Re: moderate sized TC

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

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi Jim,

On 5 Sep 2002, at 17:47, Tesla list wrote:

> Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<jimlux-at-earthlink-dot-net>
> 
> 
> Just fooling around to ballpark things for a multi coil setup.
> 
> Secondary 12" in diameter, 48" winding, #20 wire, spacewound for about 750 
> turns about 37-38 mH, 22 pF Cself
> Topload, 8-12" tube, 48 diameter overall - about 52 pF
> 
> Fres(sec) = about 100 kHz
> 
> Primary, flat spiral, copper pipe, 6-8 turns, 48" OD, 20" ID (i.e. 4" 
> clearance from sec bottom - about 50 uH
> 
> Cpri needs to be about 0.06 uF
> 
> Charged from DC source at 11-15 kV... here's the problem.. I'd like to be 
> able to put around 5kW through the system, and with the fairly small cap, 
> you can only store around 6 Joules/bang, and at 200 bang/sec, that's only 
> 1350 kW.
> 
> Ideas: Use resonant charging, so Vpri can be twice source voltage: say, 
> 20-25 kV, so Ebang = 12-18 J, => 2400-3750 kW
> 
> Could reduce Lpri, which would increase Cpri, and hence Ebang (for the same 
> voltage)but it strikes me, as a gut feel thing, that going to 5-6 turns on 
> the primary is pushing things.
> 
> Suggestions, comments?

I think your proposal would still work quite nicely. What really 
matters in the primary is the inductance/reactance at Fr, NOT the 
number of turns. You'd need a fairly robust gap. You might be nicely 
surprised at how well it will do with 6J at 200BPS. The big topload 
is a plus and the minor topload diameter would be better closer to 
12" rather than 8". 

Regards,
malcolm