Re: MMC Caps

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

Original poster: "Christopher Boden by way of Terry Fritz <twftesla-at-qwest-dot-net>" <chrisboden-at-hotmail-dot-com>

John has GOT to have a flaky design. He's been eating caps since the 
beginning (he's been running Geek MMCs for a while) and blowing them. The 
problem is, John's using the same specs to design from as everyone else, and 
he's the only one blowing caps. I *really* think that it's part of the 
design, maybe the spacing of the caps or something else in the coil, and I'd 
love to know exactly what it is, to prevent it from happening in the future 
to John, and other coilers. Any ideas?



>Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
>
>Hi John,
>
>It is unlikely that voltage is damaging the caps but rather current is.
>
>using the equations at:
>
>http://hot-streamer-dot-com/TeslaCoils/MMCInfo/MMCPower4.html
>
>Ecap = 0.3375 Joules
>
>Rcap = 8.49 mOhm
>
>Wo = 95.25 mW
>
>To = 2 C
>
>So the caps should only heat up 2 degrees C. If we look at the RMS current:
>
>Irms = SQRT (Wo / Rcap) = 3.4 amps.  They can take 8 amps...
>
>So I don't know why your 10 string cap would have been failing?  If you
>would want to send me a blown one, I could look at it and maybe figure it 
>out.
>
>Cheers,
>
>	Terry
>
>At 08:35 AM 10/25/2002 -0700, you wrote:
> >I have had experience with those 10 string caps from Geek Group.  I just
> >blew my third capacitor.  It almost always occurs when I am pulling a 
>white
> >streamer to ground, and hence the most current.  Heating is the problem.  
>In
> >my 15kv 90 ma coil, I use two strings of 14, and have had no failures.  
>The
> >single strings seems, like one nomograph I did said, unreliable...  
>Perhaps
> >I ask too much, or as Duck said have tuning problems
> >
> >That said, they are still the best and most supported product you can 
>use.
> >You can get more anecdotal data on them, and real use suggestions than 
>most
> >others!  Run light and tune well if you use one string.
> >
> >John Dyer
> >
> >www.johndyer-dot-com
> >
> >
> >
> >


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