[mchargue]

Here’s an article that talks about 3D-printing metal pieces that change materials over the extent of the print,

http://www.kurzweilai.net/3d-printing-objects-containing-multiple-metals-and-alloys

Good to know that the technology is in place to test this.

Pat

[mchargue]

nyemi wrote:

I haven’t noticed this posted before, but it’s an idea for a business that would produce a switch that operates along the same lines. It would need work, though, to increase the current.

http://www.divtecs.com/research/high-current-high-voltage-igbt-switch/

Hi
No IGBT. (Efficiency is small, hot 🙂
I work, plasma ignition.(http://youtu.be/lKwhPeQ0lSg)
I’m using thyristors.

Any chance you could post more information about the circuit you demoed?

[mchargue]

Francisl wrote: This may be premature because we don’t have the operating characteristics for a power producing DPF, but I have a suggestion for reducing the cost of the beryllium electrodes. It is similar to previous discussions about advanced manufacturing methods for the tungsten electrodes. Selective laser melting (SLM) can create the 98-100% beryllium center electrode that is exposed to the intense x-rays. Then there is an alloy transition zone that changes from beryllium to beryllium/copper alloy and then to 100% copper base that is outside of the vacuum chamber. This would be one continuous metal piece without any welds or ohmic connections that plagued earlier electrodes.
I don’t know the planned dimensions for the beryllium center electrode but this method could reduce the amount of beryllium required.

Sounds like a great question, and a good way to combat expense if it works.

As I understand it, so long as there’s no copper interfering with x-rays, it could be used. An interesting research project would be an SLM produced piece that faded from copper to beryllium as a test for how current is conducted, and how heat is conducted.

[mchargue]

JimmyT wrote: One easy way to get 60 Hz is to drop the pulse rate to 180 Hz (if possible, we really don’t know yet do we?) and use one pulse for each of the three phases of conventional 60Hz current. As far as alternative energy goes, it will be abandoned rather quickly except for specialized applications like mountain top cell towers or freeway signs with no access to power lines.

Where are you electrical engineers?

So far as I understand it, the power that comes from the reactor will be pulsed DC. That can then be accumulated, and converted into AC for the grid.

Think of it as a hand-cranked pump filling up a bucket. Power splashes out into the bucket each time you crank the handle. From the bucket, you pull power out into a converter for the rest of the grid. So, the level in the bucket rises & falls, but keeps some average level required by the converter. So long as the reactor can supply enough power to keep that average, all is good.

[mchargue]

vansig wrote: didnt Google commit some funding awhile back?

Ther was a GoolgeX video/presentation. However, I don’t know that Google ever funded LPP.

[mchargue]

I think it’s interesting, too. As the gradient of the electric field rises, it’ll be interesting to see what, if anything, pops out.

[mchargue]

Di Vita: Thank you very much for sharing your expertise here. I appreciate the insight, and the chance to expand my understanding of the subject.

[mchargue]

I welcome the company, and I hope others write google, too. Post here if you wrote google.

[mchargue]

C’mon folks. Did no one else repeat this suggestion to Google? Heck, write a letter!

[mchargue]

Zap;

The short URL you posted isn’t working for me. Here’s the full URL for others that may need it,

https://www.indiegogo.com/projects/focus-fusion-empowertheworld–3

I already contributed, and am talking this up to others.

Edit:

Seems having the correct URL doesn’t matter. You need to copy/paste the text of the URL into your browser. Something about the way this board formats the link goofs it up.

[mchargue]

More faith-based physics in the making…

[mchargue]

Henning wrote: Please be aware, that the discharge time is crucial. The switch has to operate 45 kV / 2.8 MA within 100 µs or better (something of this order). And the capacitors / electric sources have to supply them within that time.

I don’t have the graphs currently, but this is a steep increase in power over time.

True that. but if you look at what many compulsator’s are used for – railguns – the need is the same. Right now, a railgun’s payload spends very little time in the barrel. Projections for future needs – higher velocities & shorter barrels – means that the time is only going to decrease. From what I can determine, the technology’s not quite there yet – but mine was not an exhaustive search.

Mostly, I’m considering the advantages that would come from having to switch a much smaller current (on the order of 10kA) through the rotor field winding to control a much larger output current from the stator. The ‘compensated alternator’ (compulsator) is designed in such a way to produce large current/voltage spikes, and may be applicable to FoFu’s needs.

From what I can find, it’s not a hot topic of research outside of DARPA, but there are some PDFs that describe this well. In addition to this, I have seen other descriptions of experiments that have devices that come much closer (factor of 40) to what FoFu needs.

Some FYI:
http://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=1108&context=aerosp

Pat

[mchargue]

mchargue wrote:

You are correct that the largest piece is the capacitors. Super capacitor technology is advancing quickly but they are the wrong kind of capacitors. The capacitors for FoFu require low inductance, fast discharge current and high voltage. Super capacitors tend to be low voltage, slow discharge capacitors. It is challenging to reduce the size of high voltage capacitors that can discharge as needed in FoFu. Other technologies may replace capacitors but a FoFu reactor will still need shielding. I can imagine a 5 MW reactor with everything fitting in a 1 car garage but much small than that is unlikely.

What other technology might replace capacitors in this application?

TIA;
Pat

Well, here’s something interesting in pulse-power systems: a ‘Compensated pulsed alternator’, or compulsator
https://en.wikipedia.org/wiki/Compensated_pulsed_alternator

This takes the energy of motion, and uses that to drive a high-current systems, like railguns. Not sure what the output voltage is, though I expect that can be tuned. Given that something like this can be used, would this eliminate the high-current, high-voltage switch? (spark-gap now) If you’re switching on a (relatively) low-power excitation field used to stop the flywheel – which will then give up it’s energy as a high-current, high-voltage spike – can your use that to shape the FoFu power pulse?

Maybe this in combination with something that can compress the compulsator’s output pulse into something more usable by FoFu…?

Maybe this?
http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=6191525&url=http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6191525

Or some of these?
http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=6188417

You folks need to fins a grad student trying to make his bones in the pulsed-power field, and convince him there’s a thesis topic in this.

Patrick

[mchargue]

asymmetric_implosion wrote: You are correct that the largest piece is the capacitors. Super capacitor technology is advancing quickly but they are the wrong kind of capacitors. The capacitors for FoFu require low inductance, fast discharge current and high voltage. Super capacitors tend to be low voltage, slow discharge capacitors. It is challenging to reduce the size of high voltage capacitors that can discharge as needed in FoFu. Other technologies may replace capacitors but a FoFu reactor will still need shielding. I can imagine a 5 MW reactor with everything fitting in a 1 car garage but much small than that is unlikely.

What other technology might replace capacitors in this application?

TIA;
Pat

[mchargue]

I haven’t noticed this posted before, but it’s an idea for a business that would produce a switch that operates along the same lines. It would need work, though, to increase the current.

http://www.divtecs.com/research/high-current-high-voltage-igbt-switch/

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