circular electromagnet 1

[madfast]

Hello. I've been doing a bit of research into electro magnets and halbach arrays, neodymuim magnets and such, and was wondering if you all could help me understand how a proposed magnetic field would form in said configuration. the proposed electromagnet would be about 12" diameter with a 1/2" thick iron circle. if i took a continuous length of wire and wrapped the bar with electromaget wire, what type of magnetic field would this create, since there is no finite location of the end....like winding an iron rod with enameled wire, that would have two very obvious ends.

my other theory was to take a bunch of small bar electromagnets so that the same polarities faced inwards, and arranged them in a circular pattern... what type of magnetic field would this create? i'm looking to create a strong magnetic inner field of like polarity.

any ideas, thoughts, suggestions?

 

[logbook]

The first topology you are discussing seems to be a toroid. This is a standard coil type for inductors to give minimal external field. The external field would ideally be zero. In reality, the toroidal winding ends up as being equivalent, as far as the strays are concerned, as a single turn winding the same diameter as the toroidal ring. Needless to say this is not suitable for generating a specific intense magnetic field.

 

[madfast]

yes, i was thinking to myself how much that resembled an inductor as i was asking that question, so thank you for that answer.

one other idea was simply to make a round electromagnet, an iron circular core, with the windings wrapped the long way around. i have been searching all over trying to find magnetic field views but noone seems to have any. i even downloaded some software that shows magnetic fields, but you have to have a PHd to operate the damn thing! haha.

thanks fellas.

 

[logbook]

Not sure why you want to wrap the turns around the long way on a cylindrical core.

So you want a strong magnetic field. You and many others. How strong is strong? If you want a 1T field that is easy. Take any core shape, eg toroidal, and cut a slice through it. Wrap turns all around. The core “conducts” magnetic field easily. Air doesn’t. Most of the path is air so the H-field is not wasted in the iron areas. If you need 20T fields you can’t do it with a core because no core can support such a high field density. People then use huge capacitor banks and discharge them into air wound coils. The coil can’t support a continuous field (it would melt) but a transient field is ok.