Re: AC wire resistance with proximitry effects

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Bart,

> Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>
>
> Hopefully the same one your using.
>
> Rf = [2pi*N^2*a* effective_rho*(sinh(2theta)+sin(2theta)) ]  /
>        [effective_sd*Lw*(cosh(2theta)-cos(2theta)) ]
>
> I assume you ask because you are getting something different?

I'm asking because I didn't see a Q equation by Fraga.  Only a Rf 
equation. I'm assuming from subsequent posts that you are using 
WoL/Rf for Q.  I've kept your coil data post and maybe you could say 
what you used for L (Ldc or Les).


> I didn't put theta in radians. The equation appears to be a classic 
> cos(radians(x)), etc...  but I got something off in nevernever land 
> when I set it up. I then removed rads and Q popped up where 
> expected. I left it that way.

I'll try to figure this out too cause I see nothing in the theta 
definition that would suggest degrees (maybe its grads :o))   May 
have to email Gary on this one.


> I have noted that eff_sD is quite a bit higher than other approximations make.

I believe it is altered because of how he stretches a square wire 
into a rectangular one but not sure of the basis of this.  I'll look 
at his definition more closely.

> I'm in the middle of entering coils into the spreadsheet and 
> currently going through Malcolms data concentrating mainly on the 
> closewound coils. A day or so ago I entered Kurt Schraners' data as 
> he made quite a few precise measurements of different h/d coils. 
> I'll send my spreadsheet your way once I get some of Malcolms data 
> logged. I could sure use a check on the implementation.

Sounds good.

Take care,
Gerry R.