Bifilar wire

[z.monkey]

Howdy,
I have done a lot of experimenting with bifilar wire.  It works best on a low permeability core.  This is because the windings are aiding the electron spin in their neighboring windings.  This decreases the need for a "hard" high permeability core to produce inductance.  Having an iron core with bifilar windings is counter productive because the windings are aiding the electron spin in their neighboring windings the wires influence on the core is bucking every other winding.  Wind a regular core with all the windings in one direction, hook it up to your pulse generator, and "feel" the inductance of the coil by holding a magnet in your hand in close proximity to the core.  If you don't have a gauss meter, this is the second best way to judge the inductance.  Next wind up a bifilar core, and give it the same test.  You can even wire the two coils in parallel and "feel" them both in real time to make a judgment.

I have never seen magnet wire sold in a bifilar configuration.  What I have done in this situation is drill two tiny holes in the base of one of the ends of the core end.  Run two pieces of magnet wire through the holes and secure them, solder them together.  Then wind the two pieces of wire down the core in parallel.  The next layer gets way more complicated, the #1 wire of layer 2 needs to be ran directly on top of the #2 wire of layer 1, and the #2 wire of layer 2 needs to be ran directly on top the #1 wire of layer 1.  This is really hard to do.  I have not found an automated way to do it.  And, I don't think that it is really worth it in a "hard", high permeability core, because the core is canceling the gain produced by the bifilar windings.

Draw yourself a diagram of a core from the side view.  Then draw some little circles sitting on it which represent the wires in a cross section.  In a normal winding the electron spin is the same for every wire.  In a bifilar coil the electron spin of each wire is opposite on every other wire.  Draw some little circular arrows on the wires to represent electron spin.  Now in the normal coil the electron spin in influencing the core in the same direction.  In the bifilar core the electron spin influence on the core is broken every two windings.  This effect mitigates the gain of the electrons spin aiding created by the bifilar windings.

There is another way to wind the coil also.  Lay down one layer of wire in a clockwise direction.  Make two holes large enough to accommodate the wire, and have the first winding exit the spool, and the reenter the spool immediately.  Make the second layer of windings counterclockwise nested in the groove of the first layer of windings.  At the end of the second layer make another two holes in the spool, and wind the third layer clockwise.  Continue this process until you have the number of layers that you want.  This type of winding is a hybrid of normal windings and bifilar windings, but is compatible with a "hard" high permeability core because all the windings are in the same direction on each layer.  This way you don't get the electron spin bucking on the core, but you also get some of the electron spin aiding between the layers.  Am I including some of my notes from when I first started toying with the idea of electron spin aiding and bucking.

Happy winding...

[z.monkey]

Here is the second page of notes...

[prometei]

hey z.monkey thanks for posting your notes, unfortunately the scans are at very low resolution and I could not read everything more so print it out, could you scan them at a higher resolution?

I have never seen magnet wire sold in a bifilar configuration. 
........

The next layer gets way more complicated, the #1 wire of layer 2 needs to be ran directly on top of the #2 wire of layer 1, and the #2 wire of layer 2 needs to be ran directly on top the #1 wire of layer 1.  This is really hard to do.  I have not found an automated way to do it.  And, I don't think that it is really worth it in a "hard", high permeability core, because the core is canceling the gain produced by the bifilar windings.

The page I've mentioned in the first post http://wires.co.uk/acatalog/cu_enam.html has this description
"Bonded Bifilar Wire
Twin solderable enamelled copper wire in different colours parallel bonded."

So with this wire it would be easier to wind the coils the way you are describing.


One more thing. I'm not sure I understood the whole thing about the electron spin, how do electrons spin in a regular coil?



Which one is correct 1 or 2 or......?

[z.monkey]

Howdy Prometei,
Yes I can scan those at a higher resolution, but I can't post them on the forum, there is a 50K limit on attachments.  I could send them to your email address.  The bonded bifilar wire may be the right thing, the wires should run parallel all the way, not twisted.  I would need to see a picture, the website didn't have a picture.  It did say parallel bonded.  Yes this would make winding easier, but its not two hard to do with two regular wires.  Picture #1 is regular windings.  Picture 2 is bifilar windings, except that you should use a unique color to differentiate each wire of the bifilar pair.  Electron spin refers to the electrons spinning around a wire as they travel down the wire.  The electron itself spins as it travels through space leaving a wake in the ethers as it travels.  When the electron is traveling down the wire its own spin will cause it to travel in loops around the wire as it travels.  This is where the adjacent wires in the coil will either aid or buck the electron spin in the wire we are looking at.  The bifilar solution aids the electron spin in the windings, but causes bucking in core.  The type of hybrid winding described in my notes will improve the bucking in the windings, and also eliminate the bucking in the core.  Regular windings (all in the same direction) are "core oriented" windings that maximize the magnetization of the core and ignore the bucking in the windings.

If you want, you can send me your email address in a personal message (so as not to post it in public).  Then I can send you the enhanced resolution notes about the electron spin aiding and bucking within the windings.

Blessed Be Brother...

[prometei]

hey z.monkey

I've sent you a private msg with my email

I was also wondering what if one was to wind a bifilar coil using guitar string wire? You know the heavier gauge guitar strings consist of a core and a wire wound around it. So if one makes a coil using such wire one will get a coil wrapped around a coil I don't know whether or not this would be beneficial, just thought about it

When you say bifilar coil do you mean the bedini ssg setup or a coil where two of the four wires are joined at the end, like this