Re: static "sucker" gap / cap stress

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

Original poster: "Christoph Bohr by way of Terry Fritz <teslalist-at-qwest-dot-net>" <cb-at-luebke-lands.de>

Hi!

Good to find someone who knows the cap, although I think I have seen them on
some coils on the net.
I got mine from alltronics on ebay for 50$, think this was OK. It came
without a label but with the catalog number scratched into the housing.
I thought about buying another one, Tesla Systems Research is offering them
for 73$ I think...wonder if the price is OK.... I initially bought this one
because I was looking for extra security, hearing that they can blow up too
is really disappointing....I have to do most coiling indoors.
At the moment I am transferring roughly 5 KVA through the system, maybe that
is too much for a single cap, but your Idea with the "emergency shut off "
via temperature sensing seems really good and I'll probably build something
like this and with the new information shielding will surely be installed
next time.
Do you think I should buy another cap? or is any other maxwell type better
suitable? or MMC.....at least MMCs seem to be "blow up friendly" for indoor
use.
BTW: I checked my spec paper again and its really has a line in it which
says: max continuos rep rate: 500 PPS....I thought this means 500 shots per
second....but that was probably wrong after what you said....or I might have
the wrong spec sheet.
My sheet can be seen at http://www.luebke-lands.de/media/20P005.pdf  maybe
you can have a llok at it or hand me a link to your paper....

Thanks for your support!

sincerely

Christoph

  ----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, April 24, 2003 7:26 AM
Subject: Re: static "sucker" gap / cap stress


 > Original poster: "Jeremy Scott by way of Terry Fritz
<teslalist-at-qwest-dot-net>" <supertux1-at-yahoo-dot-com>
 >
 > Hi,
 >
 > I use the exact same Maxwell cap in my systems,
 > however I double them up, that is, I use four
 > in a parallel series configuration. .03uf, 70Kv
 > for nice long runs. They are oil filled which makes
 > them nice bombs when they do blow up. I'm thinking
 > of enclosing mine in a nice hardwood box with a fan
 > and maybe one of those CPU temperature display
 > thingys.
 > (Idea: wire a thermistor into relay circuit that
 > controls power to the transformer.)
 >
 > If you look at the spec sheet from Maxwell you'll
 > find that they aren't rated for continuous stress.
 > (They're really designed for the occasional one shot
 > brief discharges: X rays, MRI's and that sorta thing.)
 >
 > The fact that they even last in a tesla circuit is
 > testament to Maxwell quality. I've seen one cut
 > up and there were plenty of black little holes
 > that were the result of a puncture, but the cap
 > fixed itself and before disassembly remained fairly
 > close to it's original value.
 >
 >
 > --- Tesla list <tesla-at-pupman-dot-com> wrote
 >  > Original poster: "Christoph Bohr by way of Terry
 >  > Fritz <teslalist-at-qwest-dot-net>" <cb-at-luebke-lands.de>
 >  >
 >  > Hello everybody.
 >  >
 >  > After experimanting with RSG's I made a little
 >  > excursion back to static gaps.
 >  >
 >  > I built a sucker gap with 2 elektrodes and attached
 >  > an ordinary vacuum
 >  > cleaner to it. ( ordinary design....t-shaped sewer
 >  > tube and 2 copper tubes )
 >  > The results with my current magnifier were
 >  > disappointing as the quenching
 >  > seems not to be too good.
 >  > But with the ordinary 5" setup I got really hot
 >  > white steamers to the
 >  > ceiling space-limited by the walls to 4 feet.
 >  > The power in the arcs must have been really big,
 >  > they almost looked like a
 >  > time-exposure.....only real ;-)
 >  > This mus be due to the high current the MOT-Supply
 >  > can deliver.
 >  > The break rate seemed very high, estimated between
 >  > 400 and 800 bps.
 >  > Only problem that occoured: THe tank cap got warm,
 >  > nit really hot but
 >  > palpable after some 20 second runs at roughly 5KVA (
 >  > no PFC ).
 >  > I use a Maxwell 37667 Type cap, 30nF and 35KV. Is
 >  > this cap to weak for this
 >  > arrangment or do I do something wrong that puts
 >  > stress an the cap.
 >  > Tuning was done at 1KVA before I turned to higher
 >  > power levels....but the
 >  > effect of streamer-loading shouldn't affect the
 >  > tuning too much.
 >  >
 >  > My personal results:
 >  >
 >  > Pros: The sucker gap really performs well and is
 >  > extremely cheap and easy
 >  > to build and seems to be very robust, a good choice
 >  > and a really good
 >  > performer in my                system at least.
 >  >
 >  > Cons: the noise really requiers hearing protection,
 >  > I loosend one of my
 >  > earmuffs for a moment an was really
 >  > shocked.....luckily noone was at home
 >  > at this time.
 >  >            Bad performance with my magnifiers
 >  > although I read about people
 >  > using them succesfully with maggies. I will go for
 >  > high bps RSG with that I
 >  > think, perhaps with
 >  >            sucker gap in series to aid quenching.
 >  >
 >  > Questions to be solved: Cap heating.....is it bad or
 >  > not......dont want to
 >  > destroy it as its my only professional pulse cap.
 >  >
 >  > I hope I don't mess up the list with such "low-level
 >  > posts" but I like to
 >  > share results as sometimes it might be usefull for
 >  > other users,too ...
 >  >
 >  > happy coiling
 >  >
 >  >
 >  > Christoph
 >  >
 >  >
 >
 >
 >
 >