Re: KVA Model 9J

["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 Bob,

On 7 Oct 2001, at 18:03, Tesla list wrote:

> Original poster: "bob golding by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<yubba-at-clara-dot-net>
> 
> hi Malcolm,
>     I am using a variable speed rotary with 8  flying electrodes and 4
> static electrodes configed in two pairs. Max spark length is at about 1500
> R.P.M. I think this equates to about 215 B.P.S. I can never remember the
> formula. This is just before the caps catch fire ;-))

According to quick calc and assuming that V is 8.2kV, BPS = 215, that 
amounts to an average primary power of 500W roughly. I get the same 
sort of figures when I calculate the output of my coil. I *know* I am 
losing a significant amount of power in transformer (heating) and the 
primary surge impedance is not as high as it could be so my gap is 
losing a far bit also. I know that in the case of my coil the 
transformer/cap combination cannot get above 9kV (I can meter the gap 
setting) and my BPS vary from 100 to 200 BPS. My head goes dizzy 
thinking about what might be done with a really efficient supply and 
a wallplug draw of 2kW or so, hence my interest in building an 
efficient switchmode cap charger if I ever get around to it. Marco 
Denicolai's coil performance is indicative and I am sure could do 
better with larger bangs at a lower breakrate and with a bigger top 
terminal. Freau's Law still stands but it is an interesting challenge 
to try and do better.

Regards,
Malcolm