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From: RB on 27 Mar 2005 13:57
}}} but I've never seen an alternator that had an AC output.
All have had internal rectifier diodes (which would be cooled by the
alternator's fan). Does your regulator provide the rectification? {{{

Right you are. Most of the bigger ones (cars & trucks, etc), have DC
output. And yes, they have internal recifier networks.

The small gas engine ones use a simple one that brings AC out. The voltage
regulator unit is actually dual function. It has a rectifier network, and
then, somehow, purports to regulate. I think the regulation is mostly a
figment of someone's imagination, as there doesn' seem to be anything in
most of 'em except a resistor or two. Anyway, it does purport to regulate
the recitified DC it produces.

}}} they're nothing
but a coil mounted near the flywheel to get their energy from the magneto
magnet. {{{

This is close to the truth, but still misleading. The magneto he speaks of
is simply a ring of magnets glued around in a ring on the face of the
flywheel which rotates past a stator coil to get ac. When we say magneto,
we normally are thinking of the thing that helps make the spark for firing.
This alternator is a form of magneto, but is different not the normal
ignition magneto.



From: Franc Zabkar on 27 Mar 2005 17:11
On Sun, 27 Mar 2005 12:57:50 -0600, "RB" <rbig(a)bellsouth.nospam.net>
put finger to keyboard and composed:

>}}} but I've never seen an alternator that had an AC output.
>All have had internal rectifier diodes (which would be cooled by the
>alternator's fan). Does your regulator provide the rectification? {{{
>
>Right you are. Most of the bigger ones (cars & trucks, etc), have DC
>output. And yes, they have internal recifier networks.
>
>The small gas engine ones use a simple one that brings AC out. The voltage
>regulator unit is actually dual function. It has a rectifier network, and
>then, somehow, purports to regulate. I think the regulation is mostly a
>figment of someone's imagination, as there doesn' seem to be anything in
>most of 'em except a resistor or two. Anyway, it does purport to regulate
>the recitified DC it produces.

I could imagine a regulator consisting of two pulse width modulated
SCRs with some minor support components. The switching noise wouldn't
be that serious in a tractor.

>}}} they're nothing
>but a coil mounted near the flywheel to get their energy from the magneto
>magnet. {{{
>
>This is close to the truth, but still misleading. The magneto he speaks of
>is simply a ring of magnets glued around in a ring on the face of the
>flywheel which rotates past a stator coil to get ac. When we say magneto,
>we normally are thinking of the thing that helps make the spark for firing.
>This alternator is a form of magneto, but is different not the normal
>ignition magneto.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.
From: Jim on 28 Mar 2005 22:26

Franc Zabkar wrote:
> On Sun, 27 Mar 2005 12:57:50 -0600, "RB" <rbig(a)bellsouth.nospam.net>
> put finger to keyboard and composed:
>
> >}}} but I've never seen an alternator that had an AC output.
> >All have had internal rectifier diodes (which would be cooled by the
> >alternator's fan). Does your regulator provide the rectification?
{{{
> >
> >Right you are. Most of the bigger ones (cars & trucks, etc), have
DC
> >output. And yes, they have internal recifier networks.
> >
> >The small gas engine ones use a simple one that brings AC out. The
voltage
> >regulator unit is actually dual function. It has a rectifier
network, and
> >then, somehow, purports to regulate. I think the regulation is
mostly a
> >figment of someone's imagination, as there doesn' seem to be
anything in
> >most of 'em except a resistor or two. Anyway, it does purport to
regulate
> >the recitified DC it produces.
>
> I could imagine a regulator consisting of two pulse width modulated
> SCRs with some minor support components. The switching noise wouldn't
> be that serious in a tractor.
>
> >}}} they're nothing
> >but a coil mounted near the flywheel to get their energy from the
magneto
> >magnet. {{{
> >
> >This is close to the truth, but still misleading. The magneto he
speaks of
> >is simply a ring of magnets glued around in a ring on the face of
the
> >flywheel which rotates past a stator coil to get ac. When we say
magneto,
> >we normally are thinking of the thing that helps make the spark for
firing.
> >This alternator is a form of magneto, but is different not the
normal
> >ignition magneto.
>
>
> - Franc Zabkar
> --
> Please remove one 's' from my address when replying by email.

I am wondering if you have a john deere 317 mower tractor? these came
out with a kohler 2 cylinder air-cooled engine or a 2 cyl onan
air-cooled. either engine has approx. 12 charging coils mounted
stationary inside the flywheel and output alternating current at
approx. 13-14.5 volts. this ac voltage brought out via 2 wires to a
connector plug which goes to the rectifier ( voltage regulator ). the
(vr) has 3 wires -2 ac in & 1 dc out. this goes to a plug which
carries an ignition, lights, electric p. t. o. clutch (some models) &
the charging voltage back to the instrument panel. check all plug
connectors ( at vr , main harness &the plug coming out of the flywheel
area.) if the engine is a kohler, the part # from john deere is AM
106357 which is $42. good luck.
Jim

From: James Sweet on 28 Mar 2005 22:50

> > >}}} they're nothing
> > >but a coil mounted near the flywheel to get their energy from the
> magneto
> > >magnet. {{{
> > >
> > >This is close to the truth, but still misleading. The magneto he
> speaks of
> > >is simply a ring of magnets glued around in a ring on the face of
> the
> > >flywheel which rotates past a stator coil to get ac. When we say
> magneto,
> > >we normally are thinking of the thing that helps make the spark for
> firing.
> > >This alternator is a form of magneto, but is different not the
> normal
> > >ignition magneto.
>

The ones I've seen use the same magnets used for the ignition magneto, the
coil is just mounted in a different location around the circumference.
That's certainly not to say other types aren't in use, most of the small
engines I've worked on didn't have any sort of charging system at all so I
don't have a lot of experiene there.


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