Re: Barts Coil Desing (was flashing vs. whatever)

To: "'Tesla List'" <tesla-at-poodle.pupman-dot-com>
Subject: Re: Barts Coil Desing (was flashing vs. whatever)
From: Tesla List <tesla-at-stic-dot-net>
Date: Sat, 29 Nov 1997 20:35:47 -0600
Approved: tesla-at-stic-dot-net

From: 	Barton B. Anderson[SMTP:mopar-at-mn.uswest-dot-net]
Sent: 	Saturday, November 29, 1997 11:01 PM
To: 	Tesla List
Subject: 	Re: Barts Coil Desing (was flashing vs. whatever)

Bert,

> <SNIP>
> NOW I understand the source of the discrepency! It is essential that
> your tank cap and primary be tuned to your secondary/toroid's operating
> frequency. Now, for maximum power output you may also choose to "size"
> the tank cap to the transformer/ballast power delivery capability.
> However, you must STILL keep the system in tune. BTW, the 14.4 KV term
> in the above equation is already RMS volts, so it does not need to be
> derated by 0.707. This results in a properly "sized" cap value of about
> 0.128 uF to match 10 KVA. However, you can easily run the pig
> intermittently at 20 KVA which will bring you up to the 0.256 uF cap
> previously computed.
>
> However, when you increase the size of the tank cap, you also directly
> increase the amount of energy per "bang". Going from 0.05 uF to 0.256 uF
> basically quintuples the energy available when the gap fires. For
> example, if your gap fires at 16 KV, you'll have 6.4 Joules of energy
> per bang with a 0.05 uF cap, but a whopping 32.7 Joules with the 0.256
> uF cap. All other things being the same, the output voltage of the coil
> would also increase by a factor of about SQRT(5) or 2.24 times...
>

Ok, Now I understand my discrepancy. Thanks! I knew the KVA rating of the pole pig is
rated as "apparent power" due to inductive loading, but I didn't know the output voltage
was rms. I went back through the calcs and came up with 0.128uF (as you did) equating to a
needed reactance af 12.44ohms. This would eventually work out to 16.4 Joules. What do you
think, is this still a bit too "Whopping" for the 12.5" x 33.2" Secondary? I definitely
want to throw as much "umph" at the coil that it can electrically handle, but then I don't
want to kill it (at least on the first couple firings). It might be wise to just go off
the 0.05uF and modify the primary to match Xc?

Let me know your thoughts,
Bart