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Re: [TCML] vacuum chamber (OT) was: x-ray transformer for Tesla supply




On Dec 6, 2007, at 8:56 PM, David Rieben wrote:

Hi Rich,

LOL, yes, I figured that you didn't personally own such a vacuum
chamber but I was still amazed at the prospect of a high vacuum
chamber of that magnitude, even in a commercial/industrial setting.
Must have taken a good while to pump it down ;^)

In the late 80's & early 90's I worked at Martin Marietta at the Waterton
complex south of Lakewood Colorado.

The Space Simulation Lab there has what was once the largest space
simulation chamber in the world (bak in the 1970's maybe), although
it has long since been eclipsed by chambers owned by other companies
and gov't labs.

By "space simulation chamber", I mean a big high vacuum chamber which
also has provisions for heating, cooling, and sun simulation (a really
insane quantity of light from xenon arc lamps)

The one at Waterton is a couple of stories tall, and the outside is dotted
with many HUGE cryopumps about two feet in diameter.  (When I worked
there, they were huge Varian diffusion pumps about two feet in diameter)

I don't recall what they used for roughing pumps, but I remember they
had a LOT of them, and despite all that roughing capacity, it still took
many days to pump down to the point where the diffusion pumps could be
turned on.  Someone there once told me the design originally called for
root blower vacuum pumps, but they had been nixed for cost reasons.

Here's a picture of the Phoenix Mars Lander being set up in the chamber,
with the top lid off (removed by gantry crane):

http://www.lockheedmartin.com/data/assets/14528.gif

In addition to the hot/cold shroud, this chamber is also equipped with
a bank of xenon lamps to simulate the light, heat, and approximate
spectrum of the sun, at up to 1.5 solar equivalents (at earth orbital
distance).

David


----- Original Message ----- From: "Rich & DJ" <rdj@xxxxxxxxxxxx>
To: "'Tesla Coil Mailing List'" <tesla@xxxxxxxxxx>
Sent: Thursday, December 06, 2007 6:36 PM
Subject: RE: [TCML] x-ray transformer for Tesla supply


David

Please let me set it straight, I do not have a chamber like that. The
chambers were in the lab complex where I worked.

Hi David!   I used to work with some of the smaller space simulation
(thermal-vacuum) chambers when I worked at the Waterton Complex of Martin-
Marietta, Denver Colorado, in the late 80's.

The 30 foot one was used to
do testing on the Mercury and Gemini spacecraft. The large chamber was in mothballs for several years then reopened. The 18 foot chamber has been in and out of use for years. We had several smaller Hi-Vac ones (some 3' and 5') used for laser communication testing, also 10 and 15 chambers used for high altitude and low temp testing. We had all that and one chicken gun. We
shot chickens, not "at" chickens , they were the projectile.  This is
getting off subject but I had fun.

Rich , from the middle of Missouri

-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of David Rieben
Sent: Thursday, December 06, 2007 2:59 PM
To: Tesla Coil Mailing List
Cc: David Rieben
Subject: Re: [TCML] x-ray transformer for Tesla supply

Hi Rich,

Am I reading that right? 18' and 30' (as in FEET, not INCHES)
diameter vacuum chamber? You're certainly correct in that not
everyone can claim ownership of one of those! :^0

David


----- Original Message ----- From: "Rich & DJ" <rdj@xxxxxxxxxxxx>
To: "'Tesla Coil Mailing List'" <tesla@xxxxxxxxxx>
Sent: Thursday, December 06, 2007 1:51 PM
Subject: RE: [TCML] x-ray transformer for Tesla supply


I agree with David and DC. When I was still working they were testing a 100Kv system and they had to run it in a 18' dia vacuum chamber. Not every one has one of these. It was being moved to a 30' chamber when I retired.
Rich

-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of David Rieben
Sent: Thursday, December 06, 2007 8:59 AM
To: Tesla Coil Mailing List
Cc: David Rieben
Subject: Re: [TCML] x-ray transformer for Tesla supply

Hi DC, all,

Yes, the consensus of the list responses to this question only verifies
my own thoughts on this matter. >100 kV voltages  (or >30 kV volt-
ages, for that matter) would just be too unwieldy for practical use in Tesla primary circuits. I think list member Scot 'Bunnykiller' Dingman has documented the significant voltage standoff difficulties associated just from seriesing (2) 14,400 volt pigs, overdriven with up to 280 volts from a variac, given 'max out' primary circuit voltages of around 33 kV.

David Rieben




----- Original Message ----- From: "resonance" <resonance@xxxxxxxxxxxx >
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Wednesday, December 05, 2007 10:26 AM
Subject: Re: [TCML] x-ray transformer for Tesla supply





For reasons previously discussed on the list this is a bad idea.

The HV requires extra insulation, is problematic, and simple not worth
the

effort. You can achieve sparks up to 80 feet long with a standard 14.4
kV

pole xmfr so why go to higher voltage when it's completely unneccesary?

The caps require lots of current for rapid recharge and an x-ray xmfr
will

not put out 1 to 1.5 Amperes as a pole xmfr can easily do. Plus, a pole xmfr when recased weighs only approx 125 lbs --- compare to a large xray
xmfr at 350 lbs.

Dr. Resonance

Resonance Research Corp.
www.resonanceresearch.com


----- Original Message ----- From: "David Rieben" <drieben@xxxxxxxxxxx >
To: <tesla@xxxxxxxxxx>
Sent: Wednesday, December 05, 2007 8:18 AM
Subject: [TCML] x-ray transformer for Tesla supply


Hi all,

Has anyone on the list successfully used an x-ray transformer
anywhere near its rated output voltage to power a Tesla coil?
(operating at less than 30% of its rated output voltage doesn't
count :^). I have one friend that seems convinced that you could
make a killer coil by running the Tesla primary circuit with over
100 kV but I've always been under the impression that the in-
creased corona losses coupled with the required dramatic increase
in voltage standoff would make such a circuit impractical. Also,
the primary capacitor(s) would have to be able to withstand several
100 kVs although it's rated capacitance could be relatively small.
I'm certainly not trying to demonize x-ray trannies (the old style
60 hz ones, that is) as they absolutely ROCK! With my 150 kVp,
600 mA rated 500-600 lb unit, I can self start arcs at 12" with <
90% of its rated input voltage and 'pull out' 40" power arcs while
pulling over 120 amps through my Green Monster coil's variac and
ballast for 10 minutes at a time and the outer tank surface never
gets the slightest bit warm! Whooppee!! However, I do not believe
these transformers are practical as Tesla coil power sources. Any-
one have any other viewpoints, opposing or supporting? ;^)

David Rieben
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