Re: Geek Caps - Ratings and longevity

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

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/P7030004.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

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