[AT] Generator to alternator conversion, this time on the Super M

[Dean Vinson]

Several weeks ago I'd posted about swapping an alternator onto my JD 3020, a
process which ended up with me having a spare 1-wire alternator on hand
because I'd rushed into things on the 3020 without taking time to really
study what that tractor needed.   So I'd figured "Okay, now that I'm an
expert on alternator conversions and I have this brand new unused 1-wire
alternator sitting here, I might as well swap it onto my Super M-which has
never charged very reliably either."



In hindsight my self-proclaimed "expert" designation might have been
slightly optimistic.   But I did finally get the Super M swapped over, and
it looks good and works well.



I replaced the original generator mounting brackets with Steiner's IHS829
bracket kit, which fit perfectly, and also used Steiner's ABC1426 1/2" belt
pulley.   Took a couple of trial-and-error attempts to get the right size
belt figured out, but I ended up with an A33.


Seems like the default "clock position" of all the Delco-type alternators is
the 3 o'clock position, which on an M-series tractor puts the little wiring
plug a fraction of an inch away from the inside of the hood.  A 1-wire
alternator doesn't need anything plugged in there but it still seemed like
asking for trouble to have it on the side, since the little rubber cap could
get loose and just drop off, and I thought it'd be easy to change the clock
position to rotate that plug up to the top.   (I'd done that on the 3020 and
it was easy).   But I wasn't paying close attention and ended up screwing it
up, pulling things apart that shouldn't have been messed with and which
according to some YouTube videos would not be easy fixes.   So much for "I
might as well swap this onto the Super M."

So I changed course and went with a typical remanufactured Delco 10si 63-amp
three-wire alternator just like the one I'd put on the 3020, which was
inexpensive and on hand at a local auto parts store.   The three-wire of
course *does* need the wiring plug on the side, so I had to change the clock
position on the new alternator also, but it was easy and straightforward
just like it had been when I did it for the 3020's alternator.



60+ amps is a lot of power so I replaced the original ammeter with a 60-0-60
IH-labeled ammeter from Precision Tractor Parts and ran two parallel #10
wires instead of just one from the output terminal through the ammeter and
to the battery cable post on the starter.  In hindsight the OEM ammeter and
a single #10 wire would likely have been fine, since the actual current draw
as indicated on the ammeter (even after cranking the engine over for a bit
on a very cold day) looks like it peaks at about 20 amps and fairly quickly
drops from there.



Because it's a three-wire rather than one-wire alternator I used Brillman's
B3000-001 alternator wiring plug with a diode in the exciter terminal wire,
which keeps output from the alternator from backfeeding the tractor's
ignition circuit and preventing you from shutting the engine off.   I used a
heat-shrink butt-joint crimp connector to splice that exciter wire into the
ignition wire coming to the coil, which was right there handy.  (Ignition
wire + exciter wire on one side of the butt joint, and ignition wire by
itself on the other side.)



The "GEN" warning light on the 3020 serves that same function of preventing
the alternator's exciter wire from backfeeding the ignition circuit once the
engine is running, I think because so little current passes through the bulb
filament, but the Super M doesn't have any such light.   I thought about
adding one in the switch box where the fuse holder is, but figured I'd
already spent plenty of time and money fiddling around with this project.



Finished assembly fits under the hood with just a little bit to spare, and
it's nice to see that ammeter needle move as it should.



Dean Vinson

Saint Paris, Ohio







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