Re: MMC or Maxwell? Which is better?

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

Original poster: "Virtualgod" <mike.marcum-at-zoomtown-dot-com> 

I shorted a 35kv .03uF Maxwell I was using to get more current out of a 9/60
nst without unpotting it for a jacob's ladder (had it in series with the
secondary). Had a nice 12" blue/white fireball that sounded like an M80
going off. Scary since I wasn't expecting THAT much charge on it. Still
works, but I don't think I'll do that again.


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, February 26, 2004 10:00 PM
Subject: Re: MMC or Maxwell? Which is better?


 > Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>
 >
 > Hi Ken,
 >
 >
 > >If I set out to collect flowers, I'd have a large collection as well. I'd
 > >bet a large number of the 50 aren't true RF duty rated caps, and would
have
 > >failed because of improper use. I can take the best 12 vold light bulb,
and
 > >it's going to fail if I plug it in an outlet.
 > >
 > >KEN
 >
 > One other thing about MMCs ;-))  They were designed from the ground up for
 > "Tesla coils".  So all the fudge factors and over design was directed
 > toward the common mistakes and mishaps "coilers" make.
 >
 > The huge over voltage and self healing features are the biggest advantage
 > to help MMCs survive those resonant rise events that have killed so many
 > nice commercial caps (Terry filters save the NSTs ;-))
 >
 > The next big advantage are the simple charts for all kinds of NST coils so
 > folks can get exactly what they need (minimal cost) without having to
worry
 > about RMS current, voltage rating, and all kinds of nasty details that
also
 > kill commercial caps.  All the hard work is done.  One just follows the
 > charts and gets the caps and they will work...  When I get Tesla coil caps
 > nowadays, shipping costs and delivery times are the only worry...  I
"know"
 > they will work perfectly fine once I get them...
 >
 > Of course, a commercial cap that is run on a Tesla coil within it's
 > voltage, current, etc. ratings will be fine aside from that defective cap
 > thing years ago...  But aside from the aluminum and plastic, there is also
 > a lot of testing and "work" that has gone into making MMCs "work" for
 > coilers.  In fact, I have never really thought about using them for
 > anything else!  Commercial caps make "you" do all the work, where with
 > MMCs, all the work is already done.
 >
 > Another thing "I" always stress is that MMC have (should have) drain
 > resistors which I think vasty increases safety...  No worries about
 > residual charges on an MMC...
 >
 > Oh yeah!!  MMCs are also sold pretty much at cost.  There are no big
 > markups.  I think I lost a couple bucks on the 4000 I sold and I don't
 > think Chris is using his profits to pay off the Geek Lamborghini :o))
 >
 > I know there will always be people that want to use the commercial caps
and
 > that is fine.  They may be better on really high powered coils.  But I
 > don't think there is a lot of reason for the average coil builder to use
 > anything else unless they can't afford them.  In that case, the Geek
Bucket
 > cap...  But I think there is no doubt that the MMC directly caused the
 > instant extinction of the oil filled poly rolled cap ;-))  Remember them
:o)))
 >
 > An interesting thought, if one put a commercial 25kV 13nF commercial cap
in
 > parallel with a 25kV 13nF MMC*.  How would one blow up the MMC without
 > hurting the commercial cap??  Of course, blowing the commercial cap
without
 > hurting the MMC is easy ;-))
 >
 > Cheers,
 >
 >          Terry
 >
 > *Of course, one answer may be to directly short the thing at 20kV.  But
the
 > inherent inductance and ESR of the MMC will serve to protect
 > it.  Commercial caps are good to about 5 full dead shorts...  But the
 > current in those shorts IS "cool"!!!  If you need those stunning currents,
 > you need commercial caps...  Coilers don't...
 >
 >
 >