Re: Skin Effect
From: Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: Sunday, August 03, 1997 4:28 PM
Subject: Re: Skin Effect
If I might comment also....
> From: Robert Davis[SMTP:RE.Davis-at-btinternet-dot-com]
> Sent: Sunday, August 03, 1997 9:27 AM
> To: 'Tesla List'
> Subject: RE: Skin Effect
> Dear DR.RESONANCE,
> Sorry the calculation was not clear. I used the X as multiplication.
> In the second calculation for effective wire resistance the skin depth
> term varies with frequency. Also the lower case r was a typing
> mistake. The ^ symbol meaning, to the power of. The 66 in the first
> formula becomes 0.066 after converting skin depth in mm to meters.
> The full equation is given below (without multiplication symbols)
> after substituting the first formula for the skin depth term:
> Dynamic Resistance = L/C((PiR^2)-(Pi(R-(0.066/sqrt(F)))^2))
> F = Frequency (Hz)
> L = Length of wire (m)
> R = Radius of Conductor (m)
> C = Conductivity of copper = 5.8 x 10^7
> Pi = 3.1415927
> In the above I use sqrt() as the square root function.
Firstly, 66/sqrt(f) gives the skin depth in mm at frequency f for
copper or at least one grade of it. Resistivity/conductivity is
already factored into this equation. Seems superfluous to use it