Help winding my own inductor?

[John Popelish]

John Woodgate wrote:

John Fields wrote:

1000 times, no, John?

Z = n˛ through a transformer, but for an inductor, L changes linearly
with n.

Oh, no, John, no, John, no, John, no! Not if the turns are close-
coupled, as they are in a pot core.

How about if you adjust the gap to hold a constant flux for a given
current as you change the number of turns?

--
John Popelish

 

[Paul Burridge]

On Sun, 21 Dec 2003 21:37:39 GMT, John Popelish <jpopelish@rica.net>
wrote:

John Woodgate wrote:

John Fields wrote:

1000 times, no, John?

Z = n˛ through a transformer, but for an inductor, L changes linearly
with n.

Oh, no, John, no, John, no, John, no! Not if the turns are close-
coupled, as they are in a pot core.

How about if you adjust the gap to hold a constant flux for a given
current as you change the number of turns?

What is this "gap" to which everyone is referring? The spacing between
turns or something else?

--

"I expect history will be kind to me, since I intend to write it."
- Winston Churchill

 

[Winfield Hill]

DarkMatter wrote...

Winfield Hill wrote:

I'll
venture that most commercial litz wire isn't fully woven, but
it performs much better than simple twisted strands.

You lose. Most commercial litz is simple twisted or even non
twisted bundling.

I'd appreciate it if you didn't so severely truncate my posts,
and then respond to an incomplete "answer" that I didn't give.

In fact, unless the number of strands is very small (i.e. one
layer after twisting, which is rare for litz) simple twisting
does NOT suffice to make litz wire. I've spec'd, purchased
and measured different types of litz from wire manufacturers.
Their solution to an inability to make a genuine weave is to
twist a modestly-small number of strands, then use multiple
sets of these as fatter wires in a secondary twist, then twist
sets of these thicker ropes to make up a completed wire. The
goal of multiple-layer schemes should be to move each individual
strand of wire through as many of the available locations within
the completed "cable" as possible, in such a manner that would
approximate the result from a true weave. One cannot do this
with simple twisting.

It's not useful to characterize the result as "twisted wire," and
certainly not "simple twisted," as you asserted. Litz performs
decidedly better than conventional twisted wire, simple or not.

Sadly, many (if not most) modified-twist schemes in fact fail to
fully distribute each wire's pathway throughout the complete area,
which can lead to substantial litz performance failures, with the
high-frequency Rac/Rdc exceeding unity in multilayer inductors and
transformers. Dark Matter, many of the examples on the cover-page
of your web-page reference would perform poorly against a properly-
designed litz wire (I see a few good prospects there as well).

Finally, I know of no wire manufacturer who makes simple bundles
of multi-strand insulated wire and calls this "litz wire." None
of the manufacturers I've used offer such a "weave" option, and
I would not purchase such wire if they did, because it would not
succeed in solving common severe proximity-effect problems.

Thanks,
- Win

whill_at_picovolt-dot-com

 

[Ross Mac]

"John Fields" <jfields@austininstruments.com> wrote in message
news:qvtbuvs20qat9r585g3p1htjm0f4m5l6fp@4ax.com...

On Sun, 21 Dec 2003 10:16:27 -0800, DarkMatter
DarkMatter@thebarattheendoftheuniverse.org> wrote:

On Sun, 21 Dec 2003 17:09:03 +0000, John Woodgate
jmw@jmwa.demon.contraspam.yuk> Gave us:


'Litz' is short for the German word 'Litzendraht'. Being a German noun,
it starts with a capital letter. 'Litze' means 'lace', 'cord' or
'braid'. The strands of genuine Litz are interwoven in a specific way,
not just twisted or bunched.

Wrong. They MAY be woven, but generally are just twisted.

It works only for certain numbers of
strands, in the same way, roughly, as twisting works properly only for
7, 19, 37, 61, 97... etc. strands (numbers above 37 may be slightly
wrong).

Here you speak of perfect twisting. Which is it, boy, twisted or
woven?

No. TWISTING only works well with certain strand counts. You
describe circular object nesting numbers. A given, and known for
centuries. You state nothing new.

Litz effects occur with any count above one. It is simple math.
More skin, better performance. Period.

---
Litz effects???

--
John Fields

If I ever have to build a custom choke, I know who to send my first message
to!....You certainly have a lot of experience in magnetics, as do a couple
of others on this thread...Pretty informative stuff....thanks...Ross
(Too bad DM mucked up the thread!)

 

[Spehro Pefhany]

On Sun, 21 Dec 2003 23:00:27 +0000, the renowned Paul Burridge
<pb@osiris1.notthisbit.co.uk> wrote:

On Sun, 21 Dec 2003 21:37:39 GMT, John Popelish <jpopelish@rica.net
wrote:

John Woodgate wrote:

John Fields wrote:

1000 times, no, John?

Z = n˛ through a transformer, but for an inductor, L changes linearly
with n.

Oh, no, John, no, John, no, John, no! Not if the turns are close-
coupled, as they are in a pot core.

How about if you adjust the gap to hold a constant flux for a given
current as you change the number of turns?

What is this "gap" to which everyone is referring? The spacing between
turns or something else?

An air gap in the magnetic circuit.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Tim Auton]

Paul Burridge <pb@osiris1.notthisbit.co.uk> wrote:

On Sun, 21 Dec 2003 20:06:51 +0000, Tim Auton <tim.auton@uton.[group
sex without the y on the end]> wrote:

Please, move on to the 20th century (if you can't manage the 21st) and
use metres (mm in this case). This is the perfect example of why
metric is overwhelmingly superior to the array of units that
constitute that various imperial systems still in use in some parts of
the world.

They were nice when we had to do calculations in our heads. Those days
ended decades ago. Move on.

Screw the metric system. Long live Imperial measures!

What you gonna do? Liberate me?

I aint got no oil.


Tim, XX.
--
The .sig is dead.

 

[DarkMatter]

On Sun, 21 Dec 2003 12:56:16 -0600, John Fields
<jfields@austininstruments.com> Gave us:

On Sun, 21 Dec 2003 09:45:42 -0800, DarkMatter
DarkMatter@thebarattheendoftheuniverse.org> wrote:

On Sun, 21 Dec 2003 10:35:43 -0600, John Fields
jfields@austininstruments.com> Gave us:

--
What effect?

Now, it appears that you don't even know what litz wire is for.

---
No, just trying to see if you know what the Litz effect is.
---


I found a chart that lists litz configurations with strand counts as
low as three.

---
Not two, as you previously pontificated?

There is a difference between the clinical definition for the term,
nd the offering by wire makers. Nobody wants a two wire
configuration. That doesn't make it any less measurable in effect,
therefore valid to call litz.

 

[DarkMatter]

On Sun, 21 Dec 2003 13:00:10 -0600, John Fields
<jfields@austininstruments.com> Gave us:

On Sun, 21 Dec 2003 09:48:25 -0800, DarkMatter
DarkMatter@thebarattheendoftheuniverse.org> wrote:

On Sun, 21 Dec 2003 10:35:43 -0600, John Fields
jfields@austininstruments.com> Gave us:

But not because of the diminution of skin effect, unless you're talking
RF.


Skin effect is the exact reason. Again, I can place the same number
of turns at the SAME circular mil area onto a core and get different
performance at different operating frequencies, and said performance
is HIGHER on the multi-strand configurations, and the reason IS skin
effect.

Where have you been?

---
Watching you bury yourself.

I thought people only had two feet, but you seem to have a never-ending
supply of them you use to insert into your mouth.

Quoted from a reputable magnet wire maker:

"The multistrand configuration minimizes the power losses otherwise
encountered in a solid conductor due to the "skin effect", or the
tendency of radio frequency current to be concentrated at the surface
of the conductor."

Bury yourself in that, idiot.

 

[DarkMatter]

On Sun, 21 Dec 2003 13:11:29 -0600, John Fields
<jfields@austininstruments.com> Gave us:

If you think a Litz-wound choke has anything to do with better operation
of a linear supply because of skin effect then I suggest that the threat
to your livelihood which I pose, as you claimed in a previous post,
diminishes to zero when compared to the threat you pose to yourself.

You an idiot. We just made a big linear, and it operates at 19kHz.
Quite sufficient for skin effect to make a difference.

In fact, the solid wire choke made the unit fall out of spec on the
ripple figure of 10mV at 1500V out.

We don't make toys.

 

[Spehro Pefhany]

On Sun, 21 Dec 2003 08:22:14 +0000, the renowned John Woodgate
<jmw@jmwa.demon.contraspam.yuk> wrote:

Yes, it was too late at night, and after too many wine gums. TMESIS.

Mmmmm... Maynards.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[DarkMatter]

On Sun, 21 Dec 2003 13:30:56 -0600, John Fields
<jfields@austininstruments.com> Gave us:

OK, find me a reference to two-strand Litz wire and I'll believe you.

A few posts ago, you were telling me my seven strand wire was not a
litz wire.

Screw you. Anything over one strand is litz configured, because the
reason for doing it is to increase skin (overall surface)area.
I have seen two strands make measurable difference.


We have a miniature 1/4" x 3/4" x 1 1/4" HV transformer that will
not function in the circuit it goes into without a litz primary.

I made those proto transformers, and I made every configuration from
a solid wire up to pro grade HF litz wire.

Two strands makes a difference, but the transformer won't start
working right until at least five strands of primary wire are used.

It runs at 49kHz perfectly with litz wire.

The reason? Skin effect.

It will be a 50M piece order, so if solid wire could be used, it
would.

The term for today is "crest factor".

 

[John Popelish]

Paul Burridge wrote:

On Sun, 21 Dec 2003 21:37:39 GMT, John Popelish <jpopelish@rica.net
wrote:

How about if you adjust the gap to hold a constant flux for a given
current as you change the number of turns?

What is this "gap" to which everyone is referring? The spacing between
turns or something else?

It is the space between UU, EE, pot, PQ, RM or other two piece ferrite
or stacked laminated cores. The energy in inductors made with high
permeability material resides mostly in the field that passes through
the gap, as does the saturation resistance during high amp turns
operation. The core essentially couples the turns (carries most of
the same field around all the turns) and focuses it through the air
gap. If you design an inductor for some peak current and at the
current it reaches some specific flux, and you wish to change that
inductor to a higher inductance at the same current, you have to
increase the gap size, first, to keep the flux the same at the higher
amp turns. But increasing the gap lowers the AsubL value (inductance
per sqrt turn) so you also need more turns than what it would have
taken if the gap had not been enlarged. So under this constraint, the
inductance is no longer proportional to the turns squared.

A more useful constraint might be that the total amp turns remain
constant and the gap remains constant (also fixed peak flux) as you
change the inductance by filling the window to the same extent with
different wire sizes. Since the core geometry is constant,
inductance proportional to turns squared holds. But the current
capability goes down as the inductance goes up. Double the number of
turns, and the current capability goes down by half, while the
inductance goes up by a factor of 4. The resistance also goes up by a
factor of 4 (twice as long a wire with half the cross sectional area
for the same coil cross section). So the resistive losses at full
current stay the same.

Going through the range of inductances possible for a given pregapped
core using this rule shows the normal optimum use of the core as an
energy storage inductor. If your required product of square root of
inductance times current (which is essentially a constant for a fixed
gap and fill factor) is more than any example for a given gapped core,
you need a larger core. If your product is smaller, you are wasting a
bit of the core's capability (which you may want to do to lower
losses).

If you put a spacer between the halves of an ungapped core pair (or
add space to a pregapped set), you get a different product of square
root inductance times current for each gap, but there is a best gap
for any combination (from a total loss standpoint) for any combination
of DC and various frequencies of AC current. For large, high
frequency AC applications, larger gaps are better from a core los
standpoint because of the lower flux swings and the lower hysterisis
losses. For DC current, the core losses are zero, so the smaller gap
lowers the number of turns, allowing fatter copper and lower resistive
losses. You just have to worry about saturation and inductance
tolerance.
--
John Popelish

 

[DarkMatter]

On Sun, 21 Dec 2003 20:06:51 +0000, Tim Auton <tim.auton@uton.[group
sex without the y on the end]> Gave us:

DarkMatter <DarkMatter@thebarattheendoftheuniverse.org> wrote:
[snip]
Look, chucko. WIre size doubles every three gauges. That is what I
said, and that is what is true.

In fact... Three 22s makes a 19, and three more makes another 19.

Two 19s doesn't even make one 16 so seven 22s is most certainly
closer to a single 16 than it is your lame assed 14 claim.

Please, move on to the 20th century (if you can't manage the 21st) and
use metres (mm in this case). This is the perfect example of why
metric is overwhelmingly superior to the array of units that
constitute that various imperial systems still in use in some parts of
the world.

They were nice when we had to do calculations in our heads. Those days
ended decades ago. Move on.

So, you are saying that 3 22 gauge wires does not make a 19 Gauge
wire?

Clarify. Then move the fuk on.

 

[Ross Mac]

"Winfield Hill" <Winfield_member@newsguy.com> wrote in message
news:bs58qe022qd@drn.newsguy.com...

DarkMatter wrote...

Winfield Hill wrote:

I'll
venture that most commercial litz wire isn't fully woven, but
it performs much better than simple twisted strands.

You lose. Most commercial litz is simple twisted or even non
twisted bundling.

I'd appreciate it if you didn't so severely truncate my posts,
and then respond to an incomplete "answer" that I didn't give.

In fact, unless the number of strands is very small (i.e. one
layer after twisting, which is rare for litz) simple twisting
does NOT suffice to make litz wire. I've spec'd, purchased
and measured different types of litz from wire manufacturers.
Their solution to an inability to make a genuine weave is to
twist a modestly-small number of strands, then use multiple
sets of these as fatter wires in a secondary twist, then twist
sets of these thicker ropes to make up a completed wire. The
goal of multiple-layer schemes should be to move each individual
strand of wire through as many of the available locations within
the completed "cable" as possible, in such a manner that would
approximate the result from a true weave. One cannot do this
with simple twisting.

It's not useful to characterize the result as "twisted wire," and
certainly not "simple twisted," as you asserted. Litz performs
decidedly better than conventional twisted wire, simple or not.

Sadly, many (if not most) modified-twist schemes in fact fail to
fully distribute each wire's pathway throughout the complete area,
which can lead to substantial litz performance failures, with the
high-frequency Rac/Rdc exceeding unity in multilayer inductors and
transformers. Dark Matter, many of the examples on the cover-page
of your web-page reference would perform poorly against a properly-
designed litz wire (I see a few good prospects there as well).

Finally, I know of no wire manufacturer who makes simple bundles
of multi-strand insulated wire and calls this "litz wire." None
of the manufacturers I've used offer such a "weave" option, and
I would not purchase such wire if they did, because it would not
succeed in solving common severe proximity-effect problems.

Thanks,
- Win

whill_at_picovolt-dot-com

He does this often......that way he can quote "out of context"....kind of

bizarre huh....anyone who reads the thread sees what is going on.....

 

[DarkMatter]

On Sun, 21 Dec 2003 20:43:43 +0000, John Woodgate
<jmw@jmwa.demon.contraspam.yuk> Gave us:

Oh, no, John, no, John, no, John, no! Not if the turns are close-
coupled, as they are in a pot core.

Twice the turns equals 4 times the inductance.

It is easy. There is a square in the formula.

 

[DarkMatter]

On Sun, 21 Dec 2003 23:04:51 GMT, "Ross Mac"
<this.is.a.mung@example.invalid> Gave us:

If I ever have to build a custom choke, I know who to send my first message
to!....You certainly have a lot of experience in magnetics, as do a couple
of others on this thread...Pretty informative stuff....thanks...Ross
(Too bad DM mucked up the thread!)

You sure are a goddamned idiot.

 

[R.Legg]

John Fields <jfields@austininstruments.com> wrote in message news:<jkqbuvkurlkr4thpr1t1be47mlkl41eci9@4ax.com>...

On Sun, 21 Dec 2003 17:12:26 +0000, John Woodgate
jmw@jmwa.demon.contraspam.yuk> wrote:

I read in sci.electronics.design that DarkMatter <DarkMatter@thebaratthe
endoftheuniverse.org> wrote (in <8i7auvkadbh93ss7i7et2v4v4s5n6eg1p2@4ax.
com&gt about 'Help winding my own inductor?', on Sat, 20 Dec 2003:
They were either 27uH or
27mH.

I LIKE it! just a factor of 32 times as many turns. Expert? Ha!

---
1000 times, no, John?

Z = n˛ through a transformer, but for an inductor, L changes linearly
with n.

No. Inductance increases with the square of the turns.

RL

 

[John Fields]

On Sun, 21 Dec 2003 15:43:36 -0800, DarkMatter
<DarkMatter@thebarattheendoftheuniverse.org> wrote:

On Sun, 21 Dec 2003 13:00:10 -0600, John Fields
jfields@austininstruments.com> Gave us:

On Sun, 21 Dec 2003 09:48:25 -0800, DarkMatter
DarkMatter@thebarattheendoftheuniverse.org> wrote:

On Sun, 21 Dec 2003 10:35:43 -0600, John Fields
jfields@austininstruments.com> Gave us:

But not because of the diminution of skin effect, unless you're talking
RF.


Skin effect is the exact reason. Again, I can place the same number
of turns at the SAME circular mil area onto a core and get different
performance at different operating frequencies, and said performance
is HIGHER on the multi-strand configurations, and the reason IS skin
effect.

Where have you been?

---
Watching you bury yourself.

I thought people only had two feet, but you seem to have a never-ending
supply of them you use to insert into your mouth.


Quoted from a reputable magnet wire maker:

"The multistrand configuration minimizes the power losses otherwise
encountered in a solid conductor due to the "skin effect", or the
tendency of radio frequency current to be concentrated at the surface
of the conductor."

---
You seem to have missed that I posted this, which is included in your
post, above:

"But not because of the diminution of skin effect, unless you're talking
RF."

You must have also missed that there's no confict between what I posted
and what your "reputable magnet wire maker" posted, namely that skin
effect only becomes pronounced at radio frequencies (RF).

In any case, regardless of what you may think, your seven-strand affair
is _not_ a piece of litz wire, and will _never_ porform as well as litz
wire will at radio frequencies.

You really ought to Google "skin effect" and find the relationship
between frequency and concentration of current in a conductor to find
out how really stupid the pseudo-knowledgeable spew you've been writng
makes you sound.

--
John Fields

 

[John Fields]

On Sun, 21 Dec 2003 15:46:45 -0800, DarkMatter
<DarkMatter@thebarattheendoftheuniverse.org> wrote:

On Sun, 21 Dec 2003 13:11:29 -0600, John Fields
jfields@austininstruments.com> Gave us:

If you think a Litz-wound choke has anything to do with better operation
of a linear supply because of skin effect then I suggest that the threat
to your livelihood which I pose, as you claimed in a previous post,
diminishes to zero when compared to the threat you pose to yourself.

You an idiot. We just made a big linear, and it operates at 19kHz.
Quite sufficient for skin effect to make a difference.

---
Really? How about if you post the difference between DC resistance and
AC resistance of the choke winding(s) due to skin effect and the
difference that resistance makes in the inductance of the choke because
of the differences in current flowing in the winding because of skin
effect at 19kHz, OK?
---

In fact, the solid wire choke made the unit fall out of spec on the
ripple figure of 10mV at 1500V out.

---
Fine, but you don't know that the stranded wire choke made it pass
because of anything having to do with skin effect.
---

We don't make toys.

I'm sure the folks you work for are good guys who know what they're
doing...

--
John Fields

 

[Ross Mac]

"DarkMatter" <DarkMatter@thebarattheendoftheuniverse.org> wrote in message
news:jidcuvg7a0g1qli0bfq2kooscqu2d4pur0@4ax.com...

On Sun, 21 Dec 2003 23:04:51 GMT, "Ross Mac"
this.is.a.mung@example.invalid> Gave us:


If I ever have to build a custom choke, I know who to send my first
message
to!....You certainly have a lot of experience in magnetics, as do a
couple
of others on this thread...Pretty informative stuff....thanks...Ross
(Too bad DM mucked up the thread!)

You sure are a goddamned idiot.
The usual monosyllabic troll response.......Have a nice day DopeMatter!