M grounding

[IA1456]

Wondering if anybody could tell if a 52 M was a positive or negative ground or how does one tell if it is hooked up correctly. Got a friend got one given to him so I know nothing about it

 

[Bob M]

6 volt, positive ground from the factory.

But 70 years - and likely multiple owners - later, who knows...

 

[IA1456]

Ok thanks. Thats what I thought

 

[Janicholson]

If it is 6v it is likely pos ground (factory) if 12v generator it could be either, as the generator can be polarized for either. If 12v alternator (aluminum not painted iron for a charging device) it is likely negative ground. The terminals are different sizes. They do not fit easily on the wrong posts. If the battery is in it the battery will have marks indicating the polarity near the posts. Jim

 

[BarnyardEngineering]

First, most obvious way to tell: Which post of the battery is connected to the frame of the tractor?

If it still has its original electrical system, though, ground really does not matter. There are no solid state polarity sensitive components on a stock Farmall M. Yes, the ammeter will read backwards but it won't emit a puff of smoke if you hook it up wrong.

Hook it up positive ground if you want it original. Hook it up negative ground if you want to screw with the next guy's mind. Polarize the generator either way, and you're done.

 

[n9lhm]

Whatever polarity you wind up with, if it has battery ignition instead of a magneto, making sure the ignition coil is connected with the proper polarity will ensure the best ignition system performance.

 

[redforlife]

Originally 6 volt positive ground from factory. It's anybodys guess as to what it is now. It'll no doubt take some investigating to know what you got. Gotta know what you got, to know which way to hook a battery up.
Partial electrical conversions are common to see on these in modern times. That could mean anything from converted to negative ground, to a full blown 12 volt, negative ground, with alternator conversion, or anything in between.
Be careful. If it has a voltage regulator, they are easy to fry (don't take much) and are expensive to replace.
How current battery is hooked up, may tell you. But, its also possible that someone before you hooked it up wrong. But, if so, it probably already fried what it'll fry, and you won't fry anything more if you hook another battery up the same way. If its not right, you'll have to investigate to figure out what you got, which way its suppose to be according to what you got, and fix what is fried. So, basically thats where your at.

 

[Rich'sToys]

If it has a distributor, then whichever wire on the coil goes to the distributor is the same as what the ground is. i.e. if the + terminal on the coil goes to the distributor, then the system is positive ground, and vice versa.

 

[Brownie450]

If you have a digital Volt meter & suspect
the tractor is negative ground, put the black
--negative probe on a good ground & the red--
positive lead on the cable from the battery
to the starter hot terminal.
If the reading has a minus in front of it,
it is positive ground. If the reading doesn't
have a minus in front of it, it is negative
ground.
Jim

 

[cuby]

Large post on battery is positive. Trace that cable to where it goes. Factory is 6 volt positive ground. Some change over to 12 volt & keep the positive ground when using a 12 volt gen {Have seen that}. Alternators are usually neg. grd., but not all are.