Several times I have read on this forum that when the battery is disconnected from the electricfal system the generator has to be repolarized. I want to add a battery terminal switch on the negative terminal on my 6V positive ground system. If I do this, do I have to polarize the generator each time I use the switch?

It should not be necessary.

"Several times I have read on this forum that when the battery is disconnected from the electricfal system the generator has to be repolarized" FWIW you havent read that from me!!!

NOT SO WEEDHOPPER

As a matter of fact, if your Cutout Relay or Voltage Regulator is working properly, which they usually are, each time the tractor is shut off the generator is disconnected from the battery. The cutout when open breaks/opens the circuit from the batterys hot ungrounded post via the ammeter to the genny because otherwise the battery would quickly back discharge via the gennys brushes and armature. The fact its (batteries) other grounded post is tied to some huge hunk of rusty iron (tractors frame) dont matter as (unless a short) there no current path

Soooooooo if what you quoted was true, you would have to repolarize the genny before each time you started the tractor back up, because the battery was effectively out of the electrical circuit after the tractro was shut down.

Soooooooooooo when do you need to polarize???

MOST IMPORTANT AND REQUIRED: If you changed battery polarity and BEFORE you start the tractor.......
If the armature has been removed form the genny and its sat there a long time Id polarize it before starting just to be safe..........
If the genny has sat a long long time Id probably polarize it just to be safe.........
When you buy a new VR it has instructions to polarize the genny but they do that to make sure you dont start it with a batetry at opposite polarity then the genny adn do harm to the new VR

If you just want to, its your tractor to do with as you please, re poalrization dont harm so go for it BUT ITS JUST NOT TRUE EACH TIME THE BATTERY IS DISCONNECTED YOU NEED TO RE POLARIZE THE GENNY. Whether or not it needs polarized has nuttin to do with if you removed or left intact a battery cable when you shut her down provided you re connect at same polarity

NUFF SAID, if I missed anything hope the other fine gents will add to this

John T

no, it's a myth mostly.

every time you shut your tracto down, the cutout opens.. and thus 'disconnects' your battery from the armature of the genny..

if the genny sets a looooooong time without being run, I'd repolarize it.

if you swap polaritiies, I'd repolarize it.

if you take the generator apart, especially if replacing parts, especially any work on the field pieces, I'd repolarize it.

if you 'drop' or bang on the genny a bit, I'd repolarize it.


repolarizing it won't hurt anything.. you could do it every day.. it's just not repeatedly needed in normal use situations..

soundguy

I will add that it is a good idea to polarize it every time the generator has been removed and reinstalled. Polarity can be reversed by testing it to see if it will motor over with a battery connected. Any time one is taken to a repair shop to be tested, polarity can happen to end up either way.

The generator has residual magnetism in the field coils. It stays there (usually) unless that generator gets pulled apart and the armature gets removed. The armature serves as a "keeper" for that slight magnetic field. When you polarize, it's usually done for one or two reasons. To correct a magnetic field that is the wrong polarity, or to restore one that is no longer there.

Same goes for magneto magnets. They stay charged almost forever when a magneto is all together. Take one apart though, and remove the magnet from the case, and it will go dead unless you stick a "keeper" on it. Any chunk of metal will do.

When they say "residual" think back to your elementary school science days where you rubbed a steel nail on a magnet, and the nail became a magnet.

Nope ... that is false.

My grandpa's H sat for 15 years without a battery in the inclement temperatures of midwest Michigan outdoors.

It was just this fall I bought a battery ( not to mention a BUNCH of other stuff ). I rebuilt the carb .. and ignition setup just this fall before turning cold here and it literally scared me when it touched off.

I never touched the generator or regulator and much to my relief .. everything was still working and drawing a charge.

The ONLY time we ever had to polarize is when we changed out the actual regulator itself.