fullbr.SSTC air core pri turns?

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

Original poster: "Jan Florian Wagner by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jwagner-at-cc.hut.fi>

Hi,

about determining the initial turns on the primary coil for a full-bridge
with a direct helical TC primary coil drive: is there any constraint that
gives the minimum number of turns on the primary? 

I must say I feel a bit uncomfortable about driving so few uH's at 100kHz
from 640VppAC - I mean, seems like it'd be destined to fry...?  :o)
Especially when the secondary is not in place.

Btw, is there any reason why one shouldn't place the primary inside the
secondary coil former? 
Just thinking that insulation wouldn't be an issue then, and as a bonus
it'd give a bit less stray inductance, AFAIK...?

 - Jan

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