Re: AC wire resistance with proximitry effects

["Tesla list" <tesla@xxxxxxxxxx>]

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

Hi Malcolm,

I agree, defining R as ESR is quite correct.  My statement that I 
thought it was :the wrong equation" was a brain fart (I should have 
looked at the derivation more closely).  The equations are the same 
if one uses the correct "w" and L.  "w" should be sqrt (1/LC) and not 
the peak response. These two become one of the same as ESR -> zero, 
but as ESR becomes larger, the peak response lowers in frequency 
while Wo does not (think root locus). For resonable Q coils the 
differenct between Wo and peak response is probably negligible.  The 
other question (and perhaps most significant)  is what is used for 
L.  I believe Ldc is wrong for this.  The effective L and C (Les and 
Ces used in Javatc) that determine the infinite Q resonant frequency 
are what I believe should be used.  Thankyou for bringing this up.

Gerry R.

> Original poster: "Malcolm Watts" <m.j.watts@xxxxxxxxxxxx>
>
> On 10 Oct 2005, at 11:47, Tesla list wrote:
>
> > Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>
> >
> > Hi Bart,
> >
> > I understand now what you are saying.  One thing I might question is
> > your equation for Q.  I dont think this is the right equation for a
> > series RLC circuit:
> >
> > The RLC Laplace impedance is sL + R + 1/sC
> >
> > I(s) = V(s) / sL+R+1/sC
> >
> > to put in standard form:
> >
> > I(s)/V(s) =  (s/L) / (s^2 + sR/L + 1/LC) = (s/L) / (s^2 + s Wo/Q +
> > Wo^2)
> >
> > Wo =  sqrt (1/LC)
> >
> > R/L = Wo/Q
> >
> > Q = WoL/R = sqrt (L/C) / R
> >
> > Gerry R
> >
> >
> > >Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>
> >
> > >First, regarding Ldc. Your right, it's not in the equation for
> > >Fraga, but it is used when predicting Q. Here is what I'm doing, at
> > >least at this time.
> > >
> > >ESR = wL/Q
> > >Q = wL/ESR
> > >I am replacing ESR with Fraga's resistance because it is a combined
> > >R.
>
> I'm struggling to see a difference apart from Bart defining "R" as
> "ESR" which is quite correct.
>
> ??
> Malcolm
>
> >
> >
> >
> >
> >