John Dammeyer wrote:
>
> Hi Roman,
>
> What I suspect,  but don't know is that the Regulator also needs 12V
> power to run it.

Unusual.

> i.e. Perhaps one of the two unknown wires is the Alternator Lamp and the
> other powers the unit.  The lamp is on when the alternator isn't
> producing AC and goes out once the alternator is providing more than 14V
> or something like that.

Is there an alternator lamp? That may explain one wire.

> On the power waste type.  That type would also be used for Wind Mill
> Chargers I would guess so that even in extreme wind conditions and fully
> charged batteries maximum load would be provided to prevent overspeeding
> and not burn out some sort of overspeed brake.

Common with small vehicles now too, not that I
like the system much.

> I imagine if I attach this PM alternator to a 1725 RPM furnace motor I
> might see a fairly high open circuit voltage.  That implies too that the
> regulator needs to have either a high enough rating or transorbs to pull
> down the voltage before the input circuit pops.

Expect about 90vac or so with no regulator
connected.

> On a boat it's possible to switch between battery bank A and B to off so
> the  regulator could go out of the circuit briefly while the Diesel
> Engine is still turning.  Catastrophe for the regulator and associated
> electronics on the 12V bus.  I think the term is "Load Dump" and we
> don't want to do that but it can happen.

Probably will be ok if you leave the regulator
in circuit as you change the battery. My book
here describes a similar regulator, uses SCRs on
the alternator output. When battery voltage gets
high enough the SCRs turn on and just short the
alternator ac output, or just the last portion
of the ac wave. Sounds thoroughly nasty to me
but that's how they build motorcycle regulators
these days...
-Roman

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