Self accelerating reed switch magnet spinner.

[conradelektro]

In this post http://www.overunity.com/13852/self-accelerating-reed-switch-magnet-spinner/msg378265/#msg378265 you see my "big model" (250 mm long beass axis, 5 mm diameter) with the base magnets flatly underneath the ends of the axis. It needed two ring magnets on both ends of the axis to work properly. There is interference of the central (diametrically magnetised) ring magnet on the axis with the base magnets. But this interference does not stop the spinning of the axis quickly. It still spins about a minute when started by hand.

Now I changed the "big model" by placing the base magnets in an upright position (like most people do with ring magnets in their builds). The base magnets act much better in this position (upright), only one ring magnet on both ends of the axis is needed to make it work. But now the interaction of the central ring magnet with the base magnets is severe. This unwanted interference stops any spinning of the axis rather quickly (within a few seconds).

I see no obvious way of counteracting this unwanted inteference. Any ideas out there. (I could of course go back to the flat position of the base magnets, but also there is some interference.)

Greetings, Conrad

[MeggerMan]

@Conrad,
You could try some mu-metal sheet to shield the centre magnet from the support magnets.
Two sheets either side with a hole in them for the shaft to go through should provide the shielding you need.


Meggerman.

[conradelektro]

@Conrad,
You could try some mu-metal sheet to shield the centre magnet from the support magnets.
Two sheets either side with a hole in them for the shaft to go through should provide the shielding you need.


Meggerman.

I guess Mu-Metal will also slow down the central magnet. Does Mu-Metal interact with a magnet? I tried to put a common steel plate near the central ring magnet and its effect is terrible (on any magnet).

Mu-Metal is also used as a core material for coils, so it must be magnetic (must interact with magnets like iron or steel, only more so). But I am no expert.

I just found this: http://www.abschirmungen.eu/deutsch/produkte/faq/

"Es gibt kein Material, das die magnetischen Felder stoppt ohne selber von der magnetischen Kraft angezogen zu werden."

Translation: "There is no material which can stop magnetic fields without being itself atracted by the magnetic force."

That seems to highlight the problem with Mu-Metal near a turning magnet.

Greetings, Conrad

[synchro1]

@Conradelectro,


                        Jonny Davro extended his axel to perhaps twice the length of yours to eliminate that magnetic drag.

[conradelektro]

@Conradelectro,


                        Jonny Davro extended his axel to perhaps twice the length of yours to eliminate that magnetic drag.

That is a good idea, I might do that as well. Does Jonny Davro show a video with that contraption?

Or I use a vertical axis stabilised on top by a magnet and having a "needle bearing" on the bottom like my little motor in this video https://www.youtube.com/watch?v=OqQSJjRJ6EQ

Greetings, Conrad