Polarizing generator

I have a 1953 Allis WD with the original 6 volt pos. Ground. It was charging until i replaced the battery. I am. Not sure how to polerize it. The Gen. has a cut out one wire going from cut out to in side the gen. The other wire from the cut out back toward the battery box then ther is only one post on the gen body back from the cut out that wire goes to the battery box as well . Any help would be great thanks

I am not sure which is the F or the A terminal as they ar not marked . I have two post that the cut out is attached to then one single terminal that sets back from that

There are only two wires that go to the generator.  As the other post said, from the A terminal on the generator to the cutout and then from the other post on the cutout to the ammeter.  I don't remember how the cutout is marked..maybe A and BAT?  Have to have those hooked up the right way as well.  The other wire from the generator goes to the F terminal and it goes to the resistor on the light switch.  The terminals on the generator are marked.  Like the other post said, may just be hiding under paint.

To polarize just jump across the cut out relay momentarily. Both posts are marked A or F. You might have to buff off the paint to find them, but they're there. Every tractor generator I've seen the posts are the same size. Do what Doug says and ground the F terminal at the generator and see if it comes alive.

I am kind of in the same boat.  My C has not been charging because the cutout had a busted wire.  I changed the cutout and still it was not charging so I went in search of info and landed here and signed up.  After reading this thread I did the wire from the battery to the A post on the generator and Vaa Hoo it was charging---- for a while.  Then the needle started bouncing and went to discharge.  After about 10 minutes it started to charge again for a bit and then discharge.  Is this normal??  I've had the tractor for many years as it has a woods mower deck under it that gets weekly use.  I've just been putting the charger on it when I was done but I finally got tired of that dance.

Edited by Super44 - 06 Aug 2017 at 5:47pm

Not sure what "F needs to be pulled low" means.  When the tractor was running I tested the battery and got nothing.  With the tractor off I got 6.32 volts at the battery. I am very new to this kind of issue!!

Edited by Super44 - 06 Aug 2017 at 7:12pm

There are two ways for a manufacturer to wire a generator field, one connects one field wire to the A post and then grounds the field direct or through a resistor to control the voltage. the other connects one field wire to the generator shell to be grounded by the mounting bolts and then the regulator connects the field wire to the A wire direct or through a resistor to control the generator voltage. Generally AC used the first connection but other users of generators used the other connection.

With a working regulator the generator voltage should be 7.1 volts for a full charge. Lower means not charged, higher breaks down the water in the electrolyte requiring regular refills with distilled water.

Gerald J.

Is the box with the ammeter and light switch grounded securely or is it only slipped into the holder?

ETA: Is the light switch itself secure in the box?


Edited by DougS - 07 Aug 2017 at 9:53am

Short the F terminal to ground while the engine is running. Have someone watch the ammeter while you do this. If the ammeter shows that it is charging, the problem is still somewhere in the F circuit. Possibly the light switch resistor. If it shows a bigger discharge, either the battery somehow got installed as negative ground or the ammeter got wired backwards.

As a last resort measure the voltage on both sides of the cutout. If you're measuring 7-ish volts from the generator but not out of the cutout, your cutout is bad. If your generator shows nothing to the cutout, take the generator to a shop and have it checked.

One last thing: Is the cutout grounded securely to the generator?