Posts by Paradigmnoia

Anyways, continuing along with my journey that no one else cares about....
Experimenting and some handy calculators online have allowed me to configure a close approximation of the Lugano coil wiring.
(I'll make this as short as possible.)
Two twisted 15 Ga NiCr80 wires (closely approximating Inconel) can indeed be made to create a coil with 30 wraps around a 1 cm tube, with 55 cm of straight lead wires (that pass through the end caps, six leads combined for the 55 cm length) and arrive at the resistance most of us that have tried at this have come to: 1.23 Ohms total.

To explain further, my question to myself was: Can one easily build a heater using Inconel or other calibrated resistance wire that uses 20A, at any power level, and have it stabilize at 450C? Then, if it uses 20A to reach 450C, how hot could it get at 50A using the same wire? Will it only reach 780C? Could it reach 1100 C? Without any special considerations?

The answer is the wire should get very hot at 50A (or 46.9 A) if the 20A part is satisfied (or 19.7A, if you prefer). Probably much hotter than 780 C, without difficulty.

Can such a heater be made using the dimensions, mass, and suggestions from Rossi's patent with the power levels used in the report? Well, that is a bit more murky to be sure.

Using nichrome wire, amps tell you a lot. This wire type is very well characterized.

See: https://www.heatersplus.com/wire.html

This PDF is also very useful (1.3 Mb) : http://www.produktinfo.conrad.…T_ISACHROM_60_10METER.pdf

Yikes what? I think I explained myself further down. The idea was to see if the currents reported had a physical solution that matched a reasonable range of normal wire sizes and at least the dummy temperature. And it does.

I have been looking at several charts of estimated amps required to heat a bare nichrome wire of various diameters to certain temperatures. Ignoring watts for now, it is clear that using a range of possible wire sizes, if the wire can be heated to around 450 C in open air with around 20 A, then using 50 A should easily heat the wire over 900 C. 15 Ga wire is close to ideal for this.

When considering Watts instead, (ignoring electrical resistance) using about 480 W to reach 450 C, things are much less friendly when calculating the higher temperatures possible at higher wattages, like 920 W. It seems like the device can barely exceed 700 C and would require a very long period to reach thermal equilibrium at that temperature.

Reconciling the watts, amps, and temperatures is extremely difficult.

Many of those craters/pits look like the products of laser ablation-caused coulomb explosions.
Like this, for example:http://www.orslabs.com/images/sem o1 blast 1000x.jpg

@Thomas Clarke,
Did you do a calculation for the temperature for the files 1- 5 in the Lugano report? I would be interested in what you think it might be.

This is not a trick question. It might lead to another (albeit weak) solution that corroborates your position if my very rough back-of envelope calculations are within a reasonable range or error(s).

To start you off with a bit more information, your comment about the specific heat earlier set me off on a set of rough calculations. The specific heat of the device can be worked out (to some sloppy degree), and the power required to reach a temperature, and increase the temperature based on the dummy run data can be ball-parked. Steady state heat temperatures/powers can be used to estimate minimum heat transfer... etc. What I am looking at is the ability of the device to reach a certain temperature purely electrically, assuming (for the moment at least) that no unknown reactions occur.

I have received a reply from the Compact Fusion manufacturers.
It is as follows:

We have reviewed your application.. Compact FUSION only goes up to 160Amps.
Our FUSION units extend as high as 1200Amps.
Your application will work with our FUSION units if you are able to wire your load in “inside-delta” or “wye” connection.

Here is our math:
Our power controllers are rated for continuous duty. The current ratings do not increase for a lower duty cycle.
Assuming 0.4 ohm load elements:

(380/0.4)*1.732=1645 amps during on period for a delta load.
We do not have a power controller big enough for this.

(380/0.4)=950amps during on period for an inside delta load.
Use a 1000A FUSION controller.
PN: FUSION-ZC-3-DDD0-0-0001-0000

(380/1.732)/0.4=548 amps during on period for wye load.
Use a 650A FUSION controller.
PN: FUSION-ZC-3-BBB0-0-0000-0000

Additional options:
SMAFUSION-RD15 (15’ remote display kit)

.....
www.ccipower.com

@Antoine10FF,
We discussed that hot banding effect on another thread, with photos. ( The one that lead to this one) There seems to be at least two other causes that have been experimentally demonstrated for the higher heat bands.
What bothers me most about it being ascribed to directly to heater coils is the incredibly short wire length required. The non-coiled part of the heater wire is then nearly 50% of the total wire length, which is remarkably inefficient. Additionally, where are the other two coils? If that is all three, the shadow phenomena makes no sense, and still makes no sense even if that is one coil.
Electrically, the three coils in the patent application diagram are difficult enough to make work. Shortening the coil further becomes very hard to make work at all. The device was hot for a month, so massive current electrical ideas must at least be stable enough to do that. The device is almost a short circuit with conservative designs.

@Antoine10FF,
No rush required. Thanks for considering it.
For clarity, Inner core tube, ID 7 mm (D1), OD 10 mm (D2);
Outer tube (minus fins) OD 20 mm (D4), ID 16 mm (D3) [maybe 15 mm?]
Lets call the wire diameter 1.5 mm for simplicity, it should be close enough for now. Lets say that the coil is tightly wound around D2 for now.
[These D1 etc, are not all as pictured in the earlier document.]

The problem of the inside of the inner cylinder is a bit murky. We could assume a reflective inner surface coating or an opaque inner tube. I'm not sure about that. It might be worth looking at both. I will guess that it is not transparent (with fuel in it), and it might cancel itself out if it is modeled that way anyways (IE: the dummy version).

Good question.

However, the big particle does not seem to be solid nickel, simply pure nickel (at least where they tested it). It looks sponge-like.
I would suspect if the temperature was close to 1450°C, there would not have been a bunch of particles so much as a solid stick. With all sorts of added extras, perhaps that might not be the case.

Note that the nickel fuel particle tested is nearly as big, and there are several others nearly as big in at least one dimension. It wouldn't take more than a couple of those together to sinter into a rather large particle. The transformation into Ni62 is another story. (I am familiar with your opinions in that regard).

Did you see that Rossi has recently confirmed the ash was re-tested, and the Ni62 was confirmed (no word on the % unfortunately).
http://www.journal-of-nuclear-physics.com/?p=892&cpage=55#comment-1150286

We seem to have wandered off the path again..

@Antoine10FF, you say that your model assumed an Inconel core tube. How does a "dummy" core (alumina ceramic) look? I believe that the core tube in indeed alumina, although the contents ("fuel") may alter significantly the attributes compared to a hollow alumina tube.

In my estimation, the coil windings are wrapped slightly tight around an alumina core tube (They probably loosen a bit at operating temperature, possibly considerably if the coil wire ends are captive). This should improve heat transfer to the core by some degree of conduction. I am also of the opinion that an air gap exists between the inside of the outer tube and the outside of the coil windings, roughly 1 mm, (possibly as low as 0.5 mm) which mean heat must primarily radiate to the outer housing, and this air gap and radiative zone is therefore insulating to some substantial degree. The end caps seem to have the wires encapsulated at least for that 4 cm long section, or at least the wires fit fairly snuggly in grooves in the caps to admit the wires between the caps and the core tube (IMO). Something like 30% of the total heat generated by the coil wires is produced in the straight sections of the coil wires (both ends combined), based on some modelling. In this case the heat transfer to the caps is primarily conductive, at least until that is no longer a physical possibility.

I hope this helps your model, and if you have the time and are willing, I would be interested to how the above version of construction would affect your model.

Axil, Re: melting nickel, you might like: http://link.springer.com/article/10.1007%2FBF00774272

I haven't gone to the University to look up a non-pay version yet.

@Shane D.
I agree that a better signal is desirable. How one achieves that is a matter for the experimenters to solve. If a small signal is repeatable, conceivably the parameters can be adjusted to see if it can boosted by making small changes and seeing what happens, without adding more complexity. Maybe roughly 1.2 is the limit of this system. Maybe it is all just noise. Then a more sensitive and well-characterized calorimeter system could be employed so that noise is reduced. More wires is certainly another way to possibly improve the signal relative to noise. There are many variations feasible. But no one will care at if the experiment is not repeatable enough. Let's see if that can be fixed up before worrying about doing more.
The peanut gallery is full of ideas for others to try, but most just talk and don't do anything themselves. In that case, they just have to deal with what the doers are doing. Yelling at the TV screen won't affect the outcome of the show.

Nonsense or not, a functional 4 wheel wagon needs the invention of independent bearings at some point. Try and turn a twin solid axle wagon around. And if the wheels are not equal in diameter even a two wheel cart will try and turn itself around or drag one wheel... Whether or not more is obviously better, more adds complications and new problems that might not be obvious at first glance.

The point of the MFMP is to come up with a replicable experiment that can be done anywhere, by anyone with a reasonable level of skill. (Perhaps even an experiment that you would be willing to try). Adding complexity might not be effective in that regard.

First, one has to make a wheel that rolls, then one can move on to putting two together to make a cart, then four to make wagon... Ten wheels to start with might be unwieldy and not perform as expected...

I have also to add that I looked into Thomas' comments above in more detail. I found a chart of "withstand" ratings for copper wire. Actual testing has shown that a nick-free copper wire of 14 Ga will handle up to 795 A for 30 cycles (1/2 second) before melting ( 1080 C). How this translates to a higher resistance wire with a higher melting point would need some working out. The duty cycle would need to be very low if this were to be continued over an extended period of time, and the time to cool the wire between On periods would need to be considered. Actually doing this with off-the-shelf equipment is another story... I asked this of the Compact Fusion manufacturer, to see if this could be reasonably attempted in zero cross mode, or if it would trip an over current safety setting. I will report back on their answer, if they respond. They might think that I'm some sort of nut case and ignore me...

This is indeed a complex subject, and these sometimes rough arguments are excellent for paring down possibilities.
These discussions did lead me to an idea, which may or may not work, but I'll give it a shot and see if it makes sense. The information available might just be too sloppy and calculated values might be too ... wrong.

Using the resistance figures calculated for each of the power examples given in the report, the coefficient of change of resistance over the temperature range might give a clue to the actual coil wire type, or the true temperature range. Maybe both, if done carefully.

MY, I get your point better now.
I would guess that once the one wire system is figured out to a reasonable level of reliability, then scaling up to more wires and improving the apparatus is the obvious step. I personally would move up to 2, then 4, then maybe 10 if each prior version proved to be scaling up well.

Whether scaling this experiment fits the mandate of the MFMP, and is cost effective, is of course another problem. With unlimited funds I am sure they could test the possibilities and improve the calorimetry to the point of satisfying even your high standards with ease. Getting that high level of funding probably depends on lesser successes with the budget presently available.

If one wire has a COP of 1.2, won't ten wires in parallel still only have a COP of 1.2?