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

 

[astrokreng]

I would say that your visual image is a good representation of what the field lines of a ring of magnets would look like if all the magnets were facing the same direction. The magnetic field would indeed emanate from the outside of the ring and curl back up and down, returning to the center from all angles. However, the strength and direction of the magnetic field at any given point would depend on the strength and direction of each individual magnet within the ring. If all the magnets are facing the same direction, the resulting magnetic field may be stronger in that direction, but it may also be less uniform and may have more complex patterns of field lines. Whether this would be useful for your specific application would depend on the specific design and purpose of your permanent magnet alternator. It is possible that this arrangement could provide a useful magnetic field, but it would require further analysis and testing to determine its effectiveness. Overall, your approach is interesting and may have potential, but it would require further experimentation and analysis to fully understand its capabilities.