Generator Troubleshooting

Hi folks, I know this topic has been beat to death but I have a question I'm hoping someone can help me with. This is on my 1946 Farmall H
with a 6V + ground system. A year ago I rebuilt the engine and put a whole new wire harness, new 6V battery, new 6V regulator, and I had a
local shop rebuild the generator. When I first got the system up and running it ran and charged great, charged the battery, + charge
showing on the ammeter, lights nice and bright. After about a month or so I noticed my headlights getting dim and the ammeter no longer
showing a charge, but now a discharge. Basically it stopped charging. I started going thru the troubleshooting guide posted on here
(link below). The first test is to remove the genny main and field leads and start tractor and run up to 3000 rpm genny speed (I assume is
full throttle). According to this guide I should get 2-4V between Main and ground. What I am getting is increasing volts with engine
speed...starting around 0.5V and topping out at 1.5V at full speed. If I read th eguide right that means I have "c). Voltmeter reading
rises with engine speed = short circuit between Main (or D) and Field (or F) terminals. Field coils defective."

I want to just verify if that is the correct conclusion. When I took the genny apart I tested the field and armature and seemed to pass
every test. Let me know what you think.

http://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=farmall&th=811423

With the field terminal grounded to bright shiny metal, and the Arm disconnected, the generator output should be way above 6v at 75% throttle, maybe 13 volts (measure with an analog (needle type) volt meter, or really good digital with averaging). Another way to test the gen only is to disconnect it, and take the belt off of the pulley. Jumper with a 10 gauge wire or jumper cable, from the bat negetive to the arm terminal on the gen. It should run like a motor. Not real fast, but start and spin. If while it is spinning, you ground the field terminal, it will slow way down. If neither or only one happens it is the gen that has issues.
If it passes this test, reconnect it to the arm and field of the regulator. This tractor is of a vintage that is just prior to generators being equipped with a voltage regulator, so I assume it has a real VR, and not a cutout. (they look the same)
If a true VR, the light switch should not be connected in any way to the field wiring. On the cutout equipped tractors a wire from the light switch was used to control output by operator choice of L H Dim Bright switch positions. L and H were charge positions, and connected the Field to a resistor on the light switch for low chage, or directly to ground for High charge. There were tractors sold with no lights, these tractors used no switch, and connected the field terminal to the F terminal on the cutout. This was a connection to a resistor that gave the tractor a steady low charge. (no light switch)
With a true VR, the light switch generator wire (not the light wires) must be disconnected from the system. Let us know what you find. Jim

Justin, here's my Charging System Troubleshooting Procedure, give it a try.

http://www.ytmag.com/cgi-bin/viewit.cgi?bd=jd&th=458743

If you dead ground the Gennys FLD post when shes running that should make it full max charge (if cutout relay is working). If it charges then but NOT otherwise, the VR is bad or its not well grounded (for a VR system) and if a LHDB light switch manual charge system, the FLD isn't getting a good ground via the LHDB switch or the switch isn't well grounded.

Give it a try and let me know.

John T

Thanks for the help. It originally had a cutout and the LHDB switch setup. When I redid everything I switched it to a 6V + ground VR and the LH on the switch no longer does anything (no wires attached to these anymore). I do still have dim and bright lights from the switch. I followed the wiring diagrams very carefully and like I said it worked great for a month or so. I will try these tests you've guys mentioned and get back to you. Thanks again.

John...just to be clear I can leave the gen to VR wires (Field and Arm) intact while doing this test? Just add a wire from F to a good ground...

Thanks!
Justin

Simple test while running ground the field if that makes it charge the reg is bad and if it doesent charge the gen is bad this assumes all systems are ground even lite sw way to check is OHM meter one lead to batt ground use other to go from componet to componet..

Wasmthe regulator made for replacing the cut-out make sure the reg is made for the Delco# on the Gen

Yep, the VR is supposed to ground the Field anyway but if its not (bad or bad ground) no harm in temporarily doing it manually. Likewise, the LHDB is supposed to on those systems and no harm in doing it manually.

If it charges with FLD grounded but NOT otherwise, VR is bad or not grounded or LHBD isn't connected or grounded.

If no charge with FLD grounded you can next by pass the cutout relay by jumping BAT to GEN/ARM so if no charge then when running, VR is essentially by passed and out of the equation so genny must be bad or a wiring or other problem.

John T

When you replace the cut-out with a gen you dont run a wire to the lite sw assy from the field so you did rite by not having a wire to make the LH sw do anything.

I bought a regulator that was for 6V + ground systems, I cant recall if it was specifically for the Delco generator or not. I was under the impression that it just had to be a 6v + VR?? Is that not so?

ok so I only had a few minutes this AM before work to check things out. I started the tractor and grounded the field and ammeter went to +8Amps! So this sounds like a VR issue. However when I turn on the headlights the ammeter goes -5 (low) and -8 (high). With field wire removed the High beams are showing s -20A drain. So this is definitely an improvement but shouldn't it be able to keep up with the headlights? I need to pull my fuse box cover and double check my wiring in there. The image shown is how i have this wired. The battery is currently low on charge so maybe that is also part of the issue. Just barely had enough juice to crank it over this morning.

Yes. It probably has a three brush generator. If so the third brush can be moved closer to the fixed brush on that side. As close as possible is best. This will increase the charge rate some. If extra 9or higher wattage) light bulbs are used, it might not get there. Jim

Yes I have a 3-brush generator. So from what I gather online this means I either need to stick with a cut out or use a conversion kit in order to use a VR. Can anyone point me to a clear explanation of how to do this? Thanks.

If the three brush third brush is adjusted as my earlier post, yes you will probably need a later gen from a 53 H Stage 1 or 2 Jim

The regulation of different generators is a bit tricky. The field current on some gens is greater than the rating of the voltage regulator points. The real limitation on the early generators was their low output when working as hard as they can. 15 to 18 amps is about it. later IH gens (which are readily available) can be depanded on to make 25. Jim

OK I moved the 3rd brush as far as possible and now I'm getting 20 Amps with lights off and still about 8-10A with lights on high. So it seems my generator not only is working but is a pretty strong one.

However there is no tag on my generator. I looked everywhere I could including under the VR. Is it safe to say that I can upgrade to a VR using the VR1813 on ytmag? It says it requires the conversion kit VRK1815. Interestingly you can get those two parts in a package under the John Deere section:
VR Upgrade Kit

If you are charging well, check the voltage at 3/4 throttle across the battery (needle type volt meter or expensive digital, or the readings will be all over the place.) Voltage should be 7 to 7.2 volts. If more than that the VR needs adjustment, or replaced. If the VR was bypassed, and it doesn't work without the bypass, and the regulator is well grounded, replace the regulator with one to fit a 1952 H. It will work. Jim

Thanks Jim. This was with the field wire grounded. The VR is well grounded. Everything else is in order but there is no charge unless I ground the field. With the field grounded I *think* I was getting over 7 volts but will recheck. Either way it seems I fried this VR. I talked to the folks at Steiner tractor and they tell me that I need to use this voltage regulator conversion kit to use the VR with the 3-brush generator. This is basically just a resister in the field wire I think, replicating the LHDB switch function. Not sure I'm 100% convinced of how this will work but we will see. I can't seem to find any VR for a 1952 H. the VR for the Super H is the same except for a flat base. It still requires the conversion kit.
Untitled URL Link