Re: static "sucker" gap / cap stress

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

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
 >
 >