Re: which coilform parameters best?

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <FutureT-at-aol-dot-com>

In a message dated 4/13/02 7:19:40 PM Eastern Daylight Time, tesla-at-pupman-dot-com
writes:

John,

I agree with Bart here.  I see no reason to make the coil so
short, unless you have limited ceiling space, etc.  A taller
coil lets things run more freely, i.e. the sparks are less likely
to arc down and hit the primary.  There's certainly nothing
wrong with using a 4:1, or 5:1 ratio.  Actually I prefer such
ratios.  Probably the only advantage of using a wider 
secondary is to lower the resonant frequency, which can
make the quenching a little easier perhaps.   In any case,
I would use the 10" form, and make it 40 to 50" tall.  I'd use
about 1000 turns of wire, maybe more.  Yes, larger is better
as someone said.  More voltage and input power is better
too, so I'd use the two pigs for 14.4kV as Bart suggested.
The actual length of the secondary wire itself doesn't matter,
if all else is correct.

Cheers,
John

>
> , the top
> of the coil will only be 30" away from the primary if flat, and closer if
> helical or conical.
> Considering arc lengths you can expect using a 5 or 10 kva pig, you might
> want to consider something
> nearer to 4 or 5:1 h/d ratio. This would add turns to both coils and
> increase the distance between the
> top terminal and primary. Also, I would go for a 10kva pig. The 5kva will
> be fine at 120 bps, but
> because of the large cap size and slow charge time, I think you would end
> up happier with a 10kva pig in
> the long run.
>
> Take care,
> Bart