12 Volt Postive or Negative Grd. Which is best?

Anonymous-0 · Jul 27, 2008

Going to start over with my ignition and charging system.Its a 12 volt 350 utility tractor with a generator.I do not know if 12 volt is original but want to leave it that way.I would like to use new Electronic Ignition and new voltage regulator and new coil. What else may I have to do besides possabley changing the polarity of the charge gauge? Thanks.

GA Dave · Jul 27, 2008

You may want to get a alternator if upgrading. Most all of them are negative ground. Here's a good article on changing from 6 to 12 volts but is a good guide if changing from a generator to alternator. Search the archives on this site for information on electronic ignition systems. Click below. David........http://www.ytmag.com/articles/artint131.htm

GA Dave · Jul 27, 2008

BTW, when using a GM (and maybe others) alternator no voltage regulator is needed. David.........

Anonymous-0 · Jul 27, 2008

12v gens are easy to find at tractor repair shops ect just make sure when you get a regulator for that gen you use the ground thats usually stamped on the underside as in thiose days both grounds were used. If you find an original 12v for I-H it will have a red Delco Remy tag. Those were neg ground. It is a good idea to get the regulator for that Delco# so it works better. The 12v thingy is without the biggest topic on this site.

Jim Becker · Jul 27, 2008

According to the Parts Catalog, the 350U was positive ground, even if 12-volt. If you currently have a 12-volt generator, it is likely that what you have is pretty close to the original equipment. In that case, I think it would cause less confusion later on to keep it in the stock configuration (positive ground). Most of the system won't care which way it is grounded. Regulators used to be specific one way or the other but most new ones now are probably the same either way.

Bob · Jul 27, 2008

If you are going with 12 Volts, you may as well make it (-) ground.

This will save a LOT of confusion later with battery installation or charging, as well as jumnp-starting the tractor, or using it to jump-start something else.

Bus Driver · Jul 28, 2008

Most GM/Delco alternators before 1974 used an external regulator.

John T · Jul 28, 2008

A Generator will work fine at EITHER Pos or Neg ground but if you convert to an alternator Id go with Neg ground as most all except for special made require Neg ground.....If youre re doing it Id go with Neg ground n be done with it....

If you change Polarity the ammeter leads need swapped or else it would register bass ackwards. If wired right with the tractor setting not running if you turn on lights or ignition it should swing over to - discharge...

The coil is also polarity sensitive. With Neg ground its lil + terminal ought to receive ignition switched input voltage while its other lil - terminal wires to the distributor.....

Mske sure the VR matches your ground as some are labeled for Pos ground while others are for Neg ground.....

BE SURE TO POLARIZE THE GENERATOR BEFOREEEEEEEE YOU START HER UP...

John T

IH2444 · Jul 28, 2008

Remember those positive ground light bulbs are hard to find.

12 Volt Postive or Negative Grd. Which is best?

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