Quote from: pese on February 19, 2008, 03:14:15 AM

Quote from: aether22 on February 19, 2008, 02:31:55 AM


Anyway the final variation would be to have one core hugging coil and another larger coil of the same number of turns in reverse series on the same outer leg (not center bar preferably) of a transformer as the primary.

This would still create a magnetic field in the core but the compound primary coil would be immune to anything going on in the core since it would induce equally and oppositly in each coil.

So a normal secondary (or better yet a compound one) would not load or effect the primary in any way.

Are there differences, while winding sense? CCW / CW?
Have  Sec-1 and Sec-2 Windings same sense?
Is there a difference if wrapped differently?

That the 2 coil with the AC phase be observed, is a different matter
Pese

Winding sense is unimportant as long as the are connected together in the right way, the electrons must be going cw in one coil and ccw in the other.

If anyone is interested and has the skill to create a 3D magnetic simulation, preferable of the primary with an equal number of turns CW and CCW (at very different diameters) to verify that it would create a net magnetic field in the core that would be good. (I have verified with magnetic simulation calculators that the field strength is greater (12x greater in the example I gave with 2cm .vs 20cm) but not simulated how it would act in a full magnetic circuit.

@ather22

This is interesting, similar design to our Stubblefield coil in the earth batteries thread..  What is the difference in having this primary within the secondaries  Thats the similarity im seeing.. I think it has something to do with there being a magnetic field on the inside and outside of the primary and utilizing both.  Cant wait to hear your results with it.
                                                                                                                                      Joe

So what does everyone think?

Can you see how it wouldn't work?

Do you understand the concept?

Agree/Disagree?


Update:

Just ran calculations and found that for a long coil, diameter has little effect on field strength so it is desirible to to keep the coils somewhat short. (perhaps only the outer one? or only the inner one? not sure yet)

This also means that if you make the above transformer as shown it's preformance will be slightly less since it's not quite a hoop coil, though it doesn't seem far from it IMO.

I considered if the core effectivly made it into an infinite length coil which would stop it from working at all but feel quite confident that is not the case.

Just tried simulating a setup with 2 coils, one larger with 1/2 - 1/4 the flux density of the other smaller one.

And while I won't post pictures unless anyone requests them it is working very well, the smaller denser field is directing the field in the toroid core.

So I have now simulated a secondary which is totally immune to any flux change in the core and it produces a magnetic field just fine!

Alas it wasn't to be, I was right to scrap the idea oh so many years ago (or so it seems).
I tried the initial simulations with coil.magnets and they showed it working very very well.

So I then found the vertical wire option and made a virtual coil cross section with it only to get the results no one wanted, while the smaller coil won directly over where it was 'wound' the larger coil won the rest of the toroid.

Now while I can't ensure it would stop it from being successful it seems likely, the idea is afterall busted if the flux returns inside of the larger coil by not staying in the core.

So while I don't understand the difference in results I fear these results are most probably the more accurate ones.

Oh, and I simulated Thanes toridal transformer and it doesn't work either (flux went through the airgap), though I think he already said that simulations don't agree with his transformer


Update: Further tests show that if the outer coil is SLIGHTLY weaker, even 1/10th fewer turns then the field of the tighter coil will happily win, in fact if the other coil is tightly wound the one with slightly more flux totally defeats it (due to the core amplifying the field of the winner).
The problem with this is that under such a setup, you'd have plenty of flux in the core until the the secondary pulled a slight bit of it's own current and suddenly the other side would win or it would become a tie.


I will note though that I did find something interesting which may have FE implications.

Quote from: aether22 on February 20, 2008, 03:29:05 AM
Oh, and I simulated Thanes toridal transformer and it doesn't work either (flux went through the airgap), though I think he already said that simulations don't agree with his transformer

It works for me in simulation (vizimag), but you have to be careful to look at the real numbers instead of the pictures, because in realizable configurations, the secondaries do pump flux through the primary, but much less than they pump through the loop.

If you simulate the state with both secondaries on, you'll find that the primary becomes a hot spot, because most of the flux in the toroid is cancelled out.  The picture that vizimag draws of this looks just like all the flux from the secondaries is being directed through the primary, but it isn't so!  It just looks that way because vizimag renders relative flux density.  If you put it into absolute mode, and look at the actual flux measurements, you'll find that the flux through the primary when both secondaries are energized is much less than twice the flux through the loop when a single secondary is energized.

So, if you calculate the efficiency of the transformer when built and driven correctly, based on the vizimag flux model, it can come out overunity even though it's not perfect.