Re: MMC for 4 pack MOT supply

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

Original poster: "Finn Hammer by way of Terry Fritz <twftesla-at-qwest-dot-net>" <f-h-at-c.dk>

Andy, all!

I have been running my 8" by 24" coil with both a centertapped,
oilsubmerged 4 stack of MOT`s, as well as an for reference coustum wound
mini pig wound to the same voltage.
This machine is using 20 strings of 10 pcs of Phillips 386 pulsecaps,
1600 VDC; 56 nF. total 112 nF.

The small value of each individual cap provides several strings, and I
like that. The coil delivers 5 feet streamers effortlessly.

Whay you might be interested in, is some experiments that I performed
back 2 years ago, when the MMC consept was still in it`s youth.

I started with 2 MOT`s, and 1 of the above mentioned cap`s in parallel,
they lasted 1/2 minute.
Next: 4 caps, 2by2, they lasted 15 minutes, burnt up 2 of those.
Disection showed big holes blasted in the center turns of
foil/dielectric, typical of heat buildup, due to excessive current, and
associated heat build up.

At this time I built a 4 by 8 cap, which went into 2 years of service at
a Frankenstein Stage built in an exebition at the danish electricity
museum, about the Romantic period, and electricity. That cap is still in
service.
I also built the logic intermediate, a 3 by 6 cap, which has been my
workhorse, serving me with sparks from the 4" by 14" coil that was
powered by the twin stack. This cap is also in service.

I don`t know for sure, how the Cornell Dublier caps hold up, when they
are strung up in comparatively few strings.

Cheers, Finn Hammer

Tesla list wrote:
> 
> Original poster: "Andy Cobaugh by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <kb3ewy-at-rcn-dot-com>
> 
> All,
> I would like some advice on my idea about a capacitor for a 4 pack MOT
supply.
> I would like to make 4 strings of 6 Geek group caps for a voltage rating of
> 12KV and 100nF.  My question is will the capacitors take the current and the
> power from the MOTs or do I have to build a capacitor for this one.  If I did
> this it would be easy to go to 2 strings of 12 for my 15/60 NST supply.
Also,
> will the 6000VA or so this psu will be supplying be overpowering my 4" x 20"
> secondary?  Can high voltage side capacitve ballasting reduce the power
> somewhat? (I did this with 2 series MOTs and could plug them directly into a
> 15A outlet, 1 MO cap on each "leg").  Any and all help is greatly
appreciated.
> 
> Cheers,
> 
> Andy C.
> Internet Homepage:
> <http://users.rcn-dot-com/tcobaugh/>http://users.rcn-dot-com/tcobaugh/
> Ham Radio Call: KB3EWY
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