@Localjoe,

Welcome back Joe, it's great to see you here with us once again, you have some of the best input I have seen, and thank you for starting this thread all the past years ago, and no doubt we will see more of it once again (like I just read top side).

@all,

I picked up a very old unusual A just a few days ago for $10 from a local farmer friend of mine, please see pics.

This coil is very unusual, where it is wound using FLAT copper which is COTTON covered.

It's contition is extreamly poor to say the least, and the cotton insulation is flaking off, so as it's condition is so bad, I will not attempt to power it up, but will dismantle it and take photos of this as I go.
This coil just may give us all some insights of the technology that was used back in Stubblefields days, which will be a bonus.

As I pull this coil apart, I will document it in fine detail (reverse engineer it) so we will have some idea how it was made.
Wire size, turns, insulation etc etc.

Here is the first of many photos I will post to keep us all up to date.

jim

2631 = Complete coil before dismantling begins, this is the back of the coil.
2632 = Close up of the FLAT copper turns, which are COTTON Insulated
2633 = Looking into the center of this huge coil
2634 = Front side of this coil showing the "TAP" points
2635 = Some of the muck on this coil, yuck.

@all,

The pull down continues with this "wonder" coil, I am learning "new" stuff at each time I take something further apart.

The BIG surprise so far is ALL the copper wires are SQUARE, they ALL are insulated in COTTON thread, and it looks like each layer is inter spaced by cotton sheeting just like a Stubblefield built coil.

The only difference I can tell is there is NO iron wire involved, just copper wires.
When I get further along with the dismantling of this coil I will let us all know if the primary is a single coil or a bifilar coil, but we gotta wait a bit first though.


jim

2636 = Very old nuts used to hold the iron core together, the center hole is out of round on all nuts
2637 = Top bracket of coil only is removed, so I can still keep the dismantle under control.
2638 = All the inter leaf irons are removed, the Red Fiber Board insulation falls away revealing rusty iron
2640 = The inner coils can now be seen, still in place where it has been for so many unknown years (75-100)
2641 = The copper core is being carefully removed, it is half way out of the inner iron core, BIG surprise to follow.

2642 = Copper "core" is now on it's own, BIG surprise here, as I placed it down, a part of the inner insulation fell away in a big chunk, it is COTTON woven sheet. NO doubt at this all, so here is proof that these big coils used COTTON insulation on the very first layor.

2643 = Another view of the above item

More to follow
 

@all,

Wonder Coil pull down continues.

2647 = These are the Primary windings for sure, no doubt as they are smaller in size to those wound on the outside of this coil. These inner copper wires definatly have cotton insulation on them, I will let us all know how many threads are wound around the copper wire soon enough.

2648 = The COTTON SHEETING, part only, the other part of it is still there, insulation inner barrier between the coil and the Iron former leaves, no doubt at all, I will take a look at all this with my USB Microscope shortly and post results, so much to do lol.

2649 = A downward looking view
2650 = Another downward looking view

2651 = This coil is just over 7 inches long.

jim

@all,

USB Microscope photos of this "wonder coil", leaving me NO doubt at all that cotton was used on the insulation of this coil, as the PRIMARY insulation.
This tells me this coil is very old, and for it to have survived in the condition it is in is simply amazing.

OK, the instrument I used to take the following photos is a ZOOM Digital Microscope which I picked up from Jaycar Electronics for $99 Australian in Toowoomba.
It comes with it's own installation CD, cable, booklet. I can Manually Zoom in or out, Manual Focus, can take a photo by pressing the top button or by clicking the mouse key, a nice little doover.

001 = Cotton weave patton in the cloth, taken from the "final" center layer of this coil
002 = A close up of the cotton cloth fibres
003 = Resin on this cotton cloth.

004 = The smaller "primary" turns of copper wire seperated by some unknown as yet insulation material
005 = A close up of this "unknown" insulation, it looks to me as though it could be a "fiber board"
006 = 1st copper layer showing the copper turns, 1st insulation around the copper wire and a bit of the inner cotton insulation barrier between the copper coils and the iron former
007 = Close up of cotton covered copper wire
010 = Thin Rope or thick string, could be hemp, which bound the last cotton sheet layer around this coil
011 = Cotton covered "wider secondary coils"
012 = close up of these cotton fibers, not many on this section.


 
   

Nice find. The 4th photo down looks like pvc insulated wire?
It appears to me like an old transformer.