Maker Pro
Maker Pro

Stiff Wire and Tight Toroids

R

Robert Baer

Jan 1, 1970
0
D said:
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
Just get some #32 "magnet" wire and use ?20 to ?50 of them together
as a winding group...
 
R

Robert Baer

Jan 1, 1970
0
D said:
Would those wires need twisting?

I'm not sure but I think twisted wire occupies more cross section area
than untwisted.
How about no twisting?
D from BC
Leave Chubby Checkers out of this!
 
T

Tim Shoppa

Jan 1, 1970
0
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?

Large toroidal coils often use rectangular cross-section bar for
winding.

Not only does this facilitate the bending necessary during winding, it
also gives you more efficient packing of copper than plain-old round
wires :).

Typical for the large units I'm used to, the conductors might be a
quarter inch thick and an inch or two wide. Oh, yeah, and you can
stand inside the toroid during much of the winding process, you'd be
surprised how much easier this makes winding!

For even higher current capacity, copper tubing is often used and
chilled water pumped through the conductors.

Tim.
 
D

D from BC

Jan 1, 1970
0
Large toroidal coils often use rectangular cross-section bar for
winding.

Not only does this facilitate the bending necessary during winding, it
also gives you more efficient packing of copper than plain-old round
wires :).

Typical for the large units I'm used to, the conductors might be a
quarter inch thick and an inch or two wide. Oh, yeah, and you can
stand inside the toroid during much of the winding process, you'd be
surprised how much easier this makes winding!

For even higher current capacity, copper tubing is often used and
chilled water pumped through the conductors.

Tim.

Maybe I could get laminated flat wire? Probably a PITA to get item..

ooooo ...That's cool! :)
Conducting copper tubes with liquid inside zooming around a toroid.
D from BC
 
T

Tim Shoppa

Jan 1, 1970
0
Maybe I could get laminated flat wire? Probably a PITA to get item..

Not so hard... Google for "Laminax", there are places that sell it on
the net. There are other brands but I just happened to have the Alpha-
Core catalog on my desk! Also (IIRC) available with two parallel
conductors for bifiliar-type applications.

Alphacore also has toroid winding machines... and audio-fool class
cables...

Tim.
 
J

Joerg

Jan 1, 1970
0
D said:
D from BC wrote:

[snip]
I'll need a thin insulator around the stranded wire..
Seems like one of those PITA items to find.


Thin but lots of breakdown voltage? Check this company out:
http://www.rubadue.com/products.html

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.


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...

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:
http://www.rubadue.com/pdf/part_number.pdf

"L" under conductor material is for litz wire.

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..


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

john jardine

Jan 1, 1970
0
Robert Baer said:
Better yet, "pseudo-litz" by using a number of small (insulated)
wires in a bundle.
That way, less space gets wasted during winding due to the smaller
size as well as thinner insulation (use "enamel" instead of plastic).

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

Rich Grise

Jan 1, 1970
0
Does my post title seem a little perverted? :)

You wish. ;-)
I'd like to lower the copper loss in an inductor design.

OK, go ahead. :)
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?

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
 
D

D from BC

Jan 1, 1970
0
D from BC wrote:
[snip]
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..


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

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
 
D

D from BC

Jan 1, 1970
0
On 3 Apr 2007 09:12:55 -0700, "Tim Shoppa" <[email protected]>
wrote:

[snip]
Not so hard... Google for "Laminax", there are places that sell it on
the net. There are other brands but I just happened to have the Alpha-
Core catalog on my desk! Also (IIRC) available with two parallel
conductors for bifiliar-type applications.

Alphacore also has toroid winding machines... and audio-fool class
cables...

Tim.

Found it:
http://www.alphacoredirect.com/index.html?lang=en-us&target=d4.html
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:
http://www.dartmouth.edu/~sullivan/litzwire/skin.html
"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
 
D

D from BC

Jan 1, 1970
0
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

Yeah..but it's just cruel to let people over and over again play
around with all different wire gauges.
Generation after generation always thinking about the same wire
problem.
I think this is an experience item and I thought it might be difficult
to find with a Google search.
It's why I thought it would be best on usenet..
If the experienced take the knowledge to the grave,the next generation
won't get too far ahead..
"It's grandpa's fault things are so messed up!" :)
D from BC
 
J

Joerg

Jan 1, 1970
0
D said:
D from BC wrote:

[snip]
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..


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


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.


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

Robert Baer

Jan 1, 1970
0
Joerg said:
D said:
D from BC wrote:

[snip]

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..



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



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.



Stranded would be ok here I guess. But sometimes litz wire just happens
to be in stock.
But Litz wier is a bit spendy...
 
J

jasen

Jan 1, 1970
0
The trick to twisting wires is to spin the individual
strands and let then rotate around each other. The Boy
Scouts showed me the tool, made of two pieces of plank and 3
bent sections of coat hanger wire, that they use to make
rope, this way, from 3 strands of twine. But I have
approximated the effect by turning the three strands,
together, at one end, while letting the other ends rotate,
individually. But it is hard to keep much of a length from
tangling with three ends spinning around.

I used to twist cables by winding them backwards a few turns to pre-tension
them before combining them , I'd tie one end to a suitabkle anchor
(letterbox, doorknob etc) and hold the pre-tensioned wires in a clamp
(bench-vise, teeth etc) and do the twisting by hand or with a
hand-operated-drill with a hook in the chuck.

Bye.
Jasen
 
J

jasen

Jan 1, 1970
0
Thanks..
I'll be staying away from 16AWG or lower..
I imagined a nightmare project like winding a coat hanger on a toroid
:)

ooh,

I used coat-hanger wire to replace a broken spring in a door latch.
But that's steel and harder to bend than copper, IIRC from the last
time I locked my keys in the car...

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
 
T

Tim Williams

Jan 1, 1970
0
jasen said:
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).

http://webpages.charter.net/dawill/tmoranwms/Elec_Ind7_5.jpg

Much easier to cut and hammer the copper pipe flat when it's been red hot.
The extra 0.1% conductivity is just a bonus. ;-)

Tim
 
M

Michael A. Terrell

Jan 1, 1970
0
D said:
Does my post title seem a little perverted? :)


Actually, they sound like medical problems.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
 
M

Michael A. Terrell

Jan 1, 1970
0
D said:
For tight toroids try Preparation H. :p



Or a small grinder.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
 
Top