RE: Effective Resistance

["John H. Couture" <couturejh-at-worldnet.att-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Malcolm -

You pointed out the problem by using your example. There is more than one
type of Q factor with Tesla coils. If you use the wrong Q factor you get 2.7
MV of voltage. You must use the operating Q factor to get the correct
voltage. You will find this Q by using the correct Reff resistance. The
problem is to find the correct Reff resistance (ESR?). How do you do that?
Refer to my post "Q Factor and Overall Efficiency". What are your comments?

Coilers have been banging this Q factor problem around for years. It usually
ends up with no agreement amongst the coilers. However, if you are to
include the Q factor and effective resistance in a program like the JHCTES I
believe doing something with the data you have available is better than
doing nothing. More data is needed. But it's the same old problem. There are
not enough coilers like you who go beyond the spark stage and do more
testing of their coils.

John Couture

--------------------------------


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Sunday, August 27, 2000 11:21 PM
To: tesla-at-pupman-dot-com
Subject: RE: Effective Resistance


Original poster: "Malcolm Watts" <M.J.Watts-at-massey.ac.nz>

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

--------------------------  snip


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.

-------------------------- snip

  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