Width of a coil to Width of magnet

[GreenTeam]

How much wider can I coil be to the width of a magnet?
For some reason, i suspect that a coil can be quite wide as long as there is
sufficent flux to saturate entire coil? Or is it somehow related to some designs where
the end turn is out of play but part of the design?
I am thinking maybe 2x the width of the coil?

errrr....that was confusing lol

okies, I am thinking that the coil may be as much as 2x as wide as the magnet used?
I come to this conclusion because I made a DIY magnet line viewer by cutting up steel wooll and
putting it into baby oil in a clear plastic bottle. Than I shake the bottle and lay over top of a magnet and
the magnetism grabs the steel wool bits in patterns. This way, I can see how far out the field lines travel.
I also am hoping that with this I can discover if i am having intermagnet flux loss from magnets being to close to each other.

But, basically, it appears to me that the field lines are as much as 100 percent the width of the magnet.
I can post pics if it helps.

[SparWeb]

In the case of the axial flux alternator, the word "width" of either magnet or coil really means "arc that it spans" but I think we all get what it means.

The coil should be wider than the magnet.  Being the same width is also OK.  Making the coil narrower than the magnet is just a waste.  Not all of the flux can pass through the coil if it's smaller than the magnet.  The coil can be wider but making it too wide is also a waste.

Another way to put it...  say you have an old fashioned over-shot waterwheel and you build a sluice to pour water over it.  The buckets of the wheel are 1 foot across.  Would you build a gate in the sluice 2 feet wide, spilling the water on either side of the bucket?  No, you would make the gate a bit narrower than the bucket to get all the water to flow into each bucket.

[MattM]

How does that theory about width work if you use a flat spiral coil?

[Mary B]

Flat wire has been tried... eddy currents get bad and lots of heating

[MattM]

Flat wire coil and flat spiral aren't the same.

[Mary B]

Someone did a flat spiral using  really thin circuit board etched and stacked... yup, eddy currents... I forget how long ago this was discussed... back when the Dan's owned the board...

[MattM]

I'm going to be using 14 AWG.  I need to get a proper magnet and a better voltage meter yet.