FrankG said:
I don't mean to discourage you, but having worked in a motor/generator
repair shop, you still have a problem with your magnet/coil layout.
As I understand your design, you have 24 magnetic poles, and 8 coils. And
from your description, the magnets are arranged on one disk, and the coils
on another that is to be mounted very close to the magnet disk. And there
will be a steel/iron plate behind the coils? That part I can't tell for
sure.
Looking at how the magnets are arranged, N pole of one next to the S pole of
the next, I'm not clear how the magnetic flux will pass from the pole of
one, across a coil side, into the steel backing and return across another
coil side back to the S pole of the neighboring magnet. It seems the flux
would have an easier path to just jump from one magnet's N pole to the next
magnet's S pole and only a fringe of flux would pass up wards from the disk
to where the coil is spinning.
Instead of breaking the magnets in half, you might try mounting them so the
N pole of one is next to the N pole of the next. Followed by it's S pole
next to the S pole of the third, and so on. Then the flux from both N poles
would be opposing, and would have to rise up out of the disk, to where you
have the coils spinning. This would be hard to first hold in place since
the magnets would naturally repel one another, but I think you'll get more
voltage for a given coil setup/speed.
Another thought is that ideally the number of coils should equal the number
of poles in a single phase machine. With the odd ratio of 3 poles per coil,
however you connect the coils together, there will be times when the voltage
developed in one will be opposing that of another. Mind, I understand that
winding 24 coils to fit in the same circumference would seem to be a
challenge. But it is done all the time with commercial machines by
overlapping the coils. If one side of a coil is over a N pole, the other
side doesn't have to be over the adjacent S pole. It can be over a S pole a
couple of magnets away. If you try my idea about arranging the magnets so
poles oppose, then the coil can be wound sized so when one side is at the
'gap' between two magnets, the other side can be at the 'gap' between two
other magnets, some distance away. Then arrange all the coils so the left
side of each one tucks under the right side of its neighbor.
You can also 'flatten' the coils, spreading the conductors wider around the
circumference a bit. Don't spread them out so far that different turns in
the same side of a coil span more than about 3/4 the distance between N and
S pole pairs though. This spreading allows you to keep the 'thickness' of
the coils down so more copper is closer to the magnets and there will be
less gaps where there is no copper conductor.
If you ever do want to go three phase, you are going to need at least 3
coils for each magnetic pole, so finding ways to overlap / spread the coils
could be worth the effort.
Three phase will give you smoother output with less 'cogging' when you load
the unit. Or is this the reason you have so many more coils than poles, to
reduce the 'cogging' effect even though it sacrifices voltage generated??
daestrom
