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DC power - still problems



Original poster: "Chris Swinson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <exxos-at-cps-games.co.uk>

Hi all,

I have been trying to get my NST to DC powered coil running in some sort of
good fashion. I have tried all combinations of coil sizes, reducing and
enlarging primary tank cap.  It still has a good 80-90% power loss
somewhere.  I have now a bank of 8 microwave diodes 15KV 1 amp each between
my NST and smoothing capacitor. These work well and didn't blow like the
last lot.  The dual spark gap idea still works best though I took the
charging gap out and placed the resistors back in there as the contacts on
the gaps were arcing all over and actually shorting the smoothing cap across
the primary, which a nasty bang also ( thank god the cap still lives! ).
The resistors don't work as well, its about 200K and I have some more to
make it 100K though I don't think that it will help much.  I also now having
problems with the spark at one end of the resistors shorting to the case
jumping every resistor and shorting out of the other end, which also shorts
the smoothing cap across the primary. So now have to rearrange them to stop
it arcing across the cases.

I now seem to back stuck at square 1 again on what to try next. I might try
to make sure the NST is charging the smoothing cap up enough as it might be
too much for it. I can parallel another NST across the rectifier to prove if
it is having problems charging it or not. anyone care to speculate before I
try the experiment ?  If anyone has any ideas what else I can try to find
the power loss then that would help!  One thing which might support the NST
problem is it takes about 3 seconds before the power comes up to full. So it
proves that it is having problems charging the smoothing cap up. Though its
hard to say what voltage is on the capacitor, I would assume after 3 seconds
it would be about 15KVDC, Though if the NST is only charging to like 8Kv
then that could be the power loss reason. all good fun :-\

Chris