Not all voltage regulators are internal to the alternator, and external regulation is sought by those wishing to properly and more quickly charge deep cycling batteries. Many modify internally regulated alternators so an external regulator can control them instead.
A Stock Leece-Neville 8MR Alternator Many boats, both power and sail, come equipped with, or have have used, the 5" small-case Motorola/Prestolite/Leece-Neville style alternator. There are literally thousands of these alternators out there. Even large Caterpillar and Cummins engines have used the
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I'm running external regulators, and temporarily have 3 decimal digital voltmeters on the field output terminals of my adjustable external regulators
I was expecting weird results due to the PWM, but they respond as expected.
I have some snap on ferrites I could use, but the system voltage I command the regulators to achieve, seems rock steady throughout most rpms, as long as batteries are not severely depleted and can suck up more than alternator can make at that rpm.
My first brief test of field current, i wanted to see if the external regulator put out constant 12v and limited amperage to rotor, but found amps increased with voltage, above 4.5v anyway, where my V meter at the time turned on.
The more recent test I did not twist power and V sense leads together, but put V sense on field output terminal and can see the V meters when driving.
I see as little as 1.7v when the alternator only needs to make 9 to 13 amps required to run my engine, with no additional loads turned on, and fully charged batteries.
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the lower the rpm the more field voltage applied.
My Chrysler alternator has a rc-50 capacitor. the ring terminal goes over + output stud and the other hole attaches it to alternator casing( ground)
My Nippondenso alternator does not appear to have a capacitor, though I did not remove to look underneath the rectifier.
My chrysler alternator was a lifetime warranty reman. poorly reman'd. The slip rings were installed at the wrong height, the lower brush was touching both sliprings. and failed when the brush wore to touch the spot between sliprings. Surprised it worked as long as it did.
I modified brush holder to lower brushes, and honed the sliprings. They were badly out of round, and had likely been when I accepted it as a warranty replacement..
Once they were round, I polished them with 1000 then 1500 grit sandpaper wetted with Caig Deoxit d5 and never knew copper could glow like that.
I was spinning rotor to hone slip rings using a wire wheel on alternator fan, using an angle grinder speed controlled by a router speed controller.
I wonder if such a slip ring honing/polishing, can significantly increase brush life.
