A couple coil experiments What do you guys think?

[godigit1]

What I've done is take the 3D SS wind and placed it in either a flat or vertical stack. You will recognize the patterns but any shape can be used.

The first was a flat stack and done on a dart board.



It is a attempt at a self shielding solution in that I took enough wire for five wraps and placed it on the form before starting the wraps.
After 25 wraps i brought it over the top and wrapped the last 5 wraps backwards on the form. (Actually keeping the winds in the same direction.)

Here it is with the first 5 wraps so you can see how it winds up. on the next 5 you jump forward to the next row of tooth picks and go the next 5. Then alternate back and forth.



Here it is finished with 30 wraps 26 awg tinned 7 stranded wire . Not the best wire to use I know.
I'm using foam to lock them all together. When its cured you just pull the tooth picks and trim it to shape.




This coil turned out slightly below average on depth but is quieter in my bad test environment.
What do you guys think of the last 5 wraps being brought from the bottom of the coil?
I was thinking if connected to the ground it would shield the coil because the positive is sandwiched.

This one is a 8 "round coil pattern using a phone book sandwiched between two pieces of wood and then cut out with a jig saw for the mandrel.
Here is the form and a coil that just came off.



In the following pictures you can see how the pattern really stacks up and how much air space there is between wraps. Also notice the corners how they alternate instead of stack over each other as on the 3DSS form with tight pinched direct stacks.
I think that maybe this coil may have some benefits there.
I'm not sure about the self shielding aspect any more though?
I have not tested the yellow one yet 26 awg solid 30 wraps 319uh 2.9 ohms . But the purple one 24 awg solid 30 wraps 310uH 1.9 ohm works very well ,its not sensitive to hands or movement performs really good on the barracuda, the fly back is clean and gone in 3us if thats any way to measure how fast it is. . I've not tested it yet on the minipulse or the tdi but Ill let you guys know how that goes.









Any advice in helping to modify the design such as optimum width spacing so on would be greatly appreciated. Or if its a waste of time?

Thanks

[Qiaozhi]

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[6666]

Would like to see your pictures.

[godigit1]

Sorry guys they worked when I previewed the post. Ill try again.
First coil with the flat layup.

Here it is at 5 wraps.

Here are the two finished shots.

Here is the 8 inch coil and form.
.
And here are the close ups of the wind on the 8 inch coils.
Ok looks like there working now.
Thanks For the heads up.

[Koala]

Lot of hard work there. Well done. Wait to see how they preform.

[baum7154]

Beautiful craftsmanship in the construction!
Sorry to say that these coils are not 3DSS and if I understand the geometry are really 'stacked' 2 Dimensional coil windings. The reason is that successive windings are not wrapped 'around' all previous windings as in 3DSS, but are simply layed down as the next 2 dimensional layer or rather, spiral. These coils will not self shield because either the 'hot' end is on the bottom layer or it is on the top layer and is not surrounded by shield at ground. On the 3DSS the hot end is placed on the inside winding start with the ground on the outside winding end. Hope this helps.

Dan

[Davor]

Funny thing is that I made a coil for testing purposes in a similar fashion like the edge-wound one, and I only did it this way half way through to provide some rigidity to the spokes, released the half-made coil from a former together with spokes, and wound the rest of the coil around in a 3DSS style. Oh, and one more detail, mine is ugly. But there is no former inside my coil, and spokes are also optional.

Edit:
My point was actually that such a beautiful coil may be wound to, say 100uH, this beautiful way, and wrap-wound finished in a 3Dss style. Because there is no former inside, it may be incredibly lightweight and fast, and self-shielded as well.

[baum7154]

Hi Davor,
An interesting adaptation of the 3DSS geometry and principal.
I can see where that is possible assuming the last winds are made in the same direction as the core was wound.

Regards,

Dan

[WM6]

Funny thing is that I made a coil for testing purposes in a similar fashion like the edge-wound one, and I only did it this way half way through to provide some rigidity to the spokes, released the half-made coil from a former together with spokes, and wound the rest of the coil around in a 3DSS style. Oh, and one more detail, mine is ugly. But there is no former inside my coil, and spokes are also optional.

Edit:
My point was actually that such a beautiful coil may be wound to, say 100uH, this beautiful way, and wrap-wound finished in a 3Dss style. Because there is no former inside, it may be incredibly lightweight and fast, and self-shielded as well.

Posted such idea design month ago on another forum:

http://australianelectronicgoldprosp...9100/#msg39100

[Davor]

Mine is a basket inside, and 3DSS outside. But you put some interesting plastic profile for stem connection - what is it?

[godigit1]

Hi guys Thanks for the positive comments.

Hi Davor
I can try a coil that way and do say maybe the first 25 wraps on the form, foam it then remove it and trim it to size and do the final 5 wraps on a second form extended out where i can get behind it and do a Standard 3D SS shield around it lock it in with foam and remove the toothpicks
or nails at that point re trim it and it would still be formless.
I think I will start one tonight if I get off early enough.

Hi Dan,
On the first example I have the wrap where negative is on both sides of the coil and winds toward the center. maybe doing this method and putting the Positive lead directly in the center may be better instead of under only five wraps. What do you think maybe a shielding ???

I have Graphite shielding and will also make a shielded housing to see if I loose performance.

I would be willing to make and send someone better capable than myself a coil for proper full testing As well as one with 23 wraps for Green to add to your chart if your out there and interested.
Of coarse you could keep them when done.

Thanks Again for all your help.
Digit

[WM6]

Mine is zig-zag (somewhat "basket"-like) wound inside (zig-zag wound turns inside, act as coil former for final two way /sparsely/ wound spiral self shielding turns).

"Plastic profile" to holding lower rod are in fact impregnated wooden Chinese chopsticks ("Lidl" surplus) finally epoxied and painted.

[baum7154]

Hi guys Thanks for the positive comments.
Hi Dan,
On the first example I have the wrap where negative is on both sides of the coil and winds toward the center. maybe doing this method and putting the Positive lead directly in the center may be better instead of under only five wraps. What do you think maybe a shielding ???

I have Graphite shielding and will also make a shielded housing to see if I loose performance.

I would be willing to make and send someone better capable than myself a coil for proper full testing As well as one with 23 wraps for Green to add to your chart if your out there and interested.
Of coarse you could keep them when done.

Thanks Again for all your help.
Digit

---------------------------------------------

I think if you are not encircling the coil windings with the ground end of the winding, much like winding a toroid core, the self shielding won't be effective. The other thing to remember is to keep the width of the coil bundle compact so as not to spread out the shield over too great of an area leaving bigger holes in it. In other words I think a compact, nearly circular cross section of the air spaced coil is best. I try to keep my 3DSS coils within about 1.1" cross section.

Regarding graphite shielding I do have a 3DSS coil wound with enamel sold wire that is also graphite shielded at about 1300 to 1500 ohms /inch and it suffers from loss of speed and sensitivity. Probably the fault of the solid enamel wire. I would not graphite shield the 3DSS coil unless it is absolutely necessary...try it out first.

Dan

[godigit1]

Hi Dan,
I should have included the bundle size before the 24 awg coil with 30 wraps is 3/4" high by 5/8. the 26 awg is 3/4 high by 1/2 wide.

Since lunch I have had some time to think about it and I have a way to easily form both coils together.
Ill go my wind for a air core and 3D SS wrap to top it off as suggested .
I have got some more of the 26 awg on hand so Ill use that for starters.
Give me a little time to put it all together should be fun.

Thanks again everyone.

[Davor]

Mine is zig-zag (somewhat "basket"-like) wound inside (zig-zag wound turns inside, act as coil former for final two way /sparsely/ wound spiral self shielding turns).

"Plastic profile" to holding lower rod are in fact impregnated wooden Chinese chopsticks ("Lidl" surplus) finally epoxied and painted.

I'm interested in this particular plastic thing: