RE: What size secondary?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Lau, Gary" <Gary.Lau@xxxxxx>

Hi Stephen:

I have found that bigger is almost always better.  Using a larger
secondary coil forces you to use a larger top load, and these two things
in turn require a larger primary coil.  The use of a higher-inductance
primary coil reduces the current through the spark gap, which reduces
spark gap losses.  It may also be that the lower resonant frequency
incurs less skin-effect losses.  Beyond this nice theory, I have seen
that my mini coil, powered by a 4kV/20mA NST, performs better with a 4"
secondary, as compared with its original 2" secondary (primary cap & top
load remained unchanged).

I would definitely choose the 6" secondary for your coil.  Choosing the
top load size is more critical.  If it's too large, you won't get any
discharge, but in my experience, we usually make it too small for
reasons of economy and aesthetics.  Smaller will always work - just not
as well as a larger, right-sized top load.

Regards, Gary Lau
MA, USA




> Original poster: "stephen costanza" <baywatch106@xxxxxxx>
>
> I have a 12000 60ma NST,will be using the cd 942's and 24ga magnet
> wire. What size secondary should I use? I've been looking  and some
> people are using 4" pvc and some are using 6'' pvd diameter .
> I orginally was planning using 4" pvc with a toilet flange to support
> the secondary.
> Any ideas on what size is best? I