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.