Van de Graaff device and common sense in physics ...

Van de Graaff device and common sense in physics ....

The working principle for Van de Graaff device is analyzed again in this material:

http://elkadot.com/index.php/en/books/electromagnetism/van-de-graaff-device

The actual explanation contradicts all we know about triboelectricity. It is impossible for the same belt to come into contact with two identical rollers and to deliver a positive charge to a sphere and a negative charge to another sphere. Either triboelectric series, either actual explanation for VDG device is nonsense.

More than that, it is impossible to transfer a same type of charge from a body carrying a smaller charge to another body carrying a greater charge. Therefore the maximum charge accumulated on spheres should be equal with amount of charge generated in contact or friction process. Actual physics it is not able to explain how is possible to accumulate a huge charge on the sphere during belt rotation in contradiction with all known concepts of physics.

The Van de Graaff device with a charge injection system does not need any comment. Why don't we inject directly the charge over the sphere and arrive to billions of volts and it is preferred to inject it on a belt and carried further by the belt.....?

The old material is still available as pdf file on the site and in fact the new material is only a refined presentation of it.

Best regards,

Sorin Cosofret

 

[whit3rd]

On Sunday, May 17, 2015 at 2:55:09 AM UTC-7, sorin.c...@elkadot.com wrote:

Van de Graaff device and common sense in physics ....

> ... it is impossible to transfer a same type of charge from a body carrying a smaller charge to another body carrying a greater charge. Therefore the maximum charge accumulated on spheres should be equal with amount of charge generated in contact or friction process.

That's false. Charge moves according to local fields, and the fields inside
a hollow conductor are NOT CAUSED BY CHARGES THAT ARE FREE TO FLOW
IN THAT CONDUCTOR. It takes some energy to add charge to the van de Graaff sphere,
but it doesn't depend on 'smaller charge' or 'greater charge' conditions.

 

[George Herold]

On Sunday, May 17, 2015 at 5:55:09 AM UTC-4, sorin.c...@elkadot.com wrote:

Van de Graaff device and common sense in physics ....

The working principle for Van de Graaff device is analyzed again in this material:

http://elkadot.com/index.php/en/books/electromagnetism/van-de-graaff-device

I don't like figure 1.) I don't think there are negative charges going
down the belt on the back side. Have you ever played with a VdG?
I always liked how you can hear the motor work harder as the
top sphere becomes charged.
(I assume you know Gauss's law about excess charges moving to the outside
of a conductor.)

George H.

The actual explanation contradicts all we know about triboelectricity. It is impossible for the same belt to come into contact with two identical rollers and to deliver a positive charge to a sphere and a negative charge to another sphere. Either triboelectric series, either actual explanation for VDG device is nonsense.

More than that, it is impossible to transfer a same type of charge from a body carrying a smaller charge to another body carrying a greater charge. Therefore the maximum charge accumulated on spheres should be equal with amount of charge generated in contact or friction process. Actual physics it is not able to explain how is possible to accumulate a huge charge on the sphere during belt rotation in contradiction with all known concepts of physics.

The Van de Graaff device with a charge injection system does not need any comment. Why don't we inject directly the charge over the sphere and arrive to billions of volts and it is preferred to inject it on a belt and carried further by the belt.....?

The old material is still available as pdf file on the site and in fact the new material is only a refined presentation of it.

Best regards,

Sorin Cosofret

 

[default]

On Sun, 17 May 2015 02:55:06 -0700 (PDT), sorin.cosofret@elkadot.com
wrote:

Van de Graaff device and common sense in physics ....

The working principle for Van de Graaff device is analyzed again in this material:

http://elkadot.com/index.php/en/books/electromagnetism/van-de-graaff-device

The actual explanation contradicts all we know about triboelectricity. It is impossible for the same belt to come into contact with two identical rollers and to deliver a positive charge to a sphere and a negative charge to another sphere. Either triboelectric series, either actual explanation for VDG device is nonsense.

More than that, it is impossible to transfer a same type of charge from a body carrying a smaller charge to another body carrying a greater charge. Therefore the maximum charge accumulated on spheres should be equal with amount of charge generated in contact or friction process. Actual physics it is not able to explain how is possible to accumulate a huge charge on the sphere during belt rotation in contradiction with all known concepts of physics.

The Van de Graaff device with a charge injection system does not need any comment. Why don't we inject directly the charge over the sphere and arrive to billions of volts and it is preferred to inject it on a belt and carried further by the belt.....?

The old material is still available as pdf file on the site and in fact the new material is only a refined presentation of it.

Philosophically.. Never argue against empirical results.
That's just plain silly.

Find a theory that fits the empirical results then test your new
theory.

You will either learn to believe what is already written, or become
The Guy that Toppled the World of Physics. Either way, you win.

 

[Cydrome Leader]

George Herold <gherold@teachspin.com> wrote:

On Sunday, May 17, 2015 at 5:55:09 AM UTC-4, sorin.c...@elkadot.com wrote:
Van de Graaff device and common sense in physics ....

The working principle for Van de Graaff device is analyzed again in this material:

http://elkadot.com/index.php/en/books/electromagnetism/van-de-graaff-device

I don't like figure 1.) I don't think there are negative charges going
down the belt on the back side. Have you ever played with a VdG?
I always liked how you can hear the motor work harder as the
top sphere becomes charged.

Not my van degraff generator. I have an over-balance wheel running it,
nonstop for years now. I'd tell you more, but the oil companies won't let
me.

 

[George Herold]

On Wednesday, May 20, 2015 at 6:15:41 PM UTC-4, Cydrome Leader wrote:

George Herold <gherold@teachspin.com> wrote:
On Sunday, May 17, 2015 at 5:55:09 AM UTC-4, sorin.c...@elkadot.com wrote:
Van de Graaff device and common sense in physics ....

The working principle for Van de Graaff device is analyzed again in this material:

http://elkadot.com/index.php/en/books/electromagnetism/van-de-graaff-device

I don't like figure 1.) I don't think there are negative charges going
down the belt on the back side. Have you ever played with a VdG?
I always liked how you can hear the motor work harder as the
top sphere becomes charged.

Not my van degraff generator. I have an over-balance wheel running it,
nonstop for years now. I'd tell you more, but the oil companies won't let
me.
OK that's too bad, (you can't talk) some sort of patent involved?

Or have you been bought out (hush money) along with the 100 mpg carburetor. :^)

George H.

 

[George Herold]

On Thursday, May 21, 2015 at 12:47:21 PM UTC-4, et...@whidbey.com wrote:

On Wed, 20 May 2015 22:15:39 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

George Herold <gherold@teachspin.com> wrote:
On Sunday, May 17, 2015 at 5:55:09 AM UTC-4, sorin.c...@elkadot.com wrote:
Van de Graaff device and common sense in physics ....

The working principle for Van de Graaff device is analyzed again in this material:

http://elkadot.com/index.php/en/books/electromagnetism/van-de-graaff-device

I don't like figure 1.) I don't think there are negative charges going
down the belt on the back side. Have you ever played with a VdG?
I always liked how you can hear the motor work harder as the
top sphere becomes charged.

Not my van degraff generator. I have an over-balance wheel running it,
nonstop for years now. I'd tell you more, but the oil companies won't let
me.
I built an over center wheel for my bike. It works very well going
downhill but I still haven't been able to get it to climb even the
slightest uphill grade. I think the problem is that it is too small
diameter. So I am going to try gearing it down.
Eric

Oh.. It's a joke. (I'm fairly gullible... obviously.)

George H.

 

On Wed, 20 May 2015 22:15:39 +0000 (UTC), Cydrome Leader
<presence@MUNGEpanix.com> wrote:

George Herold <gherold@teachspin.com> wrote:
On Sunday, May 17, 2015 at 5:55:09 AM UTC-4, sorin.c...@elkadot.com wrote:
Van de Graaff device and common sense in physics ....

The working principle for Van de Graaff device is analyzed again in this material:

http://elkadot.com/index.php/en/books/electromagnetism/van-de-graaff-device

I don't like figure 1.) I don't think there are negative charges going
down the belt on the back side. Have you ever played with a VdG?
I always liked how you can hear the motor work harder as the
top sphere becomes charged.

Not my van degraff generator. I have an over-balance wheel running it,
nonstop for years now. I'd tell you more, but the oil companies won't let
me.

I built an over center wheel for my bike. It works very well going
downhill but I still haven't been able to get it to climb even the
slightest uphill grade. I think the problem is that it is too small
diameter. So I am going to try gearing it down.
Eric

 

[John Larkin]

On Thu, 21 May 2015 12:09:34 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

On Thursday, May 21, 2015 at 12:47:21 PM UTC-4, et...@whidbey.com wrote:
On Wed, 20 May 2015 22:15:39 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

George Herold <gherold@teachspin.com> wrote:
On Sunday, May 17, 2015 at 5:55:09 AM UTC-4, sorin.c...@elkadot.com wrote:
Van de Graaff device and common sense in physics ....

The working principle for Van de Graaff device is analyzed again in this material:

http://elkadot.com/index.php/en/books/electromagnetism/van-de-graaff-device

I don't like figure 1.) I don't think there are negative charges going
down the belt on the back side. Have you ever played with a VdG?
I always liked how you can hear the motor work harder as the
top sphere becomes charged.

Not my van degraff generator. I have an over-balance wheel running it,
nonstop for years now. I'd tell you more, but the oil companies won't let
me.
I built an over center wheel for my bike. It works very well going
downhill but I still haven't been able to get it to climb even the
slightest uphill grade. I think the problem is that it is too small
diameter. So I am going to try gearing it down.
Eric

Oh.. It's a joke. (I'm fairly gullible... obviously.)

George H.

I have a guaranteed cure for gullibility. If you want to be cured,
send me a check for $5000.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[John Fields]

On Thu, 21 May 2015 13:51:48 -0700, John Larkin
<jlarkin@highlandtechnology.com> wrote:

I have a guaranteed cure for gullibility. If you want to be cured,
send me a check for $5000.

---
Heh...

"Gullible" isn't even in the dictionary.

John Fields

 

[George Herold]

On Thursday, May 21, 2015 at 4:51:53 PM UTC-4, John Larkin wrote:

On Thu, 21 May 2015 12:09:34 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:

On Thursday, May 21, 2015 at 12:47:21 PM UTC-4, et...@whidbey.com wrote:
On Wed, 20 May 2015 22:15:39 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

George Herold <gherold@teachspin.com> wrote:
On Sunday, May 17, 2015 at 5:55:09 AM UTC-4, sorin.c...@elkadot.com wrote:
Van de Graaff device and common sense in physics ....

The working principle for Van de Graaff device is analyzed again in this material:

http://elkadot.com/index.php/en/books/electromagnetism/van-de-graaff-device

I don't like figure 1.) I don't think there are negative charges going
down the belt on the back side. Have you ever played with a VdG?
I always liked how you can hear the motor work harder as the
top sphere becomes charged.

Not my van degraff generator. I have an over-balance wheel running it,
nonstop for years now. I'd tell you more, but the oil companies won't let
me.
I built an over center wheel for my bike. It works very well going
downhill but I still haven't been able to get it to climb even the
slightest uphill grade. I think the problem is that it is too small
diameter. So I am going to try gearing it down.
Eric

Oh.. It's a joke. (I'm fairly gullible... obviously.)

George H.

I have a guaranteed cure for gullibility. If you want to be cured,
send me a check for $5000.

Do you think that will work? I'm guessing that if
I sent you a check for $5k, that you are too nice a guy
and wouldn't cash it. And then where would I be?

George H.

--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[M Philbrook]

In article <dddb32aa-6058-4c53-8e89-ccb4955cada0@googlegroups.com>,
gherold@teachspin.com says...

On Thursday, May 21, 2015 at 4:51:53 PM UTC-4, John Larkin wrote:
On Thu, 21 May 2015 12:09:34 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:

On Thursday, May 21, 2015 at 12:47:21 PM UTC-4, et...@whidbey.com wrote:
On Wed, 20 May 2015 22:15:39 +0000 (UTC), Cydrome Leader
presence@MUNGEpanix.com> wrote:

George Herold <gherold@teachspin.com> wrote:
On Sunday, May 17, 2015 at 5:55:09 AM UTC-4, sorin.c...@elkadot.com wrote:
Van de Graaff device and common sense in physics ....

The working principle for Van de Graaff device is analyzed again in this material:

http://elkadot.com/index.php/en/books/electromagnetism/van-de-graaff-device

I don't like figure 1.) I don't think there are negative charges going
down the belt on the back side. Have you ever played with a VdG?
I always liked how you can hear the motor work harder as the
top sphere becomes charged.

Not my van degraff generator. I have an over-balance wheel running it,
nonstop for years now. I'd tell you more, but the oil companies won't let
me.
I built an over center wheel for my bike. It works very well going
downhill but I still haven't been able to get it to climb even the
slightest uphill grade. I think the problem is that it is too small
diameter. So I am going to try gearing it down.
Eric

Oh.. It's a joke. (I'm fairly gullible... obviously.)

George H.

I have a guaranteed cure for gullibility. If you want to be cured,
send me a check for $5000.

Do you think that will work? I'm guessing that if
I sent you a check for $5k, that you are too nice a guy
and wouldn't cash it. And then where would I be?

George H.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

you can always send it to me if you wish

Jamie

 

[wbeaty]

More than that, it is impossible to transfer a same type of
charge from a body carrying a smaller charge to another body
carrying a greater charge.

False.

"Faraday's Ice-pail" effect allows all the charge on a small conductive object to migrate to the outside of a large conductive bucket.

http://amasci.com/emotor/icepail.html

VDG machines are based on Faraday's Ice-Pail. Really that's the whole point of the VDG. Otherwise they would be no different than a long rubber version of Toepler/Holtz automatic electrophorus.

Why don't we inject directly the charge over the
sphere and arrive to billions of volts and it is
preferred to inject it on a belt

If we inject 5KV onto the belt, then because of the Faraday's Ice Pail process, the voltage on the hollow sphere rises constantly to infinity (given infinite charge-time and perfectly insulated hollow sphere!) Or more practical: a classroom desktop version easily produces 300,000VDC using a felt-covered roller and a belt made from thin balloon rubber. No, the belt and roller do not produce 1/3 Megavolt. The hollow sphere is the cause of that immense potential.

To disable this process, remove the hollow sphere to an insulating stand, and use a wire to connect the outside of the sphere to the upper comb, so charge on the belt is applied to the *outside* of the hollow sphere. It will produce a few kilovolts, rather than the 1/3 Megavolt.

VandeGraaff machine FAQ: http://amasci.com/emotor/vdgdesc.html

Separate topic: to double the charging current, so that opposite charges are carried by two halves of the belt, simply use an isolated metal roller up inside the hollow sphere. This electrically-floating roller will acquire the same charge as that on the belt. This charged roller then will produce an e-field which drives excess charge into the upper comb, leaving the descending half of the belt with a charge opposite to the ascending half of the belt.

Finally... to deeply understand VDG belt operation, always connect the lower comb to ground, and use rollers made of metal, and connect the lower roller to a source of DC high voltage. In theory, this roller-charging power supply provides zero current, an "inductor plate" only, since the belt-charging current all passes through the lower comb's ground wire. Modern classroom VDG machines work this, way, but rather than an expensive DC power supply which provides nanoamperes at kilovolts, they just use a felt roller or a teflon roller. Then the adjacent comb works by electrostatic induction, i.e. the whole comb/roller assembly becomes an "automated Electrophorus" where the roller is the "Electrophorus wax cake."

 

[John Larkin]

On Sun, 24 May 2015 17:39:07 -0700 (PDT), wbeaty <billb@eskimo.com>
wrote:

More than that, it is impossible to transfer a same type of
charge from a body carrying a smaller charge to another body
carrying a greater charge.

False.

"Faraday's Ice-pail" effect allows all the charge on a small conductive object to migrate to the outside of a large conductive bucket.

http://amasci.com/emotor/icepail.html

VDG machines are based on Faraday's Ice-Pail. Really that's the whole point of the VDG. Otherwise they would be no different than a long rubber version of Toepler/Holtz automatic electrophorus.


Why don't we inject directly the charge over the
sphere and arrive to billions of volts and it is
preferred to inject it on a belt

If we inject 5KV onto the belt, then because of the Faraday's Ice Pail process, the voltage on the hollow sphere rises constantly to infinity (given infinite charge-time and perfectly insulated hollow sphere!) Or more practical: a classroom desktop version easily produces 300,000VDC using a felt-covered roller and a belt made from thin balloon rubber. No, the belt and roller do not produce 1/3 Megavolt. The hollow sphere is the cause of that immense potential.

To disable this process, remove the hollow sphere to an insulating stand, and use a wire to connect the outside of the sphere to the upper comb, so charge on the belt is applied to the *outside* of the hollow sphere. It will produce a few kilovolts, rather than the 1/3 Megavolt.

VandeGraaff machine FAQ: http://amasci.com/emotor/vdgdesc.html

Separate topic: to double the charging current, so that opposite charges are carried by two halves of the belt, simply use an isolated metal roller up inside the hollow sphere. This electrically-floating roller will acquire the same charge as that on the belt. This charged roller then will produce an e-field which drives excess charge into the upper comb, leaving the descending half of the belt with a charge opposite to the ascending half of the belt.

Finally... to deeply understand VDG belt operation, always connect the lower comb to ground, and use rollers made of metal, and connect the lower roller to a source of DC high voltage. In theory, this roller-charging power supply provides zero current, an "inductor plate" only, since the belt-charging current all passes through the lower comb's ground wire. Modern classroom VDG machines work this, way, but rather than an expensive DC power supply which provides nanoamperes at kilovolts, they just use a felt roller or a teflon roller. Then the adjacent comb works by electrostatic induction, i.e. the whole comb/roller assembly becomes an "automated Electrophorus" where the roller is the "Electrophorus wax cake."

Suppose the belt was a chain of capacitors. At the bottom, charge each
cap as much as you can. As the belt spins, the charged caps are
lifted, in series, up to the top.

Less voltage than the VDG maybe, but a lot more charge.

 

[whit3rd]

On Sunday, May 24, 2015 at 8:04:10 PM UTC-7, John Larkin wrote:

On Sun, 24 May 2015 17:39:07 -0700 (PDT), wbeaty <billb@eskimo.com
wrote:

More than that, it is impossible to transfer a same type of
charge from a body carrying a smaller charge to another body
carrying a greater charge.

False.

"Faraday's Ice-pail" effect allows all the charge on a small conductive object to migrate to the outside of a large conductive bucket.

Suppose the belt was a chain of capacitors. At the bottom, charge each
cap as much as you can. As the belt spins, the charged caps are
lifted, in series, up to the top.

That's not a van de Graaff, though, it's a pelletron. It has a link belt instead
of a continuous belt.

<https://jrm.phys.ksu.edu/scripts/beam-gallery.pl?Pelletron>

 

[John Larkin]

On Sun, 24 May 2015 22:46:29 -0700 (PDT), whit3rd <whit3rd@gmail.com>
wrote:

On Sunday, May 24, 2015 at 8:04:10 PM UTC-7, John Larkin wrote:
On Sun, 24 May 2015 17:39:07 -0700 (PDT), wbeaty <billb@eskimo.com
wrote:

More than that, it is impossible to transfer a same type of
charge from a body carrying a smaller charge to another body
carrying a greater charge.

False.

"Faraday's Ice-pail" effect allows all the charge on a small conductive object to migrate to the outside of a large conductive bucket.

Suppose the belt was a chain of capacitors. At the bottom, charge each
cap as much as you can. As the belt spins, the charged caps are
lifted, in series, up to the top.

That's not a van de Graaff, though, it's a pelletron. It has a link belt instead
of a continuous belt.

https://jrm.phys.ksu.edu/scripts/beam-gallery.pl?Pelletron

The pelletron has the same dynamics as the VDG. The series string of
capacitors would be different.

Imagine one of those old color TV capacitors, a flat hockey-puck sort
of epoxy thing with terminals on either side.

Charge one to 30 KV.

Now charge another one to 30 KV and slip it under the first one.

Continue building a tower, 30 KV at a time.


--

John Larkin Highland Technology, Inc
picosecond timing laser drivers and controllers

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[whit3rd]

On Tuesday, May 26, 2015 at 6:27:34 PM UTC-7, John Larkin wrote:

On Sun, 24 May 2015 22:46:29 -0700 (PDT), whit3rd <whit3rd@gmail.com
wrote:

... not a van de Graaff, though, it's a pelletron. It has a link belt instead
of a continuous belt.

https://jrm.phys.ksu.edu/scripts/beam-gallery.pl?Pelletron

The pelletron has the same dynamics as the VDG. The series string of
capacitors would be different.

Imagine one of those old color TV capacitors, a flat hockey-puck sort
of epoxy thing with terminals on either side.

Charge one to 30 KV.

Now charge another one to 30 KV and slip it under the first one.

Ack! That's more like a Marx generator.
Look carefully at the pelletron diagram: the pellets aren't charged from
HV supplies, they're induced ( by HV electrodes that never touch, nor
draw current); the current all comes through the drive drum, and ammeter "A".

<https://jrm.phys.ksu.edu/Resource/Pics/Pelletron/28-ELEC_SCHEMATIC.jpg>

Unlike a Marx generator, the voltage achieved isn't limited by the number of
elements in a stack.

The top is interesting, there's a symmetric charge induced in the opposite sign
and carried down the returning chain.

 

[Jasen Betts]

On 2015-05-27, John Larkin <jlarkin@highlandtechnology.com> wrote:

On Sun, 24 May 2015 22:46:29 -0700 (PDT), whit3rd <whit3rd@gmail.com
wrote:

On Sunday, May 24, 2015 at 8:04:10 PM UTC-7, John Larkin wrote:
On Sun, 24 May 2015 17:39:07 -0700 (PDT), wbeaty <billb@eskimo.com
wrote:

More than that, it is impossible to transfer a same type of
charge from a body carrying a smaller charge to another body
carrying a greater charge.

False.

"Faraday's Ice-pail" effect allows all the charge on a small conductive object to migrate to the outside of a large conductive bucket.

Suppose the belt was a chain of capacitors. At the bottom, charge each
cap as much as you can. As the belt spins, the charged caps are
lifted, in series, up to the top.

That's not a van de Graaff, though, it's a pelletron. It has a link belt instead
of a continuous belt.

https://jrm.phys.ksu.edu/scripts/beam-gallery.pl?Pelletron

The pelletron has the same dynamics as the VDG. The series string of
capacitors would be different.

charged bits separated by dielectric, seems the same to me

Imagine one of those old color TV capacitors, a flat hockey-puck sort
of epoxy thing with terminals on either side.

Charge one to 30 KV.

Now charge another one to 30 KV and slip it under the first one.

Continue building a tower, 30 KV at a time.

I giess the difference is that a pelletron doesn't charge the pellets
by connecting a voltage source across pellets

the ticky bit would be stopping the charge from coming back down the
the descending chaig.


--
umop apisdn

 

[George Herold]

On Wednesday, May 27, 2015 at 2:51:54 AM UTC-4, whit3rd wrote:

On Tuesday, May 26, 2015 at 6:27:34 PM UTC-7, John Larkin wrote:
On Sun, 24 May 2015 22:46:29 -0700 (PDT), whit3rd <whit3rd@gmail.com
wrote:

... not a van de Graaff, though, it's a pelletron. It has a link belt instead
of a continuous belt.

https://jrm.phys.ksu.edu/scripts/beam-gallery.pl?Pelletron

The pelletron has the same dynamics as the VDG. The series string of
capacitors would be different.

Imagine one of those old color TV capacitors, a flat hockey-puck sort
of epoxy thing with terminals on either side.

Charge one to 30 KV.

Now charge another one to 30 KV and slip it under the first one.

Ack! That's more like a Marx generator.
Look carefully at the pelletron diagram: the pellets aren't charged from
HV supplies, they're induced ( by HV electrodes that never touch, nor
draw current); the current all comes through the drive drum, and ammeter "A".

https://jrm.phys.ksu.edu/Resource/Pics/Pelletron/28-ELEC_SCHEMATIC.jpg

Unlike a Marx generator, the voltage achieved isn't limited by the number of
elements in a stack.

The top is interesting, there's a symmetric charge induced in the opposite sign
and carried down the returning chain.

Hmm OK so there is negative charge going down the belt too?
This is a nice pic.
http://www.pelletron.com/charging.htm

I don't quite see how the induction works at the top.

George H.

 

[John Larkin]

On Tue, 26 May 2015 23:51:50 -0700 (PDT), whit3rd <whit3rd@gmail.com>
wrote:

On Tuesday, May 26, 2015 at 6:27:34 PM UTC-7, John Larkin wrote:
On Sun, 24 May 2015 22:46:29 -0700 (PDT), whit3rd <whit3rd@gmail.com
wrote:

... not a van de Graaff, though, it's a pelletron. It has a link belt instead
of a continuous belt.

https://jrm.phys.ksu.edu/scripts/beam-gallery.pl?Pelletron

The pelletron has the same dynamics as the VDG. The series string of
capacitors would be different.

Imagine one of those old color TV capacitors, a flat hockey-puck sort
of epoxy thing with terminals on either side.

Charge one to 30 KV.

Now charge another one to 30 KV and slip it under the first one.

Ack! That's more like a Marx generator.

Yes, a mechanically commutated Marx.

Look carefully at the pelletron diagram: the pellets aren't charged from
HV supplies, they're induced ( by HV electrodes that never touch, nor
draw current); the current all comes through the drive drum, and ammeter "A".

https://jrm.phys.ksu.edu/Resource/Pics/Pelletron/28-ELEC_SCHEMATIC.jpg

Unlike a Marx generator, the voltage achieved isn't limited by the number of
elements in a stack.

Right. My capacitor chain would be low voltage, high current. The top
voltage is just the lower power supply voltage times the number of
caps that ride up one side. The mechanical input is small.

I never claimed that it was useful.

The top is interesting, there's a symmetric charge induced in the opposite sign
and carried down the returning chain.

Nothing is "induced" in my machine. It's all hard connections.

One could build it from a bunch of linked PC boards, or one long,
expensive kapton flex board. Sprockets could drive it and charge the
caps on the bottom.

Imagine a long plastic rod with a string of caps soldered in series
along it. Ground one end. Start at the other end, walking along with a
power supply, charging caps one at a time. By the time you get to the
grounded end, you've got a lot of voltage in the string. Don't charge
the string starting at the grounded end.


--

John Larkin Highland Technology, Inc
picosecond timing laser drivers and controllers

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com