Re: Twin Coil Systems.

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz <twftesla-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>

Tesla list wrote:
 
> Original poster: "Neil Richardson by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <neil-at-opticalrealities-dot-com>
> 
> I was thinking of building one with a friend since they produce longer arcs,
> and basically look nicer :)
> 
> I was wondering - do the primaries have to be connected in series or
> parallel. I was thinking of parallel, but if they weren't tapped at exactly
> the right point, the system would not work. In series, I would add the 2
> inductances right? 

The primaries can be in series or in parallel. The system will work
as expected if the symmetry is good enough in any case. The series 
connection is just simpler.

> And about the secondaries - I know you must wind one
> clockwise, the other counterclockwise, and connect their grounds together -

Or you can invert the direction of one of the primaries and use 
identical secondaries.

> but what about their inductance and self capacitance? Would they be like 2
> capacitors in parallel or series? Cos if I plan to build a twin coil system
> I need to know how to make it work well first time, I want my first real
> tesla coil attempt to be something to show off about :)

Inductances and equivalent capacitances are in series. The inductances 
add, and the capacitances are divided by 2 (assuming that the
secondaries
and terminals are far enough. Otherwise the capacitances will look 
somewhat larger due to mutual capacitance, and the inductances will look
smaller or larger, depending on the winding directions). 
The tuning relation for primaries in series is:

C1*(2*L1)=(2*L2)*(C2/2)

It's possible to derive tuning relations for asymmetrical twin systems 
too, but the symmetrical case is much simpler.

Antonio Carlos M. de Queiroz