wire, trifilar wound, I know in other circuits there is always a combination of #23 and #26 wire wound. Is this important or can the coil still be wound with 3 strands of the same gauge? (I don't have any 26 at the moment)

4 Also, I might have enough to go quadfilar or even quintfilar.. If I wind extra strands to use later, will that effect the circuit at all?

5. Any other suggestions are appreciated!

10-06-2007, 10:39 AM
1. For a beginner coil you do not need to twist the wires, the coil will work well also without the twisting. But if you want, you can twist it. The tighter the better. I would recommend about 1 twist per inch, that should do good.
2. I usually take my wires outdoors and wind them out till I have the wire of desired length. Then I add some more strands of wire to get the count I need for bifilar or trifilar coil . Then I simply attach one end of the strands to something and fasten the other end to a electric screwdriver and start twisting :)
3. You can wind all the strands with the same wire gauge, that will work fine and will be easier to twist than if using two seperate wire gauges.
4. Extra winds will not affect the circuit and you can use them later as slave coils with a separate transistor for each coil, or you may use two or three strands in parallel for powering to get less resistance and thus a little more power.

10-08-2007, 12:45 AM
Thanks for the advice.. I'm making my spools out of PVC and old cd's at the moment.

What I'm really hoping to do is to have as little waste as possible. The expense of the wire wasn't a small one and I'd hate to have lengths too short to wind other coils with. I have other projects I want to do as well after I wind this coil.

I'm sure over time I'll be getting more wire, especially if I want to scale up or down for different projects.

From what I've read, there are between 100 and 250 feet worth of wire for 450 turns. What I'd like is to have an exact way to calculate the length (with the consideration of the final twisted strand) at 450 turns. Maybe I can get close without going over and save what little wire I was able to afford. I'm sure there are a lot of considerations for this kind of calculation though.

10-08-2007, 10:29 AM
You can make the coil with more turns than 450. I have several coils, one is with about 600 turns, one with 450 turns and another one with about 800 turns and the all work well. :)

10-14-2007, 11:34 PM
Well, I figured out how to wind some spools so I can rewind them and twist them together.

I went for about 500 turns on each of them, but I have a sneaking suspicion that Its going to be a lot less when I finally wind them together.

We'll see.

Any way, as far as that goes, I figured I would also share some of the information I found on some things, such as creating a basic counter..

www.instructables.com/ low cost counter (http://www.instructables.com/id/Versatile-and-Low-Cost-Digital-Counter/)

This uses a calculator. It did work, but about half way through my calculator reset for some reason, I'm not sure why. I was having problems making up a decent contract that would activate on every rotation.

Currently I'm working on the next part, creating a twisting machine that can twist the wire as it advances the spool.

http://img98.imageshack.us/img98/3559/new2qj4.th.jpg (http://img98.imageshack.us/my.php?image=new2qj4.jpg)
http://img98.imageshack.us/img98/8210/new3ky0.th.jpg (http://img98.imageshack.us/my.php?image=new3ky0.jpg)
This is based on a design I've seen in the bedini sg yahoo group. I claim no rights to the initial idea.

A belt would go around the pulleys. The frame rotates while one pulley is stationary, attached to a base of some sort. The belt would advance the spool based on the ratio between the two pulleys. Now if I can just figure out how to pan the wire back and forth on the spool evenly...

10-20-2007, 03:32 AM
Producing wound components (http://info.ee.surrey.ac.uk/Workshop/advice/coils/)

This is an easy to follow, very informative, explanation. I had never understood the concept until I read this......

Hope this helps!

10-20-2007, 07:02 AM
Thanks for the link, I was actualy going to go looking for something like this after a bit so I can understand how to make coils. I have other projects I want to do that require smaller coils so I need to know how to figure this stuff out.:notworthy:

10-29-2007, 12:50 AM
Well, after 3 weeks of building the twister, I finally got to twist my first spool.

I wound about 500 turns on the 4 seperate spools and ended up with about 400 turns on the final spool, about 50 less than my target *sigh*

However, I was using 3/4 in PVC to make my spools, the OD on those is roughly 15/16 and the ID is closer to 7/8

I may be able to wind it onto a smaller spool to get the total windings up to 450 if I use a smaller diameter PVC. Sadly that will have to wait till next weekend when I can make another spool.

I'll also be able to use smaller diameter welding wire for the core, so I'll be able to stuff more into a smaller space so it won't reach saturation (still not sure how this particular aspect effects the coil's resonance)

10-29-2007, 12:54 AM
can you post some pictures?

10-29-2007, 02:04 AM
can you post some pictures?

Of which, the spools or the twister?

10-29-2007, 04:02 AM
I'm interested in the twister pictures since I'd like to build some contraption for myself as well, though I had a different idea from what you have posted (renditions above)...

10-29-2007, 10:20 AM
Of which, the spools or the twister?
I meant pictures of the twister :)
But some pictures of the spool would also be nice.

Ted Ewert
10-29-2007, 02:18 PM
I found an easy way to wind and twist multi filer coils.
I put spools of whatever type and number of strands I want on some type of roller that allows me to freely roll off wire. This could be a pipe of some sort.
Once that is done, I secure the ends to the spool I'm using and pull out about 20 feet of wire.
I use a battery operated drill, with the spool attached to the chuck, to start twisting the wire. This is done by running the wires through a small notch on the rim of the spool, then turning the drill towards the rolls of wire. (Make sure you secure the wires at the other end, where they are being rolled off, otherwise it doesn't work so well.) Start the drill twisting the wires until you are satisfied with the amount of twist. Then turn the drill 90 degrees, unhook the wire from the notch, and start winding the coil..
When the unwound strands reach your coil, put a little piece of tape across the windings so they don't uncoil, run the wires through your notch again and start twisting another 20 feet or so.
Keep doing this until you have filled the coil up. Then all that's left is to fill the core with iron.
Here is a simple little adapter I made that fits all my empty cores. I just tighten the cones into the core and it becomes a self centering drill attachment.


10-29-2007, 07:25 PM
Sadly I can't find my camera right now.

And besides that, I wasn't able to incorperate the self winding feature that I had designed, so it was all manual. It almost seems to me it would be easier to do with electronics and motors than a pulley system.

I also wanted to design a traversing system to wind the spools evenly. The hard part of all of this is figuring out how to do it without going custom (IE parts you have to make yourself that are too complicated) so that any one can build one.

Ted, I used an axle much like what you have, only I used rubber stoppers instead. It worked out pretty well, and I used a drill to wind my four individual spools to start with.

10-29-2007, 07:35 PM
I would consider using stepper motors to make a selftwisting setup. You will need two motors, one for winding and other for twisting. Controling these stepper motors is very easy and you can adjust different RPMs to each motor to get the twist you need. I am considering to build such a device myself since I have gained experience with steppers when I built my selfmade cnc router.