stacked stators and rotors PMA

[GoVertical]

Greetings, I started working a 6 inch diameter PMA. I completed inner rotors for 6 inch diameter PMA. The rotors require no glue for assembly. 5/8 hole was drilled first for the inner smaller magnets which are 2 5/8 x 1/8 disks. Then a ¾ inch was drilled to hold the larger ¾ x 1 inch outer magnets. The pull force of the magnet hold themselves in place without the need for glue. Assembly was very fast and easy.

Grüße, Istarted Arbeiten auf einem 6 Zoll Durchmesser PMA. Ich absolvierte inneren Rotor für 6 Zoll Durchmesser PMA. Die Rotoren erfordern kein Klebstoff für die Montage. 5 / 8 Loch gebohrt wurde zunächst für die innere kleinere Magnete, die 2 8.5 x 1 / 8 Scheiben sind. Dann wird eine ¾ Zoll wurde gebohrt, um den größeren ¾ x 1 Zoll äußeren Magnete halten. Die Zugkraft des Magneten halten sich in Ort ohne Klebstoff. Versammlung war sehr schnell und einfach.

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[Bernd]

If i understand you well then you use the inner smaller magnets just to fix the outer bigger magnets without glue.
The forces which fix the magnets are caused by a flux between the inner and outer magnets.
This flux is no longer available for passing through the copper coils. With other words, you take a part of the
possible maximum flux away to fix the magnets on position.

Grüsse

Bernd

[GoVertical]

Greetings, I am not sure if it is losing any strength, by stacking the magnets I think the strength accumulates. I have been trying to find a research paper on the subject but I have not found it yet. I may be wrong. I plan on asking some people at a local university in few days to find out what really is happening. Thank you for the input.

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Grüße, ich bin nicht sicher, ob es zu verlieren ist keine Stärke, durch Stapeln der Magnete Ich glaube, die Stärke anfällt. Ich habe versucht, eine wissenschaftliche Arbeit zu diesem Thema zu finden, aber ich habe sie noch nicht gefunden. Ich kann mich irren. Ich plane fragen manche Menschen an einer örtlichen Universität in wenigen Tagen um herauszufinden, was wirklich geschieht. Vielen Dank für die Eingabe.

[Bernd]

I wasn't talking about stacking, i meant the second magnetic path through the new little magnets beside
the big ones. The flux their is taken away from the flux through the coils.
It seem to be better you simulate your setup into FEMM .

The stacking is decreasing the flux because the flux path gets longer and longer as more plates you are stacking.
If i remember well then Steve has simulated such a setup some month ago.
For the flux height the length of the full flux path through the air is important.

Grüsse

Bernd

[GoVertical]

Greetings, I made a very simple experiment. I placed a single magnet on each side of a 0.5 inch of plastic board. Then I tried to pull off one of the magnets. I repeated the process using stacked magnets. The stacked magnets are much more difficult to pull off. This suggests that the pull force accumulates. I am still searching for a research paper on the subject.

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Grüße, ich habe ein sehr einfaches Experiment. Ich legte einen einzigen Magneten auf jeder Seite einen 0,5 Zoll aus Kunststoff Bord. Dann versuchte ich abziehen einer der Magnete. Ich wiederholte den Prozess mit gestapelten Magnete. Die gestapelten Magnete sind viel schwieriger zu abziehen. Dies deutet darauf hin, dass die Zugkraft ansammelt. Ich bin noch auf der Suche nach einer Forschungsarbeit über das Thema.

[Bernd]

But this experiement shows not the same like into a stacked alternator.
In the alternator you got airgaps between the magnet plates where the flux has to path through.
Remember that the flux has to path one magnet after the other to get to the other side of the alternator.
Then the flux goes through the iron ring and again it has to path all the stacked magnets and airgaps to went back
to the othe side of the magnet where it was coming from.

I don't want to say that it is not working. I just want to say that a normal iron dual plate alternator delivers much
more flux into its airgap. The advantage that i see is the fact that you alternator doesn't need so much iron and can
be made out of plywood or something like that.

I am pretty shure that Steve had simulated exactly your setup.

EDIT:
I found the older thread where Steve showed some FEMM simulations for stacking of magnet plates.
The flux decrease the more plates we use, but not as much as i thought.
On this side you can see the pictures. You have to scroll down.

http://www.vawts.net/forum.spark?aBID=1 ... ewestFirst

Grüsse

Bernd

[GoVertical]

Greetings, I found this picture that shows what happens to magnets when you put them together. It becomes one big magnets. It does not show any second flux path.

Grüße, Ich habe dieses Bild, dass was passiert, Magnete, wenn Sie sie zusammen zeigt. Es wird eine große Magneten. Es zeigt nicht jede Sekunde Flusspfad.

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[Bernd]

I think i have misunderstood the sense of the (new) additional little magnets you spoke about.
Can you explain where they are placed and what they are used for ?
I can't see them into the pictures.

Before i thought they were places beside the big ones to hold the big ones with side forece on places.
But now i think they are placed between two big magnets, into the wooden plate to hold the
two big magnets in there holes into the wooden plate ?

Grüsse

Bernd

[GoVertical]

Greetings, Thank you for finding the thread. I missed that one. I down loaded the FEMM program it will take me sometime to learn how to use it. The space between the vertical columns is about twice the air gap distance. Will FEMM allow me create that simulation?
Thanks again.

Grüße, ich danke Ihnen für die Suche nach den Faden. Ich vermisste, dass man. Ich herunter geladen FEMM Programm es mich treffen wird irgendwann zu lernen, wie man es benutzt. Der Raum zwischen den vertikalen Säulen ist etwa doppelt so Luftspalt zu erreichen. Will FEMM erlauben Sie mir zu schaffen, dass die Simulation?
Nochmals vielen Dank.

[GoVertical]

Before i thought they were places beside the big ones to hold the big ones with side forece on places.
But now i think they are placed between two big magnets, into the wooden plate to hold the
two big magnets in there holes into the wooden plate ?



Bernd

Greetings, yes this is how I am using them.

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