Field lines of a ring of magnets?

[dfinch]

Hi I'm trying to build a permanent magnet alternator with a different approach than usual. Most PMAs have a ring of magnets alternating north and south. But I'm wondering what would the field lines look like if ALL the magnets faced one direction? Would it provide a useful magnetic field, or does it cancel itself out somehow?

Here's my visual image of what I'd expect to see:

http://fenstalker.com/content/ring_magnet.gif

I know my arrows are confusing, but the idea is that the fields would emanate from the outside of the ring, then curl back up and down, returning to the center, from all angles. Is this accurate?

Your thoughts?

Thanks!
-brian

 

[Bob S]

Hi dfinch-
For an alternator, there are two choices for a permanent magnet rotor; Axial field (field parallel to the alternator axis) or radial field. The coil design and layout is much easier for the axial field magnet design. See
http://www.fieldlines.com/story/2009/4/4/214533/4539
Bob S