Jim Land wrote:
budgie wrote in
:


What I'm curious though is how exactly does this thing work? The
armature has no connection at all to anything. I imagine it must
receive power through induction but how is the output regulated? Is
there a trick to manufacturing these? Given there's no brushes or slip
rings I'd have thought all alternators would be made this way unless
there was a disadvantage.

Have you tried Google? Searching on schematic "brushless alternator"
yields a lot of hits, including a simplified description and schematic
of a three phase brushless alternator at:

http://www.ee.qub.ac.uk/power/fyp/pd...e_tlittler.pdf

and more info at:

http://www.pearen.ca/dunlite/BrushlessAlternators.pdf


Interesting topic. In brief, it's possible to make an alternator without
brushes, as follows:

On the same shaft, there are two separate rotor windings. In the case,
there are two separate stator windings.

The first stator gets its current from the battery. Its rotor generates
AC which is rectified by diodes which are rotating with it. This DC is
then wired to the second rotor winding, which is of course also rotating
with the diodes. Hence, no brushes.

This second rotor now has a DC current running through it, which makes it
the field coil for the second alternator. Its stator generates AC which
is rectified by diodes and is wired to the battery as usual.

One way to control the output is to regulate the current to the first
stator winding, which will regulate the current to the second rotor
winding.


Yeah I did and I saw that actually. This one is different though.
There's a single set of windings on the rotor which has a single diode,
though there may possibly be another diode buried at the motor end of
the rotor but looking through the vents I didn't see anything. I didn't
see any diodes in the stator either, though they might be hidden as
well. I have another motor run cap of similar but not the same rating on
hand which I'll try in the generator and see if it fixes the problem to
the extent of producing some power, I'm absolutely certain the original
cap is open but I'm not positive another problem doesn't exist.

Seems nobody here so far has a real solid understanding of how these
work but I'll figure it out. I was just hoping for a nice concise ready
made theory of operation to replace my deductions.