Permanent magnet motor

[Jim36]

Hi all,

The tube magnets have arrived but on initial testing the field is not correct  , I will try to redeem the experiment and possibly have them corrected here in the UK.

See pictures in following post of tube magnets.

Jim

[lumen]

I was trying to get a response from a similar setup by using about 10 diametrically polarized cylinders forming a ring.
The ring of magnets had almost no external field after forming them into the ring, so it was a magnetic ring just like the field around a wire with current.

It seems that if the field is contained internally there is no way another outside field can affect it and the experiment did nothing.

[ayeaye]

Maybe it may work when the ring magnet is thin, it takes 10 mm of iron to shield the magnetic field in any noticeable way.

But if the permanent magnet motors are not the way to go at all, then it's of course better to know it.

Jim36, you have at least the magnets, so you can magnetize them. Such tube-like magnets may though be the worst, in that not many of these thick wires needed for magnetizing circularly, can go in there. The best for the purpose is likely a ring magnet with a possibly larger hole. For that money you could buy a welder instead, and you could magnetize magnets by yourself as much as you want. A microwave transformer may also do that, some use it for welding, but also may not be powerful enough.

[Jim36]

Lumen, you maybe correct and the external field will have no effect, this is something i'm not sure of.

Ayeaye, yes I was thinking of getting the holes made wider for the reasons you have just mentioned, will see if I can get things moving forward.

Jim

[ayeaye]

Jim36, Lumen, i think the field of the external magnet should go inside the circularly magnetized magnet, and still create a force. The only thing that prevents that, i think, is magnetic shielding of the metal of the circularly magnetized magnet. But shielding a magnetic field needs at least 10 mm of iron, so when the circularly magnetized magnet is thinner (less difference between the outside and inside diameter), then there may be an effect, when it is, say 20 mm thick, then maybe not. I'm not sure about numbers, didn't calculate anything, but i have found that a 10 mm of iron can shield the magnetic field. What do you think, right, wrong?

This may also mean that the external magnet should be quite near the circularly magnetized magnet, as the circularly magnetized magnet has no field outside.