Stiff Wire and Tight Toroids

Does my post title seem a little perverted? :) .....anyways.. I'd like to lower the copper loss in an inductor design. So, I'm lowering the wire gauge to reduce the resistance. However... (I never get something for nothing in electronics.. :) Aside from running out of room for turns, could the wire be too stiff to wind?

Some core info:

100 turns Across: 1.1cm^2 OD: 1.6"

At what gauge does it generally get too difficult to hand wind a tightly wound toroid??

What's the gauge of the fattest wire that can be found in typical switchmode power supply magnetics?

What's the gauge limit on a typical toroid winding machine? D from BC

Reply to
D from BC
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Wow! Particle accelerator???

I'll need a thin insulator around the stranded wire.. Seems like one of those PITA items to find. D from BC

Reply to
D from BC

On Mon, 02 Apr 2007 17:56:45 -0700, Joerg Gave us:

Depends on the hole size, and the wire type. Solid mag wire gets pretty stiff below 16 Ga. (relatively). Fingers get sore fairly quickly if large quantities of finished product is needed, and uniformity is retained throughout.

Depends on the number of turns you need.

Depends on the turns needed, and the fact that final operating temperature must be controlled.

The hole diameter is what matters for winding. Hand "winding machines" use a poke through dolly/caddy. It has to be very narrow if more than one layer of windings is required.

Reply to
MassiveProng

I.D. and wire gauge might be of interest as well. If its too small, large wire might not fit.

Use Chinese prison labor.

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Paul Hovnanian     mailto:Paul@Hovnanian.com
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Have gnu, will travel.
Reply to
Paul Hovnanian P.E.

When them fingers still hurt the next morning despite a good dose of aloe vera?

I have seen up to garden hose diameter. The drums came in via a railroad connector line and were unloaded by a huge crane.

Don't know the machine limits versus core diameter but why don't you use stranded wire?

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Regards, Joerg

http://www.analogconsultants.com
Reply to
Joerg

Nope. IIRC it was for locomotives for a Brazilian railroad.

Thin but lots of breakdown voltage? Check this company out:

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A client uses their litz wire and I had to make some experimental pulse transformers with it. Very smooth. No cracked nails and not a single callus at the end of the week.

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Regards, Joerg

http://www.analogconsultants.com
Reply to
Joerg

My personal limit is around 16g, and I'm not even sure I'd want to wind 100 turns with that. A 1-off might be OK, but not 10 !!

They can go a lot thicker, but Litz wire is more normal.

Barry

Reply to
Barry Lennox

Would that make it a SMPA? (c:

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John English
Reply to
John E.

[snip]

Cool ...thin insulation... I couldn't find the Litz wire on the site.. Nor did I see: "To order trainload of Litz wire...press here.." I'll poke at the site again later...

By the way...I mentioned a thin insulator covering the stranded wire (bare stranded wire,not Litzy) to take up less space. I was comparing to plastic coated stranded hook up wire.

My app has negligible losses due to skin effect. Mostly core and copper loss. Kinda ironic to use Litz wire to control copper loss due to low guage wire being too stiff.. D from BC

Reply to
D from BC

There's something you won't see on Ebay... D from BC

Reply to
D from BC

I knew a guy who wound solid #8 on toroids. He built a machine with a flat steel-plate table with a hole in the middle. There was a sort of huge crochet hook that came through the hole from below, through the toroid, and hooked the wire. Then the operator hit a foot pedal and a pneumatic cylinder pulled the hook down, doing the tough part of the winding. The rest of each turn was pretty much manual labor.

John

Reply to
John Larkin

Thanks.. I'll be staying away from 16AWG or lower.. I imagined a nightmare project like winding a coat hanger on a toroid :) But that's steel and harder to bend than copper, IIRC from the last time I locked my keys in the car... D from BC

Reply to
D from BC

The web site is, ahem, maybe not one of the best. Give them a ring to see what's in stock. This shows how their P/Ns are structured:

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"L" under conductor material is for litz wire.

Not ironic at all. It's done all the time. Even electricians use stranded wire.

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Regards, Joerg

http://www.analogconsultants.com
Reply to
Joerg

The transformer guy calls it "rope" and doesn't like winding it :(. His rope works well so I just carry on speccing it.

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Reply to
john jardine

You wish. ;-)

OK, go ahead. :-)

Well, it depends on a whole bunch of other factors, (like, how stiff of a wire can you wind on a toroid with your bare hands?) which you should be out there researching instad of trying to swindle us into doing your homework for you.

Good Luck! Rich

Reply to
Rich Grise

[snip]

IIRC true Litz is woven like fabric... It's just ironic to use a metal fabric just for it's flexibility. It's primarily made as a solution to skin loss.. Stranded wire (bare) is flexible too and easy to come by... But true Litz...I still consider it a PITA to find item. D from BC

Reply to
D from BC
[snip]

Found it:

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I seeee shopping carts!!! That's a good sign.. :) So...I'll add it to the list....

So many choices for low DC conductivity and flexibility... Flat wire Thin insulated bundle of bare stranded wire Litz wire (woven) Pseudo litz (insulated strands)

The Litz is probably the most versatile in that any leftovers are also good for high frequency inductors.

Pseudo litz is good. I can get any DC conductivity by increasing strands. If needed, the strand gauge can be selected for low AC (skin) resistance.

Thin insulated bundle of bare stranded wire (like hook up wire) is something I have to Google up..This should be the least expensive.

Flat Wire Say I want #12 conductivity. Let's say it's too stiff to wind. Equivalent to #12 Alpha core flat wire has a 1:2 ratio ..(thickness:width) I'll guess it's like winding with ____ AWG. I couldn't find the wire height on the Alpha site!!!... ..math hurts... :(

Laminax Well..I wish there was some app notes on the Alpha Core site. Toroid pictures would be nice.. I might do a construction trial winding a strip of plastic on a toroid. Winding with a 0.5" strip on a 1" ID 1.3" OD toroid just doesn't seem physically right.. Also, I have to do the DC conductivity math for 0.01"x0.5" copper (per

1000ft)

I did some reading on:

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"proximity-effect losses typically dominate over skin-effect "

However my inductor design has a Idc^2 to Iac^2 ratio = 98@100khz... So that's why I'm favoring wire conductivity over wire structure. And also the proximity effect calculation looks painful.. :) D from BC

Reply to
D from BC

Stranded would be ok here I guess. But sometimes litz wire just happens to be in stock.

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Regards, Joerg

http://www.analogconsultants.com
Reply to
Joerg

But Litz wier is a bit spendy...

Reply to
Robert Baer

ooh, I used coat-hanger wire to replace a broken spring in a door latch.

much harder,

if you can find a way to enamel your own wires,

annealed copper is much more flexible than cold drawn copper (which most wire is) unfortunately annealing it will burn the insulation off (you need to get it red-hot).

Bye. Jasen

Reply to
jasen

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