RE: Blown Capacitor!!

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

Original poster: "Garry Freemyer by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Garry-at-NDFC-dot-com>

How well I remember my experience trying to make caps. After about 18
rebuilds of a blown cap, I just sat down and bawled like my heart broke.
Then Terry sent me an EMMC and boy those things work great. I know how
painful it can be to buy commercial caps that don't work. I got a .017 uF
doorknob cap that just produces the whimpiest output. One inch sparks using
a 12/60 NST verses two foot sparks with Terry's cap of .0061 uF and a 12/30
NST. Then I spent $45 for some caps but because I was looking for caps of
.056uF I misread .0056 uF as .056 uF and ended up ordering about 40 caps
that were worthless for what I wanted. I was so careful too, I checked and
rechecked the number of zeros but my mind was bent on decieving me. Terry
graciously bought them up as they would make great filter caps. Then I
bought 50 .033 caps (I think they were .033 uF) for an MMC and I spent three
days putting it together. I wasn't feeling too good so it was a sit for
maybe ten minutes soldering and then laying down. So I get it together and
hook it up and turn it on. Nice 15" maybe longer sparks and I  hadn't even
fine tuned it. After only 6 seconds, I  heard an arching and saw one of the
MMC caps with sparks flying out of it. I replaced the cap, real nervy about
this because I only had 5 spare caps and I turned it on and another flared
out. 

Well, I decided to drop it for a couple of days and recover a bit, but I was
quite unhappy about it. Over the next few days I experienced frying bleeder
resisters and frying caps and despite all I could do the caps continued to
fry till there was nothing left to do but send it to Terry for a post
mortem. Terry mentioned it was the worse MMC failure he had ever heard of.

Turned out the caps were substituted with other caps that had the same specs
but were a type that one end would heat up and blow up at anything near
tesla coil frequencies. In the interest of not causing the loss of Mouser as
a source of caps, I kept my mouth shut and ate the $85 loss. Then Sundog
made a fine MMC for me practically peanuts. I hooked it up last night and
gave it a try. I think it's going to work but I didn't feel up to spending
much time fiddling with it but will do more with it later.

I've had more than my share of flaring secondaries and running discharges
destroying 3 secondaries.

I've become very very gunshy about working with my coil. It seems that every
time I try to make an improvement it turns out to be a loss and waste of
time, so usually, unless I am feeling well, I won't do much with it as I
flinch every time I turn it on expecting it to blow something.

So, for what it's worth, you are not alone in the capacitor woes. I think
MMC's can be built to work for your pig system and work well they do. I wish
you luck in the hobby. A read of your original post shows you know far more
than I do about electronics. I don't even know what a ballast does or what
the word means.

Once you get a working coil, I suggest you hang on to that, and instead of
modifying that drastically, make another afresh. That way if one blows, you
have your other to fall back on. I would do this but I don't have access to
a woodshop and trying to make a tesla coil afresh is too much as all the
stores are usually closed long before I get off work and weekends are just
to precious for me to spend a lot of time running around trying to find bits
and pieces of scrap.

I hope someone can help you. Hmm what's your setup like? 

---
Original poster: "Roderick Maxwell by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <maxz-at-netdoor-dot-com>

 
   I am wiping the tears from my eyes as I type this message. I have fried
the
first capacitor I made for Tesla service......
 
Signed,
A still crying 
Frankenstein's Helper
 
Snip