positive or negative ground

Hi Guys and Gals:

How do you tell if my 1949 8N is positive or negative ground? I really don't understand the concept..Thanks and you all stay safe

The concept isn't that difficult if you look at it as a trip to the beach.

When you leave home, you drive west to get to the beach.

When you leave the beach, you drive east to get home.

It's a circuit. The electrons can leave the battery from the positive side or the negative side.

Same result.

Look at the POSITIVE post on your battery. It's larger than the negative post and has a " + " sign or POS beside it. If the cable attached to the post is also attached to the frame of the tractor, it's positive ground.
75 Tips

(quoted from post at 07:07:59 05/17/20) Hi Guys and Gals:

How do you tell if my 1949 8N is positive or negative ground? I really don't understand the concept..Thanks and you all stay safe

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To tell you look to see which terminal on the battery is connected to the chassis. If the positive battery terminal is connected to the chassis the wiring is positive ground. If the negative terminal is connected to the chassis the wiring is negative ground.

The concept is simple. The metal frame of the tractor is used as a common electrical conductor for the various circuits in the electrical system - e.g lights, ignition, starting. That common conductor is called "the chassis ground". Individual wires connect one terminal of the battery to things like the lights and the chassis is used for the return connection. This cuts the number of wires needed in half. Functionally it makes no difference which way the battery is connected as long as all of the individual electrical components are arranged to match. Things like lights and generators work either way. But transistors in devices like alternators do care and if you hook them up backwards you will damage them.

TOH

thanks everyone.. Hope you all are safe and well during this madness

Not to hijack the thread - but - if the battery is not on the tractor then how do you know which way to connect it?
If genny - then it doesn't matter?? but if Alt then it does??
I've an 8N 6v +ve grnd and each spring I have to stop and think twice before I install the battery after its winter storage.

And, bonus history question, is there a reason why over the years vehicles have changed from +ve to -ve ground?

(quoted from post at 05:31:49 05/17/20) The concept isn't that difficult if you look at it as a trip to the beach.

When you leave home, you drive west to get to the beach.

When you leave the beach, you drive east to get home.

It's a circuit. The electrons can leave the battery from the positive side or the negative side.

Same result.

Look at the POSITIVE post on your battery. It's larger than the negative post and has a " + " sign or POS beside it. If the cable attached to the post is also attached to the frame of the tractor, it's positive ground.
75 Tips

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Bruce, if you drive west to get to the beach, you are going to have one heck of a long drive!! :lol:

(quoted from post at 10:27:01 05/17/20) Not to hijack the thread - but - if the battery is not on the tractor then how do you know which way to connect it?
If genny - then it doesn't matter?? but if Alt then it does??
I've an 8N 6v +ve grnd and each spring I have to stop and think twice before I install the battery after its winter storage.

And, bonus history question, is there a reason why over the years vehicles have changed from +ve to -ve ground?

Click to expand...

Generators work either way BUT if you reverse the battery polarity they need to be (re)polarized in order to make them charge. That's a 60 second job with a small jumper.

Hook an alternator up in reverse polarity and you will almost surely fry it.

Industry needed/wanted a standard and they settled on negative ground "just because". I am sure there are some nuances to that "just because" but either could have been chosen. Sort of like VHS vs, BETA.....

TOH

In the early days of D.C. electricity, the theory was and still is that electrons flowed from negative to positive. Telephone central offices were and still are positive ground. Ford went along with that for years until, like TOH said, they went along with an industry standard.

(quoted from post at 12:48:29 05/17/20) In the early days of D.C. electricity, the theory was and still is that electrons flowed from negative to positive. Telephone central offices were and still are positive ground. Ford went along with that for years until, like TOH said, they went along with an industry standard.

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I think in the early days the theory enunciated by the guy with the kite was just the opposite and despite physics to the contrary that convention continues today.

Conventional vs Electron Flow Models

TOH

Enjoy!
Here are a couple of takes: ( not ALL factual, just part)

1) Model T Ford had it right with Negative ground, then Ford "fixed" it with the Model A (Pos gnd), then Ford "fixed" it again in 1956 (back to Neg Gnd).

2) Ford was almost ready to go into production with the Model A & discovered that spark was positive...investigation revealed that the coil was manufactured wrong! Henry, being the frugal man that he was, said," take too much time & money to scrap/re-manufacturer all those coils...just reverse the battery cables". Finally fixed that mistake in 1956.

3) Had it wrong with Model T, fixed it with Model A, then made it wrong again in 1956.

4) Had it right with the Model T, messed it up with the Model A, couldn't admit mistake until all the guilty players were dead & then fixed it in 1956.

5) When lightening strikes, it is an electrical discharge from a Negative cloud to a Positive Earth, so if it was good enough for God, then it was good enough for machines. Of course the main current is in the return discharge from Earth to cloudbut the Earth is still the Positive end of it.

And FINALLY,

5) It doesn't make any difference, like left/right hand threads on lug nuts, as long as user knows how it is set up, either work just fine. It is just a convention necessary to facilitate communication. :idea:

Good evening Angus: The posts on the battery are not the same diameter, assuming you have the original type 6 volt battery. The clamps at the ends of each cable will fit on the same posts the previous owner put them on, right or wrong! Not saying the previous owner was correct, but it does put you in same configuration where you started. Maybe some help.

Dennis M. in W. Tenn.

went to buy an int 300. the guy started it right up and it looked okay. bat wasn't hooked up when I got there. neg post wasn't connected. 12 volt bat was less than a year old. hooked it up and started fine. gave him a check. went back the next day and it wouldn't turn over. bat was still hooked up. cousin brought his booster and it fired right up. apparently he hooked the battery to positive ground and it ran the battery down. swapped leads. charged battery and never gave me any problems. it has an alternator on it. so it apparently will work either way but flow of electricity will only stop if wired correctly. the plus on the battery post should go to the starter for positive ground. anyway that's my story. plus sign on bat is positive. minus sign is negative. red wire is positive, black wire is neg. stay safe people.

(quoted from post at 07:07:59 05/17/20) Hi Guys and Gals:

How do you tell if my 1949 8N is positive or negative ground? I really don't understand the concept..Thanks and you all stay safe

Click to expand...

Generators work either way BUT if you reverse the battery polarity they need to be (re)polarized in order to make them charge. That's a 60 second job with a small jumper.

Hook an alternator up in reverse polarity and you will almost surely fry it.
TOH

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As said, can be run either way. Take note of TOH comment about ALTERNATORS.

Only other thing to add is if you have a side mount coil, which has both a POSITIVE and NEGATIVE primary terminal, observe the battery polarity here too, ie: battery POSITIVE GROUND - coil primary POSITIVE to points. Battery NEGATIVE GROUND - coil primary NEGATIVE to points. Will actually work either way, but let's keep polarity's correct. Theoretically works better when polarity is correct.

Oh yea, Polarizing.... about a 2 second job.

Thanks for all the answers - especially the history, that's always interesting & educational.