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Re: Further MMC woes.



gary,
i'm not going to try to tell you that your not justified in your disgust
at the mmc failure, i just want you to know your not alone in the costly
failure boat. as an example, i'll tell you about my "learning curve" in
the construction of a flat plate cap for my pt system. i needed a cap to
take the 30kv from my pt, at the time i was using a variac for voltage
adjustment and therefore current limiting (this was before i knew about
the list), i tried polyeth. sheeting at first, it seemed that i couldn't
find pure, virgin poly sheeting and was trying plastic that had
inclusions in it. i built caps with .040" of sheeting in-between the
plates and after cutting, zip tying together, and putting in oil the
cell, it blew in short order. this repeated a couple times before i came
up with using polypropylene sheet protectors instead, in using the sheet
protectors, i tried to build one capacitor cell that would do the job in
itself, this also blew in short order and was pulled from the oil to be
rebuilt many times.
by now i could have gotten rich from stock in the mineral oil companies,
i was probably ten gallons into it. then i decided to go the money and
buy enough sheet protectors to build six individual cells to be, three
seriesed and paralleled to three more, i put each bank of three in a
bucket  and then paralleled the two buckets together. this finally gave
me a cap that each cell held a rating of 33nf-at-30kv so with three
seriesed, each bucket held a 12nf-at-90kv cap.
all in all, i probably wasted $200+ and about a month of time to end up
with a final cap that cost $90 more dollars and a rating of 24nf-at- 90kv.
now i have a good set of bucket caps that i can be sure will take
whatever i throw at them, at this time, and still use them once in a
while, to this day. my mistake was trying to build one to do all the
work?
the moral to my story is that i feel for your hurt, i was ready to give
up on using my pt because i just couldn't get a cap that would take it
and every time a new try would blow, i almost would cry.
i think the problems with your mmc will be determined and all may
benefit so try to remember that there are others out here that are not
blessed to have everything work out the first, second or tenth time, but
your troubles could help others? it doesn't bring back the money lost,
but it sometimes helps to remember this? i always hoped my knowledge
gained could be passed on to others, but with the advent of mmc's, the
learning about capacitors was for me only it seems.
compassionately,    marc