RE: Effective Resistance

["Malcolm Watts" <M.J.Watts-at-massey.ac.nz> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi John,
          I don't think there is too much of a problem here:

On 25 Aug 00, at 19:50, Tesla list wrote:

> Original poster: "John H. Couture" <couturejh-at-worldnet.att-dot-net> 
> 
> 
> Boris -
> 
> I know that most coilers are interested in only long sparks but a few
> coilers are also interested in what makes those sparks do their thing and
> how can they be made to do better.  For several years I have been working on
> developing a TC computer program that can help in understanding the
> classical TC. I am still working on it. Many coilers have their own programs
> that they have made. However, to my knowledge none of these programs are
> comprehensive enough to include all of the major TC parameters and
> coordinate them into one interactive program. I am referring to empirical
> type programs which model Tesla coils by using both theory and empirical
> data.
> 
> To keep this short I will refer to only one of these parameters and that is
> the secondary terminal voltage (Vs). There are several ways to estimate this
> parameter but they all require knowing the overall efficiency which is an
> unknown. However, there is one method that does not require efficiency and
> that is the equation
>      Vs = Vp * Q

I presume that means that my coil which has an unloaded Q of 
300 odd and a primary voltage of 9kV is generating 2.7MV!!!???
I can assure you it isn't. More like 300kV actually. That 
equation only applies to a CW-driven coil with no breakout. 

> where Vs is the secondary voltage, Vp is the peak primary voltage, and Q is
> the operating Q factor. The operating Q factor is only one of several TC Q
> factors. The Q factor is found by the equation
>       Q = Xl/Reff
> where Xl = 6.283 * Fres * L   and Reff is the effective resistance. But
> first of all the Reff must be cleary defined. For example is Reff the ESR
> that coilers talk about? The ESR is referred to as an impedance but the Reff
> can not be an impedance. The Reff is a loss type ohms. An impedance is the
> sq rt of the squares of the active and reactive ohms. Note that there are
> three types of ohms in the electrical world, active, reactive, and
> impedance.

ESR = Equivalent Series *RESISTANCE*. Disipative resistance - 
no complex impedances in there.

Regards,
Malcolm
 
> As you can see there is much more to the design and engineering of the Tesla
> coil once you get beyond the spark stage.
> 
> John Couture
>