Re: MMC or Maxwell? Which is better?

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

Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>

Hi Kreso,

At 11:58 PM 2/26/2004, you wrote:
>I have 5 coils until now ( ops four i sold a small one on e-bay)! The
>biggest project of mine was a TC with 10 kV 100 mA nst ( original primary
>voltage 220 V i used variac all the way to 260 so i guess there was more
>voltage out ). I like tesal coils i use them all day ( dont worry Terry give
>me a MMC and you will see it blew to the sky). This coil on resonant rise
>produced 4 foot sparks, i had a Gregs filter on the nst. One day i was
>little bit on the mad side and wanted to see what this baybe can do and i
>stretched spark gap ( rq gap ) so wide it would barely fire wow it make 6 +
>foot arcs so i leaved it that way! It worked for some time then i take a
>step up i remowed filter from nst ( resistors eat up some power ) and i
>squezed a centimeter or two more of spark. Pity, safety spark started firing
>so i remowed it to and squezed a little bit more. Then the coil had a 10-15
>LONG runs in 2 days :-). Two days after i turned it on and BOOOOOM my
>Maxwell well you allready know what happened! The i made SW caps and result

I see!!  I think you said before that you were using super strong NSTs.  If 
you resonant that up.  You may get like 80,000 volts!!  You may have gone 
way over voltage on your  Maxwell and that would also explain the fact that 
the dielectrics were full of holes.


>was not so good so i used quick and dirty async gap that burned the nst :-).
>But im lucky my mate works at a local power platn and he just brings me
>pigs, PTs and thast for free ( aint he good ). But i discard them becausee i
>keep only the ones that have a nice voltage and that. Now i got a epoxy
>potted nst rated for 10 kVac and want to make same sucess coil again. I just
>finished repaintin this PT, adding wheels , cables, ballastand and he is
>ready to rock&roll. But im experiencing a big problem there are no caps in
>Croatia so i must order internationaly. And i think using 3 - 4 kVac cap on
>10 kV power supply is BS by my calculation i would need 300 geek group caps
>( 150 nF 2 kvdc ) and that is equal to 900 $ + shipping!!! I learned my
>lesson about stretching the gap and so on but i seriously think and know
>that these caps if used by the chart will fail in a hurry. Il continue to
>thinks so until i see it with my own eyes and that is impossible ( you are
>all too distanced from me ).

I think you need to try to find the true peak voltage of your coils primary 
circuit.  If you are running full resonant and letting it resonate super 
high, the voltage may be very very high!

If you really want to run that high of voltage and have transformers that 
can stand it, then you should use very high voltage capacitors.  Maybe 
100kV!!  If you have tried an MMC before and it failed, the voltage may be 
at least 3 times higher than expected.


>This is my web site click the 1000 W tesla coil! But first click ulaz ( sory
>only Croatian ) :-)
>http://free-kc.htnet.hr/Kreso-Bukvic/
>
>Best regards
>Kreso Bukvic
>
>PS. Terry i would like to see the mmc that is overrated and works :-). Nice
>try.

If you are getting say 40, 50, 60kV...  Then a special MMC could be 
designed to run at that high voltage.  If we knew the voltage, we could 
calculate the MMC and see what it would cost.

Cheers,

         Terry