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http://www.dailykos.com/storyonly/2008/4/24/19392/2417
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Another KOS Diary On IEC/Bussard
Another KOS Diary On IEC/Bussard
Engineering is the art of making what you want from what you can get at a profit.
great to see
it`s great to see such enthusiasm. I wonder how far the news about polywell has got.
Won`t be too long now...
Won`t be too long now...
What amazes me about this is that who ever wrote the diary has never been at any of the places we all hang out (as far as I can tell) and yet the person is totally up to speed. He does mention Roger Fox's previous diary.
I'm seeing that more and more.
Which means we are now building a base that doesn't even depend on us.
Last summer when we were so desperate to get WB-7 funded it was our fondest wish and yet beyond what we even dreamed of.
I'm seeing that more and more.
Which means we are now building a base that doesn't even depend on us.
Last summer when we were so desperate to get WB-7 funded it was our fondest wish and yet beyond what we even dreamed of.
Engineering is the art of making what you want from what you can get at a profit.
hmmm... I'm seeing some errors in this post... about halfway down the page it says:
One more quibble:
I thought the electrons dominated the mix by one part in 10^6.Further, they found they could get D-D fusion (deuterium - deuterium), with the electron potential provided by maintaining a million more electrons per cubic centimeter than deuterium ions. If there were say 5 million deuterium ions per cc, 6 million electrons per cc would be enough.
This I'm less sure of. I didn't think that the last WB6 was a go-for-broke kind of test, but simply where they wanted to do a test; the coils had shorted from all the previous testing, and could barely do one more.A fifth and final test deliberately pushed WB6 to its limits, blew out a coil, but gave them one last batch of data.
One more quibble:
These were net-power machines - demo power plants, not break-even machines.Dr. Bussard estimated a 1.5 meter Polywell reactor could be built for $150 million that would be able to hit break even burning just deuterium; $200 million would get a reactor able to burn p-B11 fuel successfully while reaching break even.
John P
I don't know if you are interested in this, but we think we know what happened to the WB-6 and why. When you fire the coils on a polywell, they heat. The coils are located inside the vacuum chamber. It keeps the heat from escaping the coils just like a thermos bottle insulates your coffee. If the current is on too long or the machine is fired too often, then the insulation on the wires can melt and short to the case. In the WB-6 it worked like an arc welder and burned a hole in the case. The inside of the coils were at air pressure, so the pressure in the chamber went through the roof. Then the HV turned on. And things got exciting.
I don't know if you are interested in this, but we think we know what happened to the WB-6 and why. When you fire the coils on a polywell, they heat. The coils are located inside the vacuum chamber. It keeps the heat from escaping the coils just like a thermos bottle insulates your coffee. If the current is on too long or the machine is fired too often, then the insulation on the wires can melt and short to the case. In the WB-6 it worked like an arc welder and burned a hole in the case. The inside of the coils were at air pressure, so the pressure in the chamber went through the roof. Then the HV turned on. And things got exciting.
Yes, I am interested! I think, in Dr. B's google video, he talked about the wire varnish being worn away by repeated testing, and getting shorted out. Now, if it merely shorted out a bit of the coil to itself, not such a big deal, you'd lose a little of the field. But shorting to the case, that's bad.rnebel wrote:John P
I don't know if you are interested in this, but we think we know what happened to the WB-6 and why. ... And things got exciting.
Are you at liberty to discuss how you remedy this in WB-7? Better grade magnet wire? Insulation on the inside of the case? Active cooling has been discussed in some detail on this board (Simon has written about concentric tubes carrying water and LN2 IIRC) but I'm guessing that would have to wait for later prototypes.
John P
This may sound a little strange, but we figured this out from the WB-7 by looking at the residual gas analyzer (rga). After we did several test shots on the W-7 coils we noticed that the water content in the vacuum chamber went up and stayed up. Stainless steel outgasses water when you heat it. The water pressure in the vacuum was from the coil casing. It took hours for the temperature and the water content to come down. The only way the coils can cool is through the leads, which is real slow. The cure is real simple: make the coil pulses as short as you can and monitor the temperature in the coils by measuring their resistance. Works like a charm.
This may sound a little strange, but we figured this out from the WB-7 by looking at the residual gas analyzer (rga). After we did several test shots on the W-7 coils we noticed that the water content in the vacuum chamber went up and stayed up. Stainless steel outgasses water when you heat it. The water pressure in the vacuum was from the coil casing. It took hours for the temperature and the water content to come down. The only way the coils can cool is through the leads, which is real slow. The cure is real simple: make the coil pulses as short as you can and monitor the temperature in the coils by measuring their resistance. Works like a charm.
What would happen if the coils had a thin layer of boron carbide or boron nitride as its insulating layer?
Would the magnetic field lines expand just like they would with a standard plastic insulation?
I was thinking of a way to cool the wire down and boron nitride and carbide have good thermal conduction properties.
The coatings would be applied by a PVD device.(I imagine)
Would the magnetic field lines expand just like they would with a standard plastic insulation?
I was thinking of a way to cool the wire down and boron nitride and carbide have good thermal conduction properties.
The coatings would be applied by a PVD device.(I imagine)
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pstoller78
- Posts: 14
- Joined: Fri Jun 29, 2007 2:45 am
Yep.pstoller78 wrote:Does this rule out WB-7 working in continuous operating mode?The only way the coils can cool is through the leads, which is real slow. The cure is real simple: make the coil pulses as short as you can and monitor the temperature in the coils by measuring their resistance. Works like a charm.
Tom.Cuddihy
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Faith is the foundation of reason.
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Faith is the foundation of reason.
^Yes But i believe there still exists the possibility of a Quasi-Continuous Polywell
I could remember Dr Bussard mentioned how the LCR parameters of WB6's coils weren't damped adequately. Have you changed anything for WB7 ?
Until materials science catches up and provides us with our dreams of super conducting coils would it be out of the question to consider an AC Polywell ?
Imagine connecting the polywells coils to a powerful LC Tank circuit. Such systems already exist for 50 hz Industrial power conditioning. If one could establish a perfectly resonant circuit then one would need only minimal power hardware such as IGBT to "ring up" the coils to high power factors, similar to Tesla Coil operation but at a lower frequency. The LCR circuit would be perfectly damped minimizing stress on precious hardware. AC operation could also help reduce the critical thermal problems we will continue to face.
Rather than trying to synchronize everything to a "big bang" a sine wave would produce a novel timebase to sync the experiment to.
The magnetic field of a 50hz system will be at its maximum at a rate twice that. So the question is how much science can we do in 1/100th of a second, again and again and again until it gets too hot.
Hence a Quasi Continuous Polywell.
Dr Nebel could the inductance of the coils fight against short pulsed experiments ? Synchronizing everything would be tricky also.rnebel wrote: The cure is real simple: make the coil pulses as short as you can and monitor the temperature in the coils by measuring their resistance. Works like a charm.
I could remember Dr Bussard mentioned how the LCR parameters of WB6's coils weren't damped adequately. Have you changed anything for WB7 ?
Until materials science catches up and provides us with our dreams of super conducting coils would it be out of the question to consider an AC Polywell ?
Imagine connecting the polywells coils to a powerful LC Tank circuit. Such systems already exist for 50 hz Industrial power conditioning. If one could establish a perfectly resonant circuit then one would need only minimal power hardware such as IGBT to "ring up" the coils to high power factors, similar to Tesla Coil operation but at a lower frequency. The LCR circuit would be perfectly damped minimizing stress on precious hardware. AC operation could also help reduce the critical thermal problems we will continue to face.
Rather than trying to synchronize everything to a "big bang" a sine wave would produce a novel timebase to sync the experiment to.
The magnetic field of a 50hz system will be at its maximum at a rate twice that. So the question is how much science can we do in 1/100th of a second, again and again and again until it gets too hot.
Hence a Quasi Continuous Polywell.
Purity is Power
Perfect damping = high losses.
Pure AC on the coils would turn the machine "inside out" once every cycle. i.e all the particle flows at right angles to the coils would reverse. You also lose magnetic confinement.
For pulsed operation the key parameter is L/R (inductive time constant). It can be adjusted by adding external resistance at the price of increasing power losses and using higher voltage drive.
Pure AC on the coils would turn the machine "inside out" once every cycle. i.e all the particle flows at right angles to the coils would reverse. You also lose magnetic confinement.
For pulsed operation the key parameter is L/R (inductive time constant). It can be adjusted by adding external resistance at the price of increasing power losses and using higher voltage drive.
Engineering is the art of making what you want from what you can get at a profit.
Yep. 100% But look at the timeframe involved for WB6's tests.MSimon wrote: Pure AC on the coils would turn the machine "inside out" once every cycle. i.e all the particle flows at right angles to the coils would reverse. You also lose magnetic confinement.
WB6's magnetic field barely lasted 1/1000th of a second. A 50hz AC polywell would have a maximum field for 1/100th of a second. A 10x improvement with simplified hardware.
I think there is a hell of alot of science you could do in 1/100th of a second.
Superconductors are so attractive because of their energy storage. LC circuits also store energy, only with resistive losses. Still because this resonant system would largely be outside the reactor, minimizing ohmic losses with simple cryogenics systems would be possible.
At the moment the experiments are just one shot. This is a novel way of getting a lot more bang for your buck. It is not a means of constant confinement but you could get a multitude of data sets instead of one. Results would be rock solid. If you ran it of D-D, how is anyone going to question the validity of your neutron counts if it was producing consistent counts in sync with the resonant frequency of the machine.
Also Remember there are two ways to achieve B=1. Increasing electron pressure and increasing magnetic pressure. An AC polywell will provide a novel way of studying the later.
Purity is Power
If the coils are at atmosphere, just pump air through. It'll give you some cooling. Water would be much better, but then you have to deal with the plumbing. Both air and water are way cheaper and easier than liquid nitrogen, and for a quick test set up that's important.
Just moving air in the coil frame will help speed up the number of runs in a day, and I bet that can be done with little money and short time. If it takes a week to get twice as many runs per day for the rest of the summer, I'd think that would be something to look at.
Boy, can you tell I wish I was playing with those toys!!
Just moving air in the coil frame will help speed up the number of runs in a day, and I bet that can be done with little money and short time. If it takes a week to get twice as many runs per day for the rest of the summer, I'd think that would be something to look at.
Boy, can you tell I wish I was playing with those toys!!