Coil formula

  • Thread starter Dirk Bruere at Neopax
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Dirk Bruere at Neopax

Guest
Any got a pointer to the formula for inductance and field strength for a given
current for a large dia air core coil? Dia>>length or winding thickness

thanks
Dirk

The Consensus:-
The political party for the new millenium
http://www.theconsensus.org
 
"Dirk Bruere at Neopax" <dirk@neopax.com> wrote in message
news:36580bF4r9jtiU1@individual.net...
Any got a pointer to the formula for inductance and field
strength for a given
current for a large dia air core coil? Dia>>length or winding
thickness

thanks
Dirk
http://www.fnrf.science.cmu.ac.th/theory/magnets/An%20introduction%20to%20the%20air%20cored%20coil.html
Click to expand...

As a start. Not all you wanted, but a start!!!!
 
Clarence_A wrote:

"Dirk Bruere at Neopax" <dirk@neopax.com> wrote in message
news:36580bF4r9jtiU1@individual.net...

Any got a pointer to the formula for inductance and field

strength for a given

current for a large dia air core coil? Dia>>length or winding

thickness

thanks
Dirk

http://www.fnrf.science.cmu.ac.th/theory/magnets/An%20introduction%20to%20the%20air%20cored%20coil.html

As a start. Not all you wanted, but a start!!!!
Click to expand...
Thanks, but I've already seen it.
I was hoping for a 'finished' formula so I wouldn't have to spend a few hours
messing around with stuff since I'll be juggling several other variables besides
the obvious ones.
Actually, a better version of the above is here:
http://www.ee.surrey.ac.uk/Workshop/advice/coils/air_coils.html


--
Dirk

The Consensus:-
The political party for the new millenium
http://www.theconsensus.org
 
I read in sci.electronics.design that Dirk Bruere at Neopax
<dirk@neopax.com> wrote (in <36580bF4r9jtiU1@individual.net>) about
'Coil formula', on Sun, 30 Jan 2005:
Any got a pointer to the formula for inductance and field strength for a given
current for a large dia air core coil? Dia>>length or winding thickness

Inductance = 1.6 uH per metre of turn length, for one turn, if the
Click to expand...
conductor diameter is much smaller than the coil diameter. For more
turns, if closely-coupled, multiply by the square of the number of
turns.

At what point do you want to know the field strength? At an arbitrary
point, it involves elliptic functions, but some points are degenerate
and give simple results.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
 
On Sun, 30 Jan 2005 15:50:54 -0800, John Larkin
<jjSNIPlarkin@highTHISlandPLEASEtechnology.XXX> wrote:

On Sun, 30 Jan 2005 23:13:19 +0000, Dirk Bruere at Neopax
dirk@neopax.com> wrote:

Any got a pointer to the formula for inductance and field strength for a given
current for a large dia air core coil? Dia>>length or winding thickness

thanks
Dirk

The Consensus:-
The political party for the new millenium
http://www.theconsensus.org
Click to expand...
Oops, Jennifer's prog got pasted twice.

John
 
"Dirk Bruere at Neopax" <dirk@neopax.com> wrote in message
news:3659pkF4tbqd3U1@individual.net...

" Thanks, but I've already seen it.

I was hoping for a 'finished' formula.

You know, that one with the sum that don't include that there fancy math and
references to french people.

Just so I wouldn't have to spend a few hours fucking around with the locals.

I'll be juggling several other variables besides the obvious ones."

> Dirk
 
On Sun, 30 Jan 2005 23:44:10 +0000, John Woodgate
<jmw@jmwa.demon.contraspam.yuk> wrote:

I read in sci.electronics.design that Dirk Bruere at Neopax
dirk@neopax.com> wrote (in <36580bF4r9jtiU1@individual.net>) about
'Coil formula', on Sun, 30 Jan 2005:
Any got a pointer to the formula for inductance and field strength for a given
current for a large dia air core coil? Dia>>length or winding thickness

Inductance = 1.6 uH per metre of turn length, for one turn, if the
conductor diameter is much smaller than the coil diameter. For more
turns, if closely-coupled, multiply by the square of the number of
turns.
Click to expand...
As the conductor diameter trends towards zero, the inductance becomes
infinite.

John
 
John Woodgate wrote:

I read in sci.electronics.design that Dirk Bruere at Neopax
dirk@neopax.com> wrote (in <36580bF4r9jtiU1@individual.net>) about
'Coil formula', on Sun, 30 Jan 2005:

Any got a pointer to the formula for inductance and field strength for a given
current for a large dia air core coil? Dia>>length or winding thickness


Inductance = 1.6 uH per metre of turn length, for one turn, if the
conductor diameter is much smaller than the coil diameter. For more
turns, if closely-coupled, multiply by the square of the number of
turns.
Click to expand...
How accurate is that?
Given, for example a coil with one metre dia and (say) 100 turns of #24?

At what point do you want to know the field strength? At an arbitrary
point, it involves elliptic functions, but some points are degenerate
and give simple results.
Click to expand...
Well, I suppose the centre might be a good starting point.
Typical coil dia would be around one metre.
Also two metres from centre in the plane of the coil.

--
Dirk

The Consensus:-
The political party for the new millenium
http://www.theconsensus.org
 
Dirk Bruere at Neopax wrote:

The Consensus:-
The political party for the new millenium
http://www.theconsensus.org
Click to expand...
Sorry I'm not helping, except that, what is a millenium?

--
Ian Stirling, G4ICV, AB2GR, Long Valley, New Jersey, USA.
Email address is not valid: contact details are on that
domain's web site.
 
Genome wrote:

"Dirk Bruere at Neopax" <dirk@neopax.com> wrote in message
news:3659pkF4tbqd3U1@individual.net...

" Thanks, but I've already seen it.

I was hoping for a 'finished' formula.

You know, that one with the sum that don't include that there fancy math and
references to french people.

Just so I wouldn't have to spend a few hours fucking around with the locals.

I'll be juggling several other variables besides the obvious ones."
Click to expand...
True, its a real pain fucking around with the locals, or at least some of them.

--
Dirk

The Consensus:-
The political party for the new millenium
http://www.theconsensus.org
 
Donna and Ian wrote:

Dirk Bruere at Neopax wrote:


The Consensus:-
The political party for the new millenium
http://www.theconsensus.org


Sorry I'm not helping, except that, what is a millenium?
Click to expand...
Its like 'millennium' but shorter.
A bit like 'It's' without an apostrophe.

--
Dirk

The Consensus:-
The political party for the new millenium
http://www.theconsensus.org
 
On Sun, 30 Jan 2005 19:10:45 -0500, Donna and Ian <ian@opus131.com>
wrote:

Dirk Bruere at Neopax wrote:


The Consensus:-
The political party for the new millenium
http://www.theconsensus.org

Sorry I'm not helping, except that, what is a millenium?
Click to expand...


It's 1/1000 of a lenium.


John
 
John Larkin wrote:

On Sun, 30 Jan 2005 19:10:45 -0500, Donna and Ian <ian@opus131.com
wrote:

Dirk Bruere at Neopax wrote:


The Consensus:-
The political party for the new millenium
http://www.theconsensus.org

Sorry I'm not helping, except that, what is a millenium?



It's 1/1000 of a lenium.
Click to expand...
agreed, but what is a lenium?
I know about lenniums.

--
Ian Stirling, G4ICV, AB2GR, Long Valley, New Jersey, USA.
Email address is not valid: contact details are on that
domain's web site.
 
"John Larkin" <jjSNIPlarkin@highTHISlandPLEASEtechnology.XXX> wrote in
message news:p5tqv09hp85tvulonb682nihhlf5crokhi@4ax.com...
On Sun, 30 Jan 2005 15:50:54 -0800, John Larkin
jjSNIPlarkin@highTHISlandPLEASEtechnology.XXX> wrote:

On Sun, 30 Jan 2005 23:13:19 +0000, Dirk Bruere at Neopax
dirk@neopax.com> wrote:

Oops, Jennifer's prog got pasted twice.

John
Click to expand...
Uo is 4piE-7.

That's in SI units.

Which have been established as being established by the French, I think.

I assume that SouthPark might have something to say about this because they
take the piss out off Scotts speaking french people and had war with the
Americans, who are basically Irish......

What the fuck you are doing calling your company Highland Technology for?
(and making me take care over the spelling) is another thing, perhaps you
are denying your heritage.

Speff's Canadian (and he'd better not be fucking about with that one if I'm
not going to get overly disillusioned about the general state of things)

The Aylward appears to have claimed to be a nigger, but he's an export.....
so he's not an Indian. It's not that they write better software they are
just cheaper.... Sorry I read that Kevin has embedded something so deep in
his code that he would rather not be arsed getting it out again.


Which, taking Jennifer's sums, should be 12.57E-7.

Now, I know you Americans have had some problem in the past with the odd
factor of something like 4E8 or the odd erg slug foot cubit.

But!!!!!!!!! You now come along with your Power Penis.

DisFuckingGusting. Wot you want is one of these.

unit roundedit;

interface

uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
Grids, DBGrids, Db, DBTables, ToolWin, ComCtrls, Menus, DBActns,
ActnList, ImgList, ExtCtrls, DBCtrls, Math, Spin, StdCtrls, FileCtrl;

type
TRoundWireForm = class(TForm)
DataSource1: TDataSource;
Table1: TTable;
ToolBar1: TToolBar;
ImageList1: TImageList;
ActionList1: TActionList;
DataSetFirst1: TDataSetFirst;
DataSetLast1: TDataSetLast;
DataSetNext1: TDataSetNext;
DataSetPrior1: TDataSetPrior;
ToolButton1: TToolButton;
ToolButton2: TToolButton;
ToolButton3: TToolButton;
ToolButton4: TToolButton;
ToolButton5: TToolButton;
ToolButton6: TToolButton;
DataSetInsert1: TDataSetInsert;
ToolButton7: TToolButton;
DataSetCancel1: TDataSetCancel;
DataSetPost1: TDataSetPost;
ToolButton8: TToolButton;
ToolButton9: TToolButton;
DataSetDelete1: TDataSetDelete;
DBGrid1: TDBGrid;
Table1Standard: TStringField;
Table1CuDiamm: TFloatField;
Table1DiaLmm: TFloatField;
Table1DiaSmm: TFloatField;
Table1DiaHmm: TFloatField;
Table1DiaTmm: TFloatField;
MainMenu1: TMainMenu;
File1: TMenuItem;
Exit1: TMenuItem;
GroupBox1: TGroupBox;
Label1: TLabel;
Label2: TLabel;
Label3: TLabel;
Flabel: TLabel;
Llabel: TLabel;
Tlabel: TLabel;
FUpDown: TUpDown;
LUpDown: TUpDown;
TUpDown: TUpDown;
LightRadio: TRadioButton;
SingleRadio: TRadioButton;
HeavyRadio: TRadioButton;
TripleRadio: TRadioButton;
GroupBox2: TGroupBox;
Label4: TLabel;
Label5: TLabel;
Label6: TLabel;
RdcLabel: TLabel;
RacLabel: TLabel;
RraLabel: TLabel;
Label7: TLabel;
Label8: TLabel;
Table1Guage: TFloatField;
procedure Exit1Click(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure DataSource1DataChange(Sender: TObject; Field: TField);
procedure FUpDownClick(Sender: TObject; Button: TUDBtnType);
procedure LUpDownClick(Sender: TObject; Button: TUDBtnType);
procedure TUpDownClick(Sender: TObject; Button: TUDBtnType);
procedure LightRadioClick(Sender: TObject);
procedure SingleRadioClick(Sender: TObject);
procedure HeavyRadioClick(Sender: TObject);
procedure TripleRadioClick(Sender: TObject);
private
{ Private declarations }
procedure Recalc;
public
{ Public declarations }
end;

var
RoundWireForm: TRoundWireForm;

implementation

{$R *.DFM}

procedure TRoundWireForm.Recalc;
var
Resistivity : double;
SkinDepth : double;
CuDiametre : double;
InsDiametre : double;
Height : double;
LayFact : double;
Quality : double;
Mac : double;
Dac : double;
Fratio : double;
DCResistance : double;
ACResistance : double;
begin
If LightRadio.Checked=True then
InsDiametre := Table1.FieldByName('Dia (L) / mm').AsFloat/1000;
If SingleRadio.Checked=True then
InsDiametre := Table1.FieldByName('Dia (S) / mm').AsFloat/1000;
If HeavyRadio.Checked=True then
InsDiametre := Table1.FieldByName('Dia (H) / mm').AsFloat/1000;
If TripleRadio.Checked=True then
InsDiametre := Table1.FieldByName('Dia (T) / mm').AsFloat/1000;
CuDiametre := Table1.FieldByName('Cu Dia / mm').AsFloat/1000;
If (InsDiametre>0) and (CuDiametre>0) then
begin
Resistivity := 1.72417E-8*(1+0.00393*(TUpDown.Position-20));
SkinDepth := Sqrt(Resistivity/(pi*4*pi*1E-7*1000*FUpDown.Position));
Height := CuDiametre*Sqrt(pi/4);
LayFact := CuDiametre/InsDiametre;
Quality := Sqrt(LayFact)*Height/SkinDepth;
Mac :=
Quality*(sinh(2*Quality)+sin(2*Quality))/(cosh(2*Quality)-cos(2*Quality));
Dac := 2*Quality*(sinh(Quality)-sin(Quality))/(cosh(Quality)+cos(Quality));
Fratio := Mac+Dac*(Sqr(LUpDown.Position)-1)/3;
DCResistance := Resistivity/(Sqr(CuDiametre/2)*pi);
ACResistance := Fratio*DCResistance;
RdcLabel.Caption := FloatToStrf(DCResistance,ffGeneral,5,0);
RacLabel.Caption := FloatToStrf(ACResistance,ffGeneral,5,0);
RraLabel.Caption := FloatToStrf(Fratio,ffGeneral,5,0);
end
else
begin
RdcLabel.Caption := 'Not Available';
RacLabel.Caption := 'Not Available';
RraLabel.Caption := 'Not Available';
end;
end;

procedure TRoundWireForm.Exit1Click(Sender: TObject);
begin
close;
end;

procedure TRoundWireForm.DataSource1DataChange(Sender: TObject;Field:
TField);
begin
Recalc;
end;

procedure TRoundWireForm.FUpDownClick(Sender: TObject;
Button: TUDBtnType);
begin
Flabel.Caption := IntToStr(FUpDown.Position);
Recalc;
end;

procedure TRoundWireForm.LUpDownClick(Sender: TObject;
Button: TUDBtnType);
begin
Llabel.Caption := IntToStr(LUpDown.Position);
Recalc;
end;

procedure TRoundWireForm.TUpDownClick(Sender: TObject;
Button: TUDBtnType);
begin
Tlabel.Caption := IntToStr(TUpDown.Position);
Recalc;
end;

procedure TRoundWireForm.LightRadioClick(Sender: TObject);
begin
Recalc;
end;

procedure TRoundWireForm.SingleRadioClick(Sender: TObject);
begin
Recalc;
end;

procedure TRoundWireForm.HeavyRadioClick(Sender: TObject);
begin
Recalc;
end;

procedure TRoundWireForm.TripleRadioClick(Sender: TObject);
begin
Recalc;
end;

procedure TRoundWireForm.FormCreate(Sender: TObject);
begin
Label1.Caption := 'Frequency KHz';
Label2.Caption := 'Layers';
Label3.Caption := 'Temperature C';
Label4.Caption := 'DC Resistance/m';
Label5.Caption := 'AC Resistance/m';
Label6.Caption := 'Rac/Rdc Ratio';
Flabel.Caption := IntToStr(FUpDown.Position);
Llabel.Caption := IntToStr(LUpDown.Position);
Tlabel.Caption := IntToStr(TUpDown.Position);
HeavyRadio.Checked := True;
end;
end.
 
"Donna and Ian" <ian@opus131.com> wrote in message
news:iOadnUjZ2ck36mDcRVn-pA@comcast.com...
Dirk Bruere at Neopax wrote:


The Consensus:-
The political party for the new millenium
http://www.theconsensus.org

Sorry I'm not helping, except that, what is a millenium?

--
Ian Stirling,
Click to expand...
In case you missed it we had a New One.

It's like it's dead special...

Like you think a Millenium has something to do with a Million things.

It was probably something invented by Greeks and adopted by the Romans so it
got divided by a thousand, you know, like towards the end.

Like in modern times.... third fourth and fifth reich. Cherry blossoms of
the doodad.

Yup, this ones going to last a 'mill' oo0ps thousand years. Oh bugger we got
fucked over, shit.





Hey! folks. It's a new Millenium.......

And, just in case your thinking we're going to tell you that we sure aint
going to fuck you over again... just don't forget that it's all worth 9.99
in the new currency.

DNA
 
On Mon, 31 Jan 2005 01:00:50 GMT, "Genome" <ilike_spam@yahoo.co.uk>
wrote:

What the fuck you are doing calling your company Highland Technology for?
(and making me take care over the spelling) is another thing, perhaps you
are denying your heritage.
Click to expand...
Irish, German, dark rumors of a trace of French and possibly even a
bit of converted Jew somewhere.

I used to live on Highland Avenue and decided to incorporate and my
expensive lawyer called me and asked for the company name to file the
papers, so I said you-know-what. Never paid him, come to think of it.

Our company logo depicts the view looking at Mount Tamalpias as seen
from the toll plaza of the Bay Bridge. The moon thing is Artistic
License, of course.


Which, taking Jennifer's sums, should be 12.57E-7.
Click to expand...
If you want the field in Tesla, which she apparently didn't.


John
 
"John Larkin" <jjSNIPlarkin@highTHISlandPLEASEtechnology.XXX> wrote in
message news:aa2rv0t0a0qsrmt822vj9qj67b9b5rs6h2@4ax.com...
On Mon, 31 Jan 2005 01:00:50 GMT, "Genome" <ilike_spam@yahoo.co.uk
wrote:

Which, taking Jennifer's sums, should be 12.57E-7.


If you want the field in Tesla, which she apparently didn't.


John
Click to expand...
Gauss.....

Just like a Texan.

DNA
 
On Mon, 31 Jan 2005 01:29:07 GMT, "Genome" <ilike_spam@yahoo.co.uk>
wrote:

"Donna and Ian" <ian@opus131.com> wrote in message
news:iOadnUjZ2ck36mDcRVn-pA@comcast.com...
Dirk Bruere at Neopax wrote:


The Consensus:-
The political party for the new millenium
http://www.theconsensus.org

Sorry I'm not helping, except that, what is a millenium?

--
Ian Stirling,

In case you missed it we had a New One.

It's like it's dead special...

Like you think a Millenium has something to do with a Million things.

It was probably something invented by Greeks and adopted by the Romans so it
got divided by a thousand, you know, like towards the end.

Like in modern times.... third fourth and fifth reich. Cherry blossoms of
the doodad.

Yup, this ones going to last a 'mill' oo0ps thousand years. Oh bugger we got
fucked over, shit.





Hey! folks. It's a new Millenium.......

And, just in case your thinking we're going to tell you that we sure aint
going to fuck you over again... just don't forget that it's all worth 9.99
in the new currency.

DNA
Click to expand...
Couldn't have said that better myself.

John
 
"Dirk Bruere at Neopax" <dirk@neopax.com> wrote in message
news:3659pkF4tbqd3U1@individual.net...
Just so I wouldn't have to spend a few hours fucking around with the
locals.

I'll be juggling several other variables besides the obvious ones."

True, its a real pain fucking around with the locals, or at least some of
them.

Dirk
Click to expand...
Shit, I've only got two of the locals. I usually spend heavy time on the
primary and treat my locals real gentle whilst stroking the odd secondary.

You seem to have more locals than myself. I couldn't afford to waste one
because I'm not into that machocism type stuff and, I kind of assume, they
don't grow back too quickley.

I'd really like to know about your extra variables though.


DNA
 
Genome wrote:
"Dirk Bruere at Neopax" <dirk@neopax.com> wrote in message
news:3659pkF4tbqd3U1@individual.net...
Just so I wouldn't have to spend a few hours fucking around with the

locals.

I'll be juggling several other variables besides the obvious ones."

True, its a real pain fucking around with the locals, or at least some of

them.

Dirk


Shit, I've only got two of the locals. I usually spend heavy time on the
primary and treat my locals real gentle whilst stroking the odd secondary.

You seem to have more locals than myself. I couldn't afford to waste one
because I'm not into that machocism type stuff and, I kind of assume, they
don't grow back too quickley.

I'd really like to know about your extra variables though.
Click to expand...
Given the dia of coil is large eg >1m field strength at different points for
different power inputs (current) at various frequencies. Even the latter are not
well defined since they are pseudorandom pulse trains in the hundreds of Hz.
Then we have coil resistance, power handling, wire dia etc
Simplified somewhat given that I am assuming it will be driven by hi power audio
amps, so DC into 4 ohms is worst case.

--
Dirk

The Consensus:-
The political party for the new millenium
http://www.theconsensus.org
 
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