Re: failed cap

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

Original poster: robert & june heidlebaugh <rheidlebaugh-at-desertgate-dot-com> 

Phill.  My students and I have buitl over 12 low d. polyethylene/oil
capacitors with only one failier caused by not enough total thickness. we
use 12 layers of 4mill between plates with no problems. We use clear mineral
oil with no additives. Never tried to use thick poly. others have had
problems with thick poly, More layers less trouble.
     Robert   H
-- 


 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > Date: Mon, 01 Dec 2003 08:02:07 -0700
 > To: tesla-at-pupman-dot-com
 > Subject: Re: failed cap
 > Resent-From: tesla-at-pupman-dot-com
 > Resent-Date: Mon, 1 Dec 2003 08:10:04 -0700
 >
 > Original poster: BunnyKiller <bunikllr-at-bellsouth-dot-net>
 >
 > Hi Phil...
 >
 > hmmmmmm    building ones own cap...    you didnt see my website did you 
??  ;)
 >
 > no matter how hard you try to build your own cap ( and yes Ive built 3 of
 > them and all 3 failed  eventually  the plate cap lasted the longest
 > but it was made from ultra clean PE sheeting 70thou thick with REAL
 > transformer oil...) its best to buy a manufactured cap set    be it an
 > MMC   or Maxwell's systems on Ebay ( best prices Ive seen as to date)
 > ..  I have done rolled caps   plate caps glass caps and wasted alot of $
 > doing so  ( but hey  it was a learning experience and ehhhhhh  yes...
 > it was expensive)
 >
 > definately sounds like you have blown a hole in the dielectric ( PE
 > sheeting)  and the oil is arcing out  ( pull it apart and look for the
 > black holes in the plastic) ...the spark gap at that setting is less of a
 > resistive value than oil in the cap... yes most definately ..   without a
 > secondary in place to "asorb" the energy the cap will arc out first....
 >
 >
 > bite the bullet and buy a set of MMC caps or a set of Maxwells   dont do
 > what I did and waste your money trying to build a home made cap...
 > unless you like learning the hard way   ......
 >
 > Scot D
 >
 >
 > Tesla list wrote:
 >
 >> Original poster: "philip barnes" <luck_phil87-at-hotmail-dot-com>
 >> Hi.
 >> i built a cap with 1.6 mm or 64 mil thick PE dielectric and put the
 >> whole thing in canola oil. It worked great for a while but while i had
 >> just the cap across the nst ,,, with no tesla coil connected.. to test my
 >> new mulitgap sparkgap... the PE between 2 of the plates broke down and
 >> now it blows bubbles and hisses and only produces a spark in the gap if
 >> the gap is 1 mm or 30 mil . Its pretty much had it and must be breaking
 >> down at 1 or 2 thousand volts..IS it more stressfull on a cap with no
 >> tesla coil connected and is it suprising my cap did not last in my
 >> config. The plates are 1.75" clearance from each end and 1" along the
 >> sides. !6 sheets of makes each layer
 >>
 >> Phil
 >>
 >>
 >
 >
 >
 >