Aaah, "the rest of the story"! :^)

What you're seeing here really isn't related to whether it's a 1- or 3-phase alternator. At the most basic level, the
regulators for each type of alternator are the same, assuming the alternator in question produces a DC output. Regardless of
the number of phases, the basic function of the regulator is to sense the DC output voltage, and regulate current supply to
the rotor (armature) to keep the output voltage correct.

The differences between the two regulators you have are more related to 1) details (unrelated to # of phases) in how the
alternators are wired and 2) the fact that the one from the tractor apparently has functions usually not associated with
voltage regulators on small engines, namely the oil & battery warning lights.

Eric Law

"RB" wrote in message ...
Thanks for all the info.

Where I ran head on into this recently was in trying to get an el cheapo
voltage regulator subsititute for a garden tractor I work on for our church.
The dealer wanted $120 for one, and I can buy a number used ones for approx
$20.

However, what I didn't know about was the fact that some of the motorcycle
and boat stuff is for 3 phase.

And, a 3 phase regulator definitely won't work with a single phase system.

Having finally been made aware of this, I wanted to get a leg up on the
problem to maybe be able to identify what I'm dealing with by sight, rather
than having to tediously go back to manufacturers of engines, regulators,
etc.

You guys have given me enough to probably be able to identify single or 3
phase alternators.

I still have only a partial grasp of how to look at any old regulator and
tell what it was made for.
On those, it may be the only way to find out is to ask the company who made
it, or know for sure what it came off of and ask them the phasing of their
alternator.

The single phase regulator I'm dealing with has six wires, but is for single
phase alt. Two of the wires go to the stator/alt, one to the battery, two
are sensing circuits for low oil pressure and low battery warning lights,
and there is a ground.

The first one I bought was an aftermarket regulator for a Harley, and it has
3 wires. Two to the alternator, and one to the battery. When it didn't
work, I started asking around, and found out many of the twin motorcyles use
3 phase alternators.