Why POS ground ?.

Alright guys i have always wonderd why would any tractor manufacturers like JD woukd have the electrical system 12 volt POS GROUND ? WHAT was their purpose ? Doesnt make any sense to me. SOOOOO, what am i missing ? Do they start easier ? Start faster ? Why didnt they make the system Neg ground ? Thanks.

Let me put away my can of worms....

Earlier than that they were 6V pos ground. Don't know why.

In the early days of electricity, it was thought that electrons flowed from the negative pole to the positive pole. Later they figured out that electrons flow from positive to negative. Maybe.

That WHAT im talking about !!!! 6 volt POS ground !! Why the heck the POS ground ?? Maybe they were to lazy to switch wires around ?

I read somewhere early manufacturers (Ford & Chrysler I think) believed there was less galvanic corrosion where auto frame members met if the chassis was used as the positive connection. Later things got standardized at Neg ground.

John T

And these days they again claim the electrons do indeed flow
from neg to pos. After all, they are negatively charged
entities....

Physicist and engineers agree I believe (at least how I was taught in the sixties) electrons are NEGATIVE charged particles flowing from NEG to POS while the empty spaces or so called "holes" left behind flow from POS to NEG. But Ive slept since all those courses so no warranty lol

John T

Positive and negative ground is like right hand and left hand threads on a bolt. With bolts the nuts screw on in opposite directions, with positive and negative ground current flows through the circuit in opposite directions.

Some electrical devices are polarity sensitive, meaning that current flows through them in a certain direction such as ignition coils, ammeters, charging systems, and some gauges.

Most polarity sensitive devices can work with either ground configuration provided they are properly connected in the circuit.

Old tractor/vehicle circuits can work with either polarity. It was designer’s choice, and politics, competition, and corrosion theory were probably all a factor in the decision which to use.

Positive ground does not seem right to us since American manufacturers adopted negative ground as the standard beginning about 1956.

They have to be either negative or positive chassis return with DC mobile machinery . They are the only two choices so pick one.
Although the 24V components of JD tractors from about 1958 to 1968 did not use the chassis as a current path.
Some parts of the world drive on the left side of the road too.
The NPN resistor was why chassis return systems went to negative .

I read once they thought back in the day positive ground would corrode less.

Probably for the same reason they used to switch the negitave leg in a house.

I was going to give you a prize until you took it backwards...

We can thank our very own Benjamin Franklin for getting it backwards to start with thus the name positive ( for an excess of ) to mean the electrical fluid was supposed to leave this post and travel to the negative post of batteries. He had a senior moment and got it backwards, and it's not a fluid even though it behaves exactly as such mathematically, it is in fact electrons which are negatively charged particles that travel along the outside electron orbits of conductive molecules. They couldn't confirm the flow direction concerning batteries until several decades later and then even more decades for agreed acceptance among those in that field. Meanwhile...

Ground being the best terminal and engineers wanting control, they made the ground positive at first because the word really hadn't got out to that education level that ol Ben had it backwards to start with. I suspect galvanic corrosion excuses were made up at that time to just shut people up - I've never seen any such corrosion in the first place especially since the negative ground cars should be just overrun with it by now.

So with a better higher education system comes the realization that the basics are in fact backwards and one fine day they decide to not do it that way anymore. Soon after they double the cell count for more volts so as to overcome hard starting in the winter and here we are.

For years I blamed Voltaire for the foul up, and was most surprised to learn it was in fact the guy flying kites while lightening was about that was the guilty party.

John T gave you the right answer

Thanks John T !!!!

(quoted from post at 22:22:01 09/13/14) Probably for the same reason they used to switch the negitave leg in a house.

Click to expand...

What ? Serious or joking ?

Why negative ground? Why do they call it "positive" and "Negative" why not "left" and "right" or "to" and "From" or even "John" and "Marsha"? Some EE had the idea to do it with a positive ground, others had the notion to do it the other way, eventually one idea became the norm.

Which way does current flow,
I have a large electrolysis tank for removing rust and paint, etc.
Negative connects to part and positive connects to sarificial electrodes. Rust etc, transfers to positive electrodes. When galvanizing or chroming the connections are reversed
This supports what some of the posters claim...
current flows from negative to positive. Just the opposite of what most think.
This brings up another point... If rust etc. flow to the sacrificial (pos.) electrodes why are they the ones destroyed?