Re: Geek Caps - Ratings and longevity

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

Original poster: "Crow Leader by way of Terry Fritz <teslalist-at-qwest-dot-net>" <tesla-at-lists.symmetric-dot-net>

Tesla list writes:
>Original poster: "Chris Roberts by way of Terry Fritz 
><teslalist-at-qwest-dot-net>" <quezacotl_14000000000000-at-yahoo-dot-com>
>That might have done it, but no, I'm not running at resonant value. I'm 
>simply using the LTR value on the geek group design chart. Terry took a 
>look at a picture of the caps I sent, and said that they didn't look like 
>they were damaged.
>Here's a picture at:
><http://hot-streamer-dot-com/temp/P7030004.JPG>http://hot-streamer-dot-com/temp/P7 
>030004.JPG
>As you can see, I was worried about the little depressions that circle the 
>middle of each cap. But since Terry thinks they are okay, I'm not one to 
>argue. =D I gave the entire coil a meticulous inspection, along with 
>cleaning off the spark gap electrodes. I removed a huge amout of carbon 
>(or whatever that black stuff is) off of them. Mabye that was the problem. 
>I'll test it again tonight. I hope it works due to it being the fourth. (I 
>hope I don't have to resort to using "normal" fire works) =D

Hybrid (film, foil and metalization) caps are two sections in series. What 
you're seeing in the middle is probably the area where the foil leaded 
sections are connectected by the metallization in the middle, giving the 
cap some sort of self healing ability. I cannot say what's making that area 
collapse on itself.
KEN
>Tesla list <tesla-at-pupman-dot-com> wrote:
>Original poster: "Gerry Reynolds by way of Terry Fritz "
>Hi Chris,
>One thought that crossed my mind is if your setup is running close to
>resonant charging, the xformer may output more than rated voltage.
>Gerry
>----- Original Message -----
>From: "Tesla list"
>To:
>Sent: Thursday, July 03, 2003 6:46 PM
>Subject: Re: Geek Caps - Ratings and longevity
> > Original poster: "Terry Fritz"
> >
> > Hi Chris,
> >
> > At 05:43 PM 7/2/2003 -0700, you wrote:
> > >Hi guys,
> > >It's been about 5 months since I have gotten my 6 inch coil working, and
> > >up until now it has been running perfectly. About a week ago though, the
> > >coil started acting strange. It only makes sparks ab! out half as big as
> > >they should be and it makes a strange hissing noise while running. I
> > >checked the NST and it still works perfectly. I also looked at the spark
> > >gap but nothing seemed out of the ordinary there either. I double checked
> > >the connections everywhere and they were fine also. So I now have to be
> > >suspicious of my MMC again. This time at least, they didn't blow up
> > >immediately so I know I'm doing at least someting right. =D
> > >The MMC is 2 strings of 6 geek caps, giving it a value of .5ufd and a
> > >12000 volt rating. My transformer is a 9kV 120ma NST, so it should be
>fine
> > >with the RMS voltage. However, the peak voltage on the transformer is
> > >somewhere around 12500 right?
> >
> > 9000 x SQRT(2) = 12728 Volts.
> >
> > >I know that these caps are made to tolerate quite above their ratings,
>but
> > >over time could they eventually break ! down from repeatedly running them
> > >above their ratings?
> >
> > Unlikely in very limited use. Geek caps snap at about 3500 volts each.
> >
> >
> > > The outer tape covering the caps are now severly wrinkled and covered
> > > with dents, which may be where they were blasted through.
> >
> > If they are "new" dents and wrinkles, that would be "bad". CD caps
> > normally are a little rugged on the outer surface and they may settle with
> > time. However, if they are obviously "falling apart" during use,
>something
> > is wrong.
> >
> > >Either that, or something else is wrong and the tape may just be
>wrinkled.
> > >Terry, would you mind doing another MMC inspection to see if these things
> > >still work?
> >
> > I can certainly check them here if you want to send them to me. As far as
> > I know they should work fine, but if you think they are the 6x2 string
> > things needs a chec! k we can certainly do it. A nice high resolution
> > picture close up of a "bad" cap sent to me may work just as well too.
> >
> > Cheers,
> >
> > Terry
> > terrellf-at-qwest-dot-net
> >
> >
> >
> > >-Chris
> >
> >
>
>-Chris