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Negative battery ground.

D

Denny McSweeney

New User
I just bought a Farmall "H" and it has a negative battery ground. I have been told, and it is in the manual that the Positive should be ground. What damage will it do, and should I reverse the ground. If I reverse, what procedures should I take???

Denny
 
Does the charging system work? The tractor doesn't really
care either way as long as the wires to the coil have been
flopped. If it is charging and running fine leave it that way.
Some folks do it so that everything they have is the same - it
keeps them from hooking up something hing wrong. An
alternator needs a negative ground. If it has been switched to
an alternator don't bother it.
 

I don't know about wires being flopped???

It has a magneto.

I am about to get a new battery so how do I know if it is charging?

Denny
 
Only correct way to know if it is charging is to put a meter across the battery both when not running to get battery volts then with it running. Not running you should have 6.3 or so volts and running you should have 7-8 volts if the charging system is working. That all said you can run a tractor like you have for years with out a working charging system as long as you keep the battery charged. Had one that I ran that way for years till I got around to fixing it
 
Being the battery posts are different sizes(positive
is bigger) it will only hook up one way. Look at the
ampmeter. if it shows chg,it works.If it doesnt,it
probably doesnt.Check with a volt meter.
 
By the way do not ever try the pull the battery cable off trick to test if the charging system is working. That is a good way to get hurt or dead plus fry the system and in your case it would not work since you have a mag
 
Since you have a 6 volt system I would say that it
should be positive ground. There are very few
vehicles out there with a 6 volt negative ground
system. If the battery was just used for starting
it won't matter. The starter will turn the same
direction no matter what way the battery is
connected. As for the amp meter it will most
likely read discharge since current will be
reversed. I believe there are voltage regulators
have to be rated for neg or pos ground systems.
It's been a long time since I fooled with one.
 
Fact of the matter is it will run just fine either way. There are no polarity-sensitive electronics on these old tractors.

All you have to do to switch polarity is:

1. Swap ammeter cables so it reads the right way. Disconnect the battery first.
2. Swap battery cables.
3. Polarize the generator.
 
if it is charging ( check with meter as per old's advice ). and it is magneto, then I'd leave it hooked as is. IE. your bat posts and cables are setup already. put it back that way..
 
When it comes to electricity, Never guess. My IH
C is 12v negative ground. My Jubilee is the same.
So they may have been positive ground on 6 v. So
if yours has a 12v system it very likely the
ground has been changed to negative. I've never
seen a 12v positive ground alternator. So if you
have 12v and an alternator, my money is on
negative ground.

I'm also going to speculate you have a mag like
my 1950 IHC, so looking to see how the coiled is
wired won't work.

Another thing to look for. The positive terminal
on a battery is bigger than the negative. So look
at the wire tied to ground. If it's the smaller
terminal, then negative ground.
 
In 1963 we had a customer that had an Oliver 1800 that he used to haul tomatoes with on two wagon with lights on them just like a semi-trailer. The generator would not keep up. We ordered him a positive ground alternator since the tractor was positive ground from the factor. It worked good.
 
I learned something. I've never seen a + ground alternator.

When did the old tractor convert over to - ground?
 
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