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Re: [TCML] current limit system and X-rays
X ray generation will not occur until you reach at least 15KV. This
is just simple laws of physics in being able to accelerate electrons
fast enough to be able to produce x rays.
Almost the universal voltage for most X ray work is 40-60 KV.
Using an NST will not work unless you can series them, even a 15KV
transformer will be pushed.
An NST is self regulating in that it produces a high voltage to
strike the discharge in a tube and then as the tubes starts drawing
current, the transformer lowers it voltage accordingly to maintain
the discharge. This is one reason folks remove the shunts so they
have a constant HV to fire a TC (of course you get a LOT more current
too which is what makes coils sing!).
I ran a small Coolidge X ray tube one time using two NST's in series
and got low level X rays, enough to light a fluorescent screen but
not enough to penetrate a finger to see the bones. Of course when I
turned the lights back one, the entire floor of my room was full of
smoke where one transformer arced internally and was having fun
melting and burning the tar!
NOW, NEVER , NEVER, NEVER run a Geissler tube on a NST!
Geissler tubes are like neon tubes, once they are lit, they will draw
as much current as can be supplied. Using a NST will supply to much
current and will overheat the electrodes and destroy the tubes.
Most small Geisslers will run fine on 2KV and larger tubes and small
Crookes tubes will run on a Model T spark coil unless you have
a tube with an X ray vacuum, then you need a spark coil that will
put out at least a 2" spark.
A Model T coil will run most Geissler tubes and is what I use for most tubes.
In addition, a Geissler or Crookes tube needs to run on DC to get the
desired effects as they are polarity sensitive.
Neon sign tubes have a transformer sized to the tube length so as not
to overdrive them.
Frank
At 08:03 AM 9/25/2010, you wrote:
--- On Fri, 9/24/10, amir gh <mamout.72@xxxxxxxxx> wrote:
> can anyone explain if there's anyway to remove current
> limit system in NSTs?
It is possible, but it isn't easy. NST cores are shunted. That is,
small bundles of laminated iron are tucked into the core windows
between the primary and secondary coils. These iron shunts add a
large leakage inductance to the NST, resulting in fairly rigid
current limiting. Removing some or all of the shunts will increase
the output current. To remove the shunts, the NST must be released
from the block of tar or resin it's potted in. This can be a messy,
time-consuming process. Also, the depotting effort sometimes
damages the fragile NST windings. It is do-able though. Many
members of this list have done it successfully. Search for
"depotting" in the WWW.pupman.com archive for more info.
> and can i connect a simple geissler tube to my coil and
> ground to produce
> X-rays?
A Geissler tube is not an X-Ray source. It is a glow discharge tube
filled with rarefied gas--similar to a neon sign. So no, you can't
make X-Rays with it. To make X-Rays, you need a Crookes tube, a
cold cathode X-Ray tube, or some other sort of "hard" vacuum
tube. Assuming you employ a proper tube, NSTs do develop enough
voltage to produce soft X-Rays, according to Wiki:
http://en.wikipedia.org/wiki/Crookes_tube
> tnx for helping again.
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
Cheers,
Greg
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