12 V Alternator conversion problems

Hi! I have a 1940 Farmall M. It was converted to 12 volt with a Delco Remy alternator by the previous owner. This alternator has a ground terminal along with the BAT, R, and F terminals. There is no external "silver box" regulator connected to the alternator or the electrical system. The battery was going dead with use of the tractor. There was only one wire hooked up to the alternator (the Bat terminal was hooked up to the ammeter). I read about 12 volt conversions and wired up the F or 2 terminal to the BAT term. Then I wired a warning light from the R or 1 terminal to the ignition switch (on the side that the coil is on). I turn the key on and the warning light does not light. I start the tractor and the warning light turns on. I throttle up the tractor and the warning light glow VERY bright (so bright I think it might burn out soon). Any ideas? Could this have been a one wire conversion and I"ve added the incorrect stuff to this? Could I be missing the silver box voltage regulator??? Should I get a newer alternator or add a voltage regulator? (I think this is a mid 60"s alternator because of the R and F terminals) Let me know what you think... as I"m still reading about this!! And thanks for the help!!
Troy

From the terminals you gave, it sounds like you have the older Delco 10DN EXTERNAL regulator type alternator. If you have a 10DN and wired it as you say, 12 volts to F, then the alt should be putting out all it can. You did not mention the ammeter reading when running or if the ammeter even works. If you have the 10DN it MUST have an external regulator. If you go this route, you need a wiring diagram from a mid 60s GM car or truck to hook it up . Also get the rubber shock mounting kit NAPA sells them) Don't ask me how I know this.

A simpler solution would a 10SI with internal reg. Get a three wire one for about $25-$40. Diagrams to hook up one of these are available on this site. Sorry, don't have the link.

Stay away from the ONE wire setups.

Hi! Thanks for the response. There was no reading on the ammeter gauge before I hooked up these two wires. It just stayed at zero or in the middle. Every time I run the tractor I have to charge the battery to get it to start and then when I shut it off and try to restart it will not turn over so I have to put the charger on it again. That makes me think the alternator isn't charging. When I saw the terminals on the alternator I thought it might not be a 10SI. From my description is this set up as a one wire setup? Will going to the 10SI make it a three wire setup? Seems logical to me... Thanks again!!
Troy

A 10DN will not work as a one wire setup.

Going to a 10SI alternator does not automatically make it either a one or three wire setup. Normally as installed in GM vehicles, the 10SI is a three wire setup. However a 10SI can have a special regulator installed in it so it will function as a one wire setup.

Down side to the one wire setup is the engine has to be revved up to turn on the regulator and make the alternator start charging. After that, it will charge at idle. The three wire will start charging at idle.

YOU CAN NOT ASSUME what the OP has. Some integral regulator GM alternators have BOTH the 1/2 numbering AND the R/F terminal numbering on them.

Did it EVER work? Or did you get it in a non-working condition? If this alternator is old enough that it could be "either" external / internal, only sure way I know of is a good clear picture of the connector/ rear of the alternator, or tear it apart and see if there's actually a regulator in there.

I don't remember anymore, but I'd think that if this is integral AND if you have a shorted "diode trio" that could cause a similar problem.

The only real difference between aftermarket "one wire" and "three wire" alternators is the regulator itself.

The 10DN alternator , designed for an external regulator, has the plug connector in the REAR of the alternator with the terminals arranged like this [l l}.

Very common when using an external regulator 10DN, is to use a 60's Chrysler mechanical alternator regulator with two terminals.
One regulator terminal is connected to switched power (Ignition switch) and the other regulator terminal is connected to the alternators F terminal. The chrysler regulator is a little black metal box aprox 1.5 X 1.5 X 2 inches.


The 10SI type alternator with built in regulator, has the plug connector in the SIDE of the alternator with the terminals arranged like this {- -}.
Which do you have ??

That did not come out right. 10 DN plug terminal in the REAR of the alternator with the terminals arranged like this. {I I}

Actually, 'he' can assume anything he wants, but it might be wrong or maybe right, but he can still assume. Perhaps he shouldn't assume.

Anyway,
10-SI


10DN

Hey guys! Thanks for the help!! This tractors charging system has never worked. All I did was to add the two wires from the R and F terminals (like it shows on the wiring diagram for 12v conversion on this and other websites) after assuming that it was a 10SI and that it had the internal regulator. The R and F terminals on this alternator are aligned like (II) and are on the rear of the alternator. I actually have three 10SI alternators (from a 79 blazer, and an 84 monte carlo) sitting in the pole barn, so I'm going to install one today and see what happens. Thanks again for the help! Great website and forum!!

I have installed self exciting regulaters on a few of my alternators,The downside is that you have to rev them up to get them started then they will charge all day .

(quoted from post at 07:59:02 01/22/10) The R and F terminals on this alternator are aligned like (II) and are on the rear of the alternator. !

Click to expand...

What you describe absolutely identifies it as the older, "external" regulator type unit

(quoted from post at 07:20:10 01/22/10)
Actually, 'he' can assume anything he wants, but it might be wrong or maybe right, but he can still assume. Perhaps he shouldn't assume.

Anyway,
10-SI

10DN

Click to expand...

That's some good stuff Jmor but what I was referring to is the oddball---there exists a newer style frame that is numbered BOTH 1, 2 and r, f because some were made for EXTERNAL and some were made for INTEGRAL regulators

I wasn't able to find a good pic, so I cropped the one from here:

http://www.jeepforum.com/forum/f8/ac-delco-si-alternator-wiring-oddity-where-your-excite-wire-589343/

Notice that this is INTEGRAL, id'd by the "inline" - - plug as opposed to the "R F" connector 1, 2. But ALSO note that the casting is set up for EITHER, not the R and F markings at the bottom. You can convert these back and forth merely by changing the brush holder/ hardware



By the way, there's a wealth of info to dig through right at Delco Remy

http://www.delcoremy.com/Manuals.aspx

Hey there again guys. Well, I changed the alternator to a 10si that I had laying around here. I had to put the charger on it to get it started as the battery was almost dead and it wouldn't turn over. I turned the key on and the light came on. I started it and the light went out and the ammeter showed a charge! The needle was about halfway up the gauge on the charge side, but that would be expected since the battery was pretty low. I have it on the charger now. Once again, thanks alot guys! It would have taken a lot longer without your help!
Troy

Thanks for telling us how it worked out.
Always fun to switch on a project and watch it work for the first time.
Don't toss that old 10 DN in the garbage, the rotor will work to rebuild a 10SI.

One tip for those using a "1 wire" Delco. Buy an alternator with the small 37 amp stator or assemble your own, aftermarket stators are cheap.

37 amps is more than most old tractors will ever need, and will self excite at aprox 1/2 the rpm of a 61 or 72 amp "one wire" alternator.

Most of those old tractors came with a 20 amp generator.
A 37 amp Delco alternator puts out almost twice the watts that of the old generator, four times as much if the generator was 6V.