G'day all,
my 26 Tudor has its original generator still ( original l believe ! ) it may have been rebuilt some time or more in the past 80 odd years, but until Sunday charged at about 6-7.5 (volts)on my digital meter while running the battery at 6.3 - 6.8 volts.
Well its now charging at .780-0.923 volts, and not going any further, the battery side still reads 6.3 volts.
How do l check and or adjust to gain more voltage back out of it ????
Thanks in advance for your suggestions.

Cheers David.

Have you checked the brushes? They might be worn out or the commutator need to be cleaned up.
Norm

G'day Norman, no l haven't checked the brushes yet, something l have yet to attempt, can you give me a brief run down on that, and if the commutator is dirty , how does that effect the generator from charging, at this present time have no idea on this system, a new learning process !!!!

David.

David:

To start with - digital meters just do not give reliable readings when the T motor is operating. the ignition coils interfere with the meter. It really has little to do with the quality of the meter and you can easily get fooled into all sorts of erratic conclusions. I have laboratory grade digital Fluke meters and they are no better. Get an inexpensive analog type meter and use that for your measurements. You didn't mention how much charging current (in amps) that you were reading on the ammeter since that tells a lot. Are you using a mechanical cutout, diode cutout, or voltage regulator on your generator? Let us know what you have and we can help.

G'day John, the guage in the car is where l first noticed the charge rate drop whilst driving on the weekend just gone, on the way out it was showing a charge of about 6-7 amps, l remember some time ago doing a rough comparrison on my digital multimeter to see what the difference was, it at that time showed a very close comparrison from the 6-7 amps on the guage on the dash to 6-7 volts charge at the generator and similar numbers on the battery side of the generator cutout on my digital multi meter.
Does this assist ???
David.

Sorry, should read and type at the same time, Generator cut out is standard ford script mechanical type.

David

David, I think Norm is referring to the generator's commutator, not the timer. Dave

OOOPs.
i have no idea where that is.

David

It soundS like you may need to have your generator rebuilt but before doing that, you may want to clean the copper commutator as it is revolving with a small piece of 600 grit wet/dry sandpaper folded into a long thin shape and inserted through one of the the access holes of the end cap. Sand until shiney and keep it moving back and forth so as not to groove the commutator. This will allow for a better contact between the commutator and brushes. Jim Patrick

Ok thanks thats a job for tomorrow, does the generator pull out without the removal of the inlet manifold, l'm guessing it does.
David.

Digital gages or meters are too sensitive in a lot cases Case in point a new fire truck was deiivered with the pump control panel igital when the truck was in service the panel was a maze of nothing but flashing lites and they had to be replaced with analog gages to know what RPM PRESSURE TEMP FLOW And what was really going on especially at nite Digital is ok for very stable mesurements but not good for fluctuations Too SENS itive

For the record it is not a case of a digital meter being "probably good enough" for a reading. If it were "close enough" it would be fine. The problem is that digital meters have circuitry inside that is very easily interfered with by the radio frequency wave energy that is put out by the nearby T ignition. A digital meter's "sample and hold" circuitry can act just like a scanning receiver. Turn an any AM radio in the garage and tune it off station and then start up your T. Listen to the amount of noise that is coming from the speaker and understand that the same noise that the radio is picking up at a further distance is even stronger in your digital meter under the hood nearer the source of the noise. It makes readings that may or may not be the least bit accurate and using one anyway is often an attempt to make sense out of nonsense. If the T motor is not running then it can be more than accurate enough but I simply don't trust them for any reading when the engine is running. Since there seems to be adequate opinions as to what might be wrong - I shall not confuse the issue further and will let you fellows get on with the fixing job.

You don't need to remove the manifold to remove the generator. First thing to do is to disconnect the negative battery cable at the battery. Second remove the wire from the generator. Third loosen the 3 bolts in front of the oil intake on the timing cover. The heads of these bolts face the front of the engine one of the 3 holds the spring which holds the timing commutator. When you back these bolts out far enough the generator will come out.

Before you remove it however, sand the commutator as posted above by Jim Patrick.

If sanding doesn't fix the problem, you will see 3 carbon brushes which are pushed against the commutator by coiled springs. when these brushes get worn down the springs will not push them far enough toward the commutator and they don't make good contact. It's fairly easy to replace the brushes, and they are relatively inexpensive. If replacing the brushes doesn't fix the generator, it's time to send it in for rebuild or buy a rebuilt generator. Or if you don't think you are up to replacing the brushes, send it in.
Norm

Norman. Thank you for the clarification. I should have told David to start the engine and sand the commutator while it is idling. Jim Patrick

Ummmmmm , thanks Jim .....l think !!

David

Well, what an easy job, pull the cover off the back, check the carbons, give the shaft a good clean and re install, l did however find the that the contacts were some what gummed up in the holders so l degreased them all, cleaned the shaft, will assume this is the commutator as mentioned above, re installed.
Unfortunately the battery is either very flat or on its way out, but during the crank up the needle went to 2 amps so l'm hoping jobs done.

Thanks for your assistance on this first time generator play.

David.

After you get the car started, let us know if that fixed the problem.
Norm

OK , it seems to be back and working, on my digital Neilson mutimeter l am now getting 5 volts from the generator, the battery was just shy of 8 volts when started, and running at just under 7 volts.
My guage inside the car is only showing 1-1/12 amps though ????
My lights failed to turn on but came on shortly after, now on and off when switched.

Hopefully thats the end of that problem.

My contact carbons- 2 large, one was about 1/2"long, the other was about 1/4"long and the small one was as the big one about 1/2"., what is the normal length of these new ???

Cheers for the help David Dare.

If you disassembled the generator you must reset the brushplate null point upon reassembly. If you did this simply increase the charging rate by moving the third brush clockwise as viewed from the gear end.
If you did not reset the null setting do not increase the charging rate to compensate for the low charging rate. Go back and get the null setting correctly set.
About 5-7 amps charging rate should keep the battery fully charged unless you do a lot of driving after dark requiring the headlamps.
New Model T generator brushes are 3/4 inches long measured from the indented portion where the brush spring contacts at 90 degrees to the concave armature contact section.
Ron the Coilman

G'day Ron, thanks for your input, BUT can you tell me what that is, the null point, all l have done is clean the inside and put it back how it was.
How do l increase the charge setting, this part of the car is all new to me, l dont have the book on electrics either, but am interested to learn more on how this generator charges and what can be done to it, whether it is fix it to run or play with it to run better !!!

Cheers David.

David
The best thing to do is get a copy of "Ford Service" book and refer to the generator repair and troubleshooting sections. The brush plate null and charge rate setting instructions can be found there. This book usually has part number "T-1" with the Model T suppliers. It is the best repair book you can have if you own a Model T.
You are welcome to contact me directly if you need further help.
Ron Patterson
modeltcoils@windstream.net

OK thanks Ron.

David