Re: Help:

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

Original poster: "Metlicka Marc by way of Terry Fritz <twftesla-at-uswest-dot-net>" <mystuffs-at-orwell-dot-net>

john,
i agree that while most will point you towards the mmc route, there is
still good results to be had with home built, flat plate, bucket caps.
things to be considered from my many, many, many blown flat plate caps
is, (1) make sure there is at least 1" of clearance all around the plate
for dielectric. (2) STAY AWAY FROM MYLAR (3) don't try to build one cell
to carry the full voltage.
these are things i found out the hard way. it just works better to build
several cells that have a 10kv pierce v rating and series\parallel them
up for your C\V rating, just like in mmc's it seems to spread the stress
over a wider area?
i tried building a single cap of 22nf-at-40kv using polypropylene sheet
protectors, after blowing several attempts i went to six cells, 33kv
each, still working to this day, two years now.
though building your own cap will teach you plenty about caps in
general, check your final cost well, terry is offering a very good deal
on poly caps that are more then competitive with all but the cup cap.
i don't think styrene will have any self healing properties, propylene
or some good polyeth. will work. farmtech-dot-com has some hdpe polyethylene
at .1" in 4 x 8' sheets for $22.00 that could be cut into a nice very
high voltage cap if enough plate area is used.
build it right from the first because there's nothing worse then that
loud "glub" that happens after many hours of work.
marc m.

Tesla list wrote:
> 
> Original poster: "John by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<zavisa-at-home-dot-com>
> 
> Besides the obvious phasing issues, is there any reason why I shouldn't
> parallel 3 12kv/30ma NST's?  I'm looking to get over 1kw output and can
> get some NST's cheap right now.
> 
> Also, have any of you used polystyrene for your caps?  It's seems so
> much cheaper to use about 93mils (a sheet of 1/32 and a sheet of 1/16)
> to get the required capacitance to match your transformer than going the
> MMC route?  Any comments??  BTW, in order to meet the .0198 uF
> requirements of matching my xformer, I would use about 58 plates of
> 8"x8" flashing and 2 sheets of 1/16 and 1/32 polystyrene available at
> McMaster Carr for a total of 26 caps in parallel which a capacitance of
> .0198 uF and a voltage rating of 46K.  This is approximating
> polystyrene's dialectric to be 2.2 and about 500 volts/mil.
> 
> This setup would fit in a 5 gallon bucket that could be filled with
> mineral oil or transformer oil (if your lucky enough to have some on
> hand).
> 
> Am I making a stupid mistake here??
> 
> All comments appreciated...Thanks,
> 
> John