I have the following note in manual for polarization and was wondering why the procedure is different between the earlier 6 Volt A systems versus the later 6 V B systems/regulator models. Just curious.
"On the 8N tractors, use a jumper wire or a flat blade screwdriver to momentarily short between the "BAT" and "GEN" terminals on the regulator. Sometimes they will be marked "BAT" and "ARM". Make a spark and it's done. Make sure to short BAT to ARM and not to FLD. If the three terminals are all in a row, they should be marked B-A-F. BAT and ARM are right next to each other.
The polarization mentioned here should be done any time you notice the generator is not charging, and you just did some sort of repair or maintenance where the battery or generator was disconnected. Often the generator will maintain correct polarity without doing this step, but occasionally it will need to be polarized to re-establish correct polarity with the tractor wiring.
If you have one of the later 6-volt Ford or other tractors, it may have the type "B" system. Look for the regulator terminals to be marked A-F-B. If the BAT terminal is not right next to the ARM terminal at the regulator, this is a type "B" system. The "B" systems take a little more work to polarize. Disconnect the FLD terminal, touch the FLD terminal to BAT, then reconnect the FLD terminal."