Re: Commercial caps / MMC

["Robin Copini" <rcopini-at-merlin-dot-net.au> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi Sundog,

 Why can't you use mmc's with a pig? I have a 0.07 to 0.09 uF mmc, (depending
on how many panels I use), that I run with my pig - (270V in = 40500V out,
or in
p - p terms, 57476V). Running for 5 to 6 minutes at a time with a 200bps sync
rotary gives no discernible heating whatsoever, and monster arcs. It's like
everything else, you have to build the mmc to cope with the demands of your
proposed system. At a certain point, mmc cost will be >= commercial cap,
but then
what would you prefer if either cap dies, replace an mmc string, or an entire
cap?

Best Regards,

 Robin in OZ.



Tesla list wrote:

> Original poster: "sundog" <sundog-at-timeship-dot-net>
>
>   Hi all,
>
>  Yup, more from the peanut gallery.  This time, it's *que dramatic music*
> Commercial cap vs MMC
>
>     Why do commercial caps reportedly give better performance than an MMC?
> Aren't they both an extended foil design?  Is it the inductance of the
> wiring in the MMC?  The caps themselves?  I made my strings, and last night
> secured them in parallel to copper-clad PCBs, so I have a block of caps (7
> strings of 11 in a 4x5x12 or so block). DC test charge-discharge worked
> beautiful, and it looks nice too :)   Hopefully lowered the inductance a
> bit, and gave them a lot more conducting area.
>
>   I know that for small coils, MMC's rock.  They beat out commercial caps by
> being "buildable", series/parallel them till you get what you want.  You can
> add and remove capacitance in small amounts to test/tune, replace a failed
> string or individual cap, and not weep ower a blown commercial cap from
> overvoltage. You all *are* using saftey gaps, right? *right!?!*  :)  I have
> to admit, I'd be a lot less scared of blowing an MMC than a commercial cap.
>
>     What are the specs on the Hosfelt caps being used, and the price each?
> Maybe they can be ganged up on a pole-pig?
>
>                                                                         Caio!
>                                                                 Sundog