Aluminum and magnets

[sykavy]

I was at the science museum the other day and they had an exibit on electricity. One was very interesting, they had a ring of aluminum on top of an insulator(plastic) under which was an electromagnet. They charged pretty big capacitor, i think, then released it to the electro-magnetic coil and that disk of aluminum shot into the air about 30 feet. Does anyone out there understand what im talking about? Unfortunately there was no one to ask while i was there and the sign explaining it didnt expalin much.

It may not be practical as a motor effect because of the energy necessary to cause this effect but it was very curious to me. I thought Aluminum was non magnetic.

[gyula]

induced current

Hi,

I think the changing flux of the cap discharge into the electromagnet induced currents in the alu ring and this current's magnetic field was in repel with the electromagnet field (alu ring is a one turn coil shorted in itself).

You mentioned alu disk for second, if it was a disk shape that jumped up the changing flux from the electromagnet must have induced eddy currents in the alu disk and the created field by the eddy currents were in repel to the electromagnet's field.
Of course alu is nonmagnetic, in fact it is of diamagnetic property. If you induce or make current flow in it, it can behave as a magnet. Just the shape is unusual.

regards
Gyula

[Peter Lindemann]

The Secret...

Sykavy,

Gyula is essentially correct, except the main winding AND the "shorted turn" are both in the machine that throws the aluminum plate. Go to the following link on Rex Research. This machine, called the "Master Magnet" will attract ALL materials that conduct electricity IF they are smaller than the diameter of the copper washers. But it will repel any large plate of metal, like aluminum, that is larger than the copper washers. If you punch this coil with a capacitor discharge, it will throw the plate, like what you saw.

These plans were developed by Pete Charles and submitted to Rex by me. I saw the first one built in 1983.

Master Magnet: Attracts non-ferrous metal objects by AC induction!

Enjoy,

Peter

[sykavy]

Sykavy,

Gyula is essentially correct, except the main winding AND the "shorted turn" are both in the machine that throws the aluminum plate. Go to the following link on Rex Research. This machine, called the "Master Magnet" will attract ALL materials that conduct electricity IF they are smaller than the diameter of the copper washers. But it will repel any large plate of metal, like aluminum, that is larger than the copper washers. If you punch this coil with a capacitor discharge, it will throw the plate, like what you saw.

These plans were developed by Pete Charles and submitted to Rex by me. I saw the first one built in 1983.

Master Magnet: Attracts non-ferrous metal objects by AC induction!

Enjoy,

Peter

Thanks,gyula and Peter, that was really cool. Magnets are very mysterious to me still, again thanks

[sykavy]

I was wondering about aluminum wire used for a magnetic coil are there any advantages?
Im trying to read books on electricity and i just found and old one called the "Handbook of Electronic Engineering" MacGraw-Hill 10th edition. It has a section solinoids with steel plungers. They mentioned using aluminum for high temperture plunger coils. They said that you could use bare aluminum wire and the heat would form an oxidized insulator. I was just curious again.

Is there anyone out there trying to do the Lindeman motor? Id be interested in any results. I am between jobs right now but as soon as i get any extra money im going to try it.