Re: MMC or Maxwell? Which is better?

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

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...