Alternators Re: phase conversion

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: dave pierson <davep-at-quik-dot-com> 

 >>> why not just have a large electric or gas motor run a homemade 3 phase

> > alternator? getting the rpm's right for 60 hz might be a bit tricky, but
> > it'd work even if ineffecient.
>
>It's a little more complicated than that.  I have already built such a unit.
>It's been nearly a year, so I don't remember the details, but it only put
>out something like 2 volts.  Something has to happen inside the alternator
>to get the magnetic field built up properly.  Someone told me to put a DC
>current over one of the legs for a minute or so to kick start the magnetic
>field, but that didn't work either.

    ??

    An alternator, as such, has a rotor, which must be powered with DC,
    or, for small, units, a permanent magnet rotor may be used.

    'putting DC into one of the legs' is strange.

    An _induction alternator_ is a separate beasty, which requires
    external AC excitation.

    best
     dwp