Re: AC wire resistance with proximitry effects

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>

Hi Gerry,

Tesla list wrote:

> Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>
>
> Hi Bart,
>
> I'll be happy to write a little program to independently compute Rf 
> and Q if you send me the collection of data (including Ldc, Cdc, 
> Les, Ces, Qmeas, etc)  for a variety of coils.

Sure, that might help a great deal. I'll be sending you the 
spreadsheet tonight. There's more data we could add, however, the 
rest really go outside the ability to make a meaningful conclusion. 
It's best at this time to keep the coils as similar as possible. I 
don't mind h/d variation, but topload variations, space wound, etc... 
will highly confuse what were looking at. Should you throw together a 
program, you may want to keep it somewhat simple in that respect. All 
should be well with the spreadsheet now.

> This would be a good cross check on the java (or spreadsheet) 
> implementation.  When you speak of Q error, are you comparing to the 
> measured Q by the coil data provider???

Yes, exactly. I know there are more losses not accounted for and each 
coil has unique losses. I think you'll see that in the spreadsheet 
for some coils. You will certainly see similarities with h/d as well.

> The main reason for thinking that Les and Ces are the right values 
> to use is the transfer function that defines Q is based on the L and 
> C that correctly predicts the resonance that we are measuring Q for.

Yes, I'm incline to agree with you now. A few years ago I was trying 
to come up with an equivalent Rac for the purpose of a meaningful Q 
calculation. It's something I had in an old excel version. I don't 
believe I ever sent that portion of it out as it was one of those 
(calc's on trial) cells.  I was using Paul Nicholson's Les and Ces 
differential equations. It was always hard to tell how well it would 
do (just using my own coils for checks makes it about impossible to 
know). But now, I can actually pull it in for at least a comparison. 
It faired rather well. It's in the spreadsheet. I'll send off tcml.

Take care,
Bart



> > Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>
> >
> > I have tried using Les and Ces with Fraga, but I have seen Q error 
> > increase when I've tried it with Fraga. However, tonight I found an 
> > error with effective Rho. I had parenthesis wrong as well as a 2* 
> > where it didn't belong. So, all is lost :-( . (well, not all). As 
> > soon as I corrected it, Fraga Q went high and now I can see why you 
> > are contemplating Les. It would certainly make the numbers better.
> >
> > What does concern me however is even current distribution was an 
> > assumption in their work.
> >
> > I'll have to go all back through  it.
> >
> > Thanks for being persistent.
>
>
> Well, that's my middle name :o)))
>
> Take care,
> Gerry R