Out of the blue one day was greeted with a GEN light in the old Ford that did not go out after engine start. The fault was determined to be somewhere in the regulator, proved out the generator to eliminate that, though went ahead and serviced the generator anyway as winter is coming on. The offending regulator is a Motorcraft GR-268 service replacement purchased NOS a few years ago. Worked fine till a couple weeks ago. What happens, is the cutout relay will not close when the generator starts charging. Worse, even if the cutout is manually closed, there is no charging when engine is revved. Swapped in my spare regulator for troubleshooting and it worked as normal before and after generator rebuild, with the exception that the output voltage is pretty high. I probably &@$cked with it years ago. Generator set points are higher on average than alternators, but I'd have to get into the procedure pretty deep to be sure and get it adjusted properly. Anyway since 1 is none and 2 is 1 picked up a spare regulator at NAPA - part # VR412SB - Took a day to arrive but it is good ole U.S.A. made. It too works fine. So what happened to the first voltage regulator? Any ideas? They don't ordinarily need any readjustment. Usually, or often maybe, it's the cutout points that stick closed and cause battery backfeed into the armature. Everything looks good under the cover, no burnt or broken windings. Every once in a while I would carefully file the cutout points to remove crud. I couldn't find any specs for GR-268, so I'm not sure of the exact air gaps for all the relays and that. I'd sort of like to figure out what went wrong with this regulator though.
Your broken Motorcraft GR-268 regulator must be your favorite regulator for your car. Sounds like you have the problem already remedied, new NAPA regulator and all is fine.
I answer your question, but the old MoToRs manuals have a section on rebuilding and setting up regulators. Even in the 50’s they have a note along the lines of cost to replace, etc. and suggest just replacing them.
Yeah, there are some tests and specs, but they are for original Ford regulators, they are slightly different internally and adjusted differently. I can't assume a .052" armature point gap (or whatever) is the same. I can't find any specific info on the GR-268 in terms of a manual or specs.
I've been meaning to do that, I did find some generic info on measuring resistances. They want that stuff gets unsoldered from each other though. The cutout is so simple - voltage applied, electro-magnet closes points. What could go wrong?
That's why I suggested comparison tests....don't disconnect anything on either one, measure resistance between everything and everything else on both regulators, see if the readings are substantially different anywhere.
Huh. Well the very first thing tried shows about 25 ohms and beep continuity from the movable contact arm to regulator base. The defective unit doesn't read anything, no beep, nothing. So it isn't surprising it doesn't work. I guess. I don't know "why" though. Maybe one of the wirewounds burnt out. I doubt it, but maybe.
OK, alongside or inside the real heavy wire coil turns on the cutout, is real fine gauge magnet wire. Maybe that is broken inside. I've rewound oscillator coils on radios, but I'm not sure I want to sign on to this. I'd replace the cutout with a Diode, but I'm not sure it would work in this case, it didn't seem to charge at all when closing the cutout points manually.
Bit off topic but I have a diode cut out on my Model A. Granted it is 6V but you should be able to replace the cut out with a diode and have it work. Mike
My auto electrician adjusted mine years ago, - said sometimes they need it. - I have no idea, but it worked afterwards for a while, then some time later I replaced it…..
Right, a diode would have a forward voltage drop of about 1/2 volt, so that would need to be compensated for by re-adjustment at the voltage relay. But when troubleshooting, there was no charging even when the cutout was closed manually.
This is on a Ford right? if so it should be a "B" circuit system, GM and most others use an "A" circuit. The difference is how the field is excited. As I'm sure you know, the field needs to have current flowing through it to make the magnetic field to produce current in the armature. The "A" circuit regulator connects the field windings to ground to complete the circuit, the other end of the field winding is connected to the armature winding inside the generator. The "B" circuit regulator connects the field windings to the insulated terminal of the battery. I can't say positive or negative because I don't know if your car is pos or neg ground. Anyway the other end of the field is connected to ground inside the generator. So, you tested the system to prove the problem was the regulator and I'm sure you did that by connecting the field wire to battery terminal at the regulator, this made the system charge. So now we move on the the regulator you are troubleshooting, with it hooked up and engine running, it will not pull in the cut out relay right? And when you push the cut out contacts together it still will not charge, right? Since the generator had output when you first tested the system, I would say this regulator is not completing the field circuit. That circuit goes through the voltage and current contacts and and connections that would connect that terminal to the battery terminal, most likely riveted connections.. I would look in those areas. Also, I guess it could be any connection from the armature terminal through the cut out relay or even the cut out coil it's self. This would be if the generator is charging but that current is not getting to the battery. Most cut out relays have two windings, one in series and one parallel, so don't let this fool you when testing. I don't think you need to polarize the generator when just replacing the regulator as the field poles are still magnetized the correct direction. one other thing, when swapping regulators around there is a difference in positive ground and negative ground regulators although they may work in place of each other. I think the contact points are made of different material to reduce metal transfer from one point to the other.
Actually I swapped the spare regulator in, and everything was groovy. Decided to disassemble the generator and inspect everything after that. NOS armature, bearings, brush plate, brushes, all that stuff. That is correct. I call it the "Cut In" relay, because it won't. Yeah, it's a mystery to me, but that ain't too tough. Could incorrect cleaning of the contacts do this? I was pretty careful to do this once or twice a year. Maybe too careful? Could a layer of skunge on them prevent the field from getting happy? There is no continuity between the copper cut-in arm and regulator base, the way there is on functional regulators.
My experience is that the regulators you get now just aren't the quality of the old ones. In the last 25 years I have had 3 regulators go bad on my 57 T-Bird. They all exhibit the same problem, the cut-out relay just won't quite close. Most of the time, if I manually close the cut-out relay it will charge and continue to charge until you shut the car off. Then I'm back to the cut-out relay not closing. I've re-adjusted the relay, checked generator output, checked coil resistance and taken failed regulators apart. I haven't found a problem. In each case, a new NAPA regulator solves the problem. What I did notice with the first and second failure is that revving the engine would sometimes get the relay to close and put the charge light out. The last one just flat quit. I seem to get 4 to 5 years out of them. The one on the car now is about 5 years old and still working.
Huh. Well so long as it isn't a personal hygiene issue. I'd heard the repro or modern units weren't quite excellent, so I searched out a NOS unit from the 1970s, figured that might hold up better. Maybe not.
Guess it would be interesting to know what the failure mechanism of the cutout might be. Maybe the electromagnet core is losing its mojo for some reason?
About cleaning the contacts or not, I know many thousands of regulators have worked a good long life without regular cleaning, and my thoughts are that you are doing more harm than good here. I understand that one or the other contacts are made of a different material so metal transfer will be kept to a minimum, maybe this different material is just a coating and you may be sanding it off? I don't know. Also, I don't know how you are cleaning them but I think it is recommended to use a special file. I would think this is so you get a flatter truer surface and sometimes cleaning with sandpaper could leave small specks of sand that prevent good connection. About the copper arm not connected electrically to the base, you will have to look at it to see if it looks like it should be. There many different ways they make these so if you follow logic you can figure out what is needed for it to work. Like I said before, on a "B" circuit Ford system the field wire needs battery potential (not sure if you are pos or neg ground) to excite the field. So make sure it there is a path to this point when both voltage and current regulators are closed. As far as the cut out /cut in relay, it has two windings, one that is from the insulated terminal to ground, (very fine wire) this makes an electric magnet as you know and when the voltage is high enough will pull the contacts together. It also has another winding (very thick wire) that is connected in series so that the current that flows from the armature to the battery must go through it. This increases the magnetic pull to really keep the contacts tight. Anyway, I have followed your posts before and you know your electrical stuff so I'm sure you will come to a conclusion.
i throw all that stuff in the scrap heap . one wire chevy alt. are the best invention ever ! the exception being ny 50 dodge 30 yrs. not a problem .
Yeah, I've read the manufacturer and shop manual docs on cleaning contact points, sandpaper is considered a huge no-go. It might get you going again from the side of the road but it tends to trash the regulator points. I mostly wanted to try and avoid the cut-out relay contacts from sticking closed, this has mostly been my experience with the voltage regulators. In this condition, the battery backfeeds into the armature when engine is shut off and cooks it. The regulator that does regulate, shows about 25 ohms continuity from the cut-out arm to regulator base, while the inop regulator shows an open. Maybe the fine cutout winding is roasted or something.
Yeah, I know that. EFI, electronic ignition, disc brakes, alternators, air conditioning. Lots of good inventions and upgrades in 70 years, might as well scrap heap anything not made in the last 20 by that logic.
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