The HELL MACHINE works!!! Was Ground tester or Hypot with 1/0 welding cable?

[bobh]

This is in regards to a thumper that followed me home last week. A
thumper is a machine that makes high voltage capacitor discharges of
thousands of joules, to find faults in underground buried cable. Mine
is designed to deliver up to 4,062 joules, or approximately the energy
carried by bullets from a burst of assault rifle fire.

This sounds like the power supply for a very cool rail gun!
http://www.powerlabs.org/railgun.htm

Bob

 

[Ecnerwal]

After he left, I wired up the machine and tried to use it. I made a
primitive spark gap out of two large copper pieces. As it turned out,
it works great. It charges the caps and when it reaches the preset
voltage, it discharges into a spark gap.I only tried it at up to 10
kV.

My recall of time spent in labs where we discharged large capacitor
banks into spark gaps includes X-Ray exposure badges being worn - so you
might want to limit the amount of "amusing sparks" you go around
producing in the open...

The Variac on HV supply AC input is a standard technique for being able
to charge things up slowly and not overload the supply. Standard
operating procedure would be to start with it at zero, crank it up
slowly while monitoring capacitor voltage.

 

[Ignoramus17570]

My recall of time spent in labs where we discharged large capacitor
banks into spark gaps includes X-Ray exposure badges being worn - so you
might want to limit the amount of "amusing sparks" you go around
producing in the open...

The Variac on HV supply AC input is a standard technique for being able
to charge things up slowly and not overload the supply. Standard
operating procedure would be to start with it at zero, crank it up
slowly while monitoring capacitor voltage.

Ecnerwal, that is exactly how it is done on this machine. Good point
about x rays... I will have to read up on it... Energy of electrons
that hit TV screens is 20 kV...

i

 

[Ignoramus17570]

This sounds like the power supply for a very cool rail gun!
http://www.powerlabs.org/railgun.htm

Bob

It would require about 4 times more capacitors... (16 kJ)

i

 

[Michael A. Terrell]

I will try to find an empty coke can, if so, I will try to crush one
tonight. That's relatively easy and requires less energy.

http://members.tripod.com/extreme_skier/cancrusher/

If I make a strongbox from some piece of junk electrical enclosure
lying next to my boat, I will try to shrink coins as well. I will keep
you in mind.

i

What happens if you try to crush a full Coke can? ;-)

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Bert Hickman]

Ecnerwal, that is exactly how it is done on this machine. Good point
about x rays... I will have to read up on it... Energy of electrons
that hit TV screens is 20 kV...

i

As long as your experiments are performed in air at STP, X-rays will not
be a problem. X-ray generation can become a problem when using vacuum
switches, vacuum capacitors, or other high vacuum devices (Klystrons, HV
vacuum tube rectifiers, or hard tube modulators) at high voltages. Film
badges will not be necessary when working with your equipment and
experiments.

Bert
--
-------------------------------------------------------
We specialize in UNIQUE items! Coins shrunk by huge
magnetic fields, our "Captured Lightning" Lichtenberg
Figure sculptures, and Out-of-Print technical Books.
Visit Stoneridge Engineering: http://www.teslamania.com
-------------------------------------------------------

 

[Bruce L. Bergman]

What happens if you try to crush a full Coke can? ;-)

Big Kersploosh! all over. It's been done, and filmed.

--<< Bruce >>--

 

[Bert Hickman]

What happens if you try to crush a full Coke can? ;-)

http://members.iinet.net.au/~pterren/misc1.htm#Can crushing :^)

 

[Ignoramus17570]

As long as your experiments are performed in air at STP, X-rays will not
be a problem. X-ray generation can become a problem when using vacuum
switches, vacuum capacitors, or other high vacuum devices (Klystrons, HV
vacuum tube rectifiers, or hard tube modulators) at high voltages. Film
badges will not be necessary when working with your equipment and
experiments.

Thanks Bert... I exploded a wire today... It was LOUD... The sound was
even sharper than a gunshot. I only have two more of such little steel
wires...

i

 

[Ignoramus17570]

http://members.iinet.net.au/~pterren/misc1.htm#Can crushing :^)

I like the wood burning picture, seems very simple, though wet wood
could explode under a pulsed discharge.

i

 

[Harold and Susan Vordos]

snip-----

As long as your experiments are performed in air at STP, X-rays will not
be a problem. X-ray generation can become a problem when using vacuum
switches, vacuum capacitors, or other high vacuum devices (Klystrons, HV
vacuum tube rectifiers, or hard tube modulators) at high voltages. Film
badges will not be necessary when working with your equipment and
experiments.

Bert,

Could you explain (in terms I might understand) why a vacuum makes a
difference?

TIA

Harold

 

[Bert Hickman]

snip-----



Bert,

Could you explain (in terms I might understand) why a vacuum makes a
difference?

TIA

Harold

Hi Harold,

X-rays occur when charged particles (such as electrons) are accelerated
to high velocities by means of a high voltage electric field and then
rapidly decelerated by colliding with matter.

In air at STP, free electrons tend to frequently collide with air
molecules or combine with neutral oxygen or water vapor molecules to
form negative ions (called electron capture). The average lifetime of
free electrons in air at STP is only about 11 billionths of a second.
Because of collisions and electron capture, free electrons in air cannot
reach velocities sufficient to generate potentially dangerous X-rays,
even in the presence of very high voltages and high electrical fields.

In a vacuum, free electrons can be accelerated by the applied HV field
without colliding with many gas molecules. They can be accelerated to
much higher velocities before eventually colliding with an electrode or
the walls of the container holding the vacuum. Higher electron
velocities translate into higher energy X-rays. Voltages of 10-20 kV and
above can generate "soft" X-rays, and higher voltages will generate
"harder" (more penetrating and more dangerous) X-rays.

Bert
--
-------------------------------------------------------
We specialize in UNIQUE items! Coins shrunk by huge
magnetic fields, our "Captured Lightning" Lichtenberg
Figure sculptures, and Out-of-Print technical Books.
Visit Stoneridge Engineering: http://www.teslamania.com
-------------------------------------------------------

 

[Winfield Hill]

Ignoramus17570 wrote...

The maximum voltage on the scale of this thumper is 25 kV DC.
I have not tried reaching this voltage, or anything close to it,
yesterday, but let's assume that it is a 25 kV machine.

It's likely not, since most machines employ meter ranges that go
20 to 25% past their maximum operating range. I suggest you pull
one of the capacitors and examine its nameplate rating, or get
its part number and call Maxwell (I saw your caps nice orange
color) to find out the rating. You'll not want to operate your
capacitors past say 80% of their rating, if you want them to
enjoy a nice long life, right?

Another suggestion: clean those insulators! Better yet, clean
the whole machine! Dirt and grime may look right, and go well
with a welder, but 20kV gear should be nice and clean, IMHO.

 

[Gunner]

I like the wood burning picture, seems very simple, though wet wood
could explode under a pulsed discharge.

i

Now what does it take to use your supply to generate a very nasty EMP
pulse?

Gunner



"Aren't cats Libertarian? They just want to be left alone.
I think our dog is a Democrat, as he is always looking for a handout"
Unknown Usnet Poster

Heh, heh, I'm pretty sure my dog is a liberal - he has no balls.
Keyton

 

[Harold and Susan Vordos]

snip---

Hi Harold,

X-rays occur when charged particles (such as electrons) are accelerated
to high velocities by means of a high voltage electric field and then
rapidly decelerated by colliding with matter.

In air at STP, free electrons tend to frequently collide with air
molecules or combine with neutral oxygen or water vapor molecules to
form negative ions (called electron capture). The average lifetime of
free electrons in air at STP is only about 11 billionths of a second.
Because of collisions and electron capture, free electrons in air cannot
reach velocities sufficient to generate potentially dangerous X-rays,
even in the presence of very high voltages and high electrical fields.

In a vacuum, free electrons can be accelerated by the applied HV field
without colliding with many gas molecules. They can be accelerated to
much higher velocities before eventually colliding with an electrode or
the walls of the container holding the vacuum. Higher electron
velocities translate into higher energy X-rays. Voltages of 10-20 kV and
above can generate "soft" X-rays, and higher voltages will generate
"harder" (more penetrating and more dangerous) X-rays.

Bert

Thanks, Bert. I even understood it!

Nicely done..

Interesting that air alone changes the behavior.

Harold

 

[Ignoramus17570]

Now what does it take to use your supply to generate a very nasty EMP

pulse?

My guess is that I would need to pass a current pulse through a coil
wound around magnetic core, and placed inthe focus of a paraboloid
(like the reflector found on some electric heaters with exposed
heating coil).

i

 

[Ignoramus24570]

Ignoramus17570 wrote...

It's likely not, since most machines employ meter ranges that go
20 to 25% past their maximum operating range. I suggest you pull
one of the capacitors and examine its nameplate rating, or get
its part number and call Maxwell (I saw your caps nice orange
color) to find out the rating. You'll not want to operate your
capacitors past say 80% of their rating, if you want them to
enjoy a nice long life, right?

Another suggestion: clean those insulators! Better yet, clean
the whole machine! Dirt and grime may look right, and go well
with a welder, but 20kV gear should be nice and clean, IMHO.

Win, I will do as you say. By the way, following your advice, I did
clean the welder relatively thoroughly.

i

 

[Gunner]

Now what does it take to use your supply to generate a very nasty EMP

My guess is that I would need to pass a current pulse through a coil
wound around magnetic core, and placed inthe focus of a paraboloid
(like the reflector found on some electric heaters with exposed
heating coil).

i

See if you can kill a computer or car stereo from a distance.

Gunner



"Aren't cats Libertarian? They just want to be left alone.
I think our dog is a Democrat, as he is always looking for a handout"
Unknown Usnet Poster

Heh, heh, I'm pretty sure my dog is a liberal - he has no balls.
Keyton

 

[Ignoramus24570]

See if you can kill a computer or car stereo from a distance.

That's highly illegal, plus I do not have spare computers of car
stereos...

i

 

[Gunner]

That's highly illegal, plus I do not have spare computers of car
stereos...

i

No (THUMP THUMP) neighbor (Thump THUMP) kids (Thump Thump) in the
(THUMP THUMPTHUMPTHUMP) neighborhood?

Shrug..just a thought. Though I didnt think it was illegal to kill
your own computer...or how anyone could prove you silenced a (thump
thump) car stereo from a distanc.

Gunner



"Aren't cats Libertarian? They just want to be left alone.
I think our dog is a Democrat, as he is always looking for a handout"
Unknown Usnet Poster

Heh, heh, I'm pretty sure my dog is a liberal - he has no balls.
Keyton