One-Wire Alternator?

euswdwj@yahoo.com · May 22, 2019

Hi All!

My Ferguson TO 35 has a Delco Remy alternator that only has one wire going from the positive lug on the alternator to the battery.

After looking online I'm having doubts that this is a one-wire alternator.

Please help! Is this a one-wire or a three-wire alternator?

The model number on the alternator is:

1102480 61A
6G19-12VNEG

very best regards,
William

rvirgil_KS · May 22, 2019

If it is intended as a one wire it has been rebuilt and the numbers stamped on the case don't necessarily mean anything.

If it has a filler plug over the 2 edge pins it is likely a one wire

If you can rev the engine and it starts charging and regulates output voltage it is likely a one wire.

If it does not begin charging when revved up, momentarily jumper from the output to #1 pin and see if that makes it charge. If so, get a connector plug for the 2 pins and loop #2 down to output of alternator and run a wire from #1 pin to coil side of ignition switch. Put a lamp, diode or 10 ohm resistor in this line or it likely will not shut off

JDEM · May 22, 2019

There is no way to tell for sure just by looking at. If you pulled it apart, got the part # off the voltage-regulator - you might be able to
search the # and find out if it is a "self exciting" regulator or not. That is the only way to tell for sure with visual information.

There are so many aftermarket regulators made and sold all over the world, some part #s won't even show up in a Web-search.

Bob · May 22, 2019

There is no definitive answer to your question based on the info you posted, as it may have been rebuilt or "remanned" one or many times to different "spec's" without having the original part number ground off/obliterated.

The part number you are seeing indicates it would have been used on Chevy trucks from '77-'79 or Corvettes from '75 to '77, and none of those alternators ever left GM/AC Delco as "one-wire" units.

The "one-wire" units are bastardizations of the original Delcos dreamed up and sold by the aftermarket.

John T · May 23, 2019

I have seen so many different supposed "three to one wire" adaption methods its hard to say what you have. I have seen adapter plugs placed over the two small side 1R and 2F terminals and of course, the more traditional method where the 1R is supplied initial excitation. They all obviously still have the one big main rear stud output that charges the battery often via the ammeter.

Put a volt meter on the battery tractor not running and if it has a good full charged battery at rest and stabilized it would read around 12.6 volts. Then start the tractor and rev to a high RPM and ifffffffffff the alternator is working the battery voltage should eventually rise to at least 13 up to 14 + volts subject to voltage regulator. Then if its working and charging and aint broke DONT FIX IT LOL

John T NOT any alternator expert so no warranty

JDEM · May 23, 2019

Just to maybe correct the record here? Bob stated . . ."the "one-wire" units are bastardizations of the original Delcos dreamed up and
sold by the aftermarket."

I do not see how that can be true. Delco-Remy offered one-wire self-exciting regulators on the 10SI OEM back when they were new. So,
either Delco copied the aftermarket people, or the aftermarket copied the Delco people. I suspect Delco-Remy offered it first and there is
plenty of Delco literature to support that. Delco provides custom wire diagrams for adding features like idiot lights with the 1-wire
systems.

I will note that I only see it offered by Delco on the 10SI. Not on the 12SI. Why I do not know since the regulators are interchangible
between those two models. Maybe because the 10SI is the only one that Delco recommended for farm equipment?

Bob · May 23, 2019

That being said, have you ever seen a FACTORY setup using a "self-exciting" 10SI "in the wild"?

AVAILABLE is one thing, but I'm going to venture to guess that they are virtually non-existent in the real world.

It would be interesting to have a part number for the unit shown in the drawing and do a search to see where they were actually used.

On the other hand, hundreds of thousands of the larger-framed brushless Delco "one-wire" alternators have been used on trucks, farm equipment, construction equipment, etc..

JDEM · May 23, 2019

My guess? The one-wire setup is not ideal for most applications because it lacks a separate battery-voltage sensing circuit. Often not an
issue on farm tractors that see limited use and the battery is often very close to the alternator anyway.

Delco did make a point of offering the 10SI for farm tractors and for conversions from generators (with brushes that carried charge current)
to alternators (with brushes that do not).

I used to have part #s for the Delco self-excite regulators. Probably still do in an old PDF somewhere. I think Delco stopped selling them
long ago. Maybe due to the competition from the aftermarket. Last bunch of self-excite regulators I bought were $7 each. Not much profit to
be made there it seems.

John T · May 23, 2019

Bob a few years back I was at a tractor show, maybe it was Two Cylinder Expo in Canandaigua New York (I used to give electrical seminars there), I forget. Anyway a vendor was selling a "One Wire Conversion Kit" for the 10SI which consisted of a wired black plastic cover/cap over the two small side terminals which had one wire down to the big main output stud (2F Voltage Sense I assume) and the other connected to that with a (If I recall been a long time) 140 ohm resistor then to the 1R excitation terminal. At 12 volts that could create a (12/140 + what other resistance) constant battery current drain and 12/140 + other resistance for initial excitation. I cant say for sure that was the resistors value and whether or not such provided sufficient excitation???? I'm NOT saying bad or good nor if it worked, All I can say he was selling them and claiming they worked.

Your remark about "bastardizations of the original Delcos" made me think of that lol Ive seen all sorts of jury rigs on those alternators.

Best wishes

John T

JDEM · May 23, 2019

Here is a 1968 patent on a self-exite regulator for an alternator. I know General Motors and Basler Electric cited the patent with stuff they
used. Cannot say I researched the whole line of patents very closely though.

Traditional Farmer · May 23, 2019

For $60 you can go on ebay and get a great working one wire alternator from DB Electric.I have 10 tractors with those alternators on them,gas and diesels, they work great.Normal start
up they start charging right away.

JDEM · May 24, 2019

I have bought many from DB Electric. The 10SI clones you mention appear to be the same Chinese models as sold here at YT. I just bought a complete change-over kit for my Ford Jubilee for $86. New Chinese 10SI clone with a self-excite regulator, new wiring harness, wide belt pulley on the alternator for tractor use, ignition ballast resistor, and custom alternator mounting brackets. Kind of hard to beat the YT price. If DB gets $60 for the bare alternator - then I figure YT Tractor gets $26 more for the wide pulley, mounted brackets, belt adjuster, wire harness, and ignition resistor. Pretty fair price.

Traditional Farmer · May 24, 2019

Very good price I do buy the double pulley alternators they are a few $$ extra, so it makes lining up the belt easier on some tractors like the Fiats.

euswdwj@yahoo.com · Jun 21, 2019

Thanks everyone for your feedback!

Tested the output of the alternator and it does appear to have been converted to a one-wire system.

Thank you again for your awesome information!

One-Wire Alternator?

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