Why positive ground anyway?

[OldFarmall450]

Ok, almost everyone I come in contact with around here asks me why in the world does my 450 have a positive ground...and I keep saying I have no idea. Can someone enlighten me as to why this was done, and any advantages to it as opposed to the standard negative ground?
Thanks everyone.

ET

 

[Red Dave]

When that 450 was designed and built, negative ground was not the standard. Many older cars and trucks were positive ground. Some cars were positive ground into the early 1960's.

Electrically, it makes no difference at all. Positive ground for systems designed for positive ground and negative ground for systems designed for negative ground both work the same, just flow current a different direction.

 

[old]

Back in the day it was believed that + ground caused less problem of corrosion. Now if you have 12 volts system and an alternator it is likely t be a - ground since most alternators are - ground and hooking it up + ground will fry an alternator the moment you hook it up. A generator on the other hand does not care if it is + or - ground as long as it is polarized but some V.R.s do care which way they are hooked up

 

[rustybronco]

Electrons carry a negative charge. Current flows negative to positive.

Now you know why.

 

[Allan in NE]

Up until about '54-'55, just about everything was positive ground.

Allan

 

[gene bender]

Radio and Radar school at Ft.Monmouth NJ Army instructors RCA and PHILCO showed why with simple magnets ect why Pos was Pos ground it was used for many yrs cars ect till 12v came out even 6vpos gnd alts were used. Its involved theory

 

[John T]

I have read (NO Warranty, just what I read) that years ago before the industry started using NEG ground as standard, some believed there was less corrosion where frame members joined together if POS ground was used. In the tractor industry many older 6 volt tractors used POS ground but when they updated and changed to 12 volts (even still in Generator days long before NEG ground alternators were used) they standardized at NEG ground.

At Purdue University Engineering School in the sixties we were taught "conventional" circuit current flows POS to NEG, while "electron current" flows NEG to POS. That explains how INSIDE a battery the electrons, which are Negatively charged particles, have to flow NEG to POS so OUTSIDE the battery "conventional current" flows POS to NEG (it would be kind of hard for electron flow to suddenly change direction lol). Electrons are Negative charged particles so inside the battery where opposites attract and similar repel, the negative charged electrons repel away from the NEG and are attracted by the POS. Of course, this also all has to do with the physics and chemistry of a lead acid battery which is an electrochemical energy storage device.

Also there's the HOLE THEORY that says while electrons flow in one direction, what's left behind are the HOLES are flowing in the opposite direction. Electrons one way, holes left behind flow the other way.

Its been yearsssssssssssss since I learned all this and going on memory so NO FREAKING WARRANTY. I still view electrons as NEG charged particles which are repelled by NEG and attracted by the opposite POS, so inside a battery ELECTRON CURRENT is NEG to POS while OUTSIDE CONVENTIONAL CURRENT is POS to NEG. Likewise if electrons flow one way the holes flow the other

THATS MY STORY N IMA STICKIN TO IT FOR NOW AT LEAST LOL

John T Long retired AC Power Distribution engineer and NOT into electronics or Lead/Acid chemistry so maybe this is right maybe its wrong

 

[rustred]

i thought you were going to give a speach on ohms law , and e=mc squares and then count it out in binary and octal. ... so you must have forgot it all? this is a good post to explain all that with electrons jumping around and tiny bubbles getting attached to the liners and trying to keep them small and all that physics stuff i cant even try to explain. when i was in grade 10 i went to 2 phiysics classes, didnt understand it. so didnt go back. then when final exam came i went to write if for the fun of it. Old Sam the teacher passed me with 50 percent. lol. i even borowed 20.00 from him one time to go drinking when we used to skip wed. afternoon . he was a good guy.

 

[old]

Harassment like this is what I would expect form a grade school bullies not from a mature adult. What have I ever done to you to have you attack in such a childish way?

 

[Stuart]

If your a product of Navy training... that is scary

 

[rustred]

no harrassment intended. so dont have to get so jumpy. you were throwing around the big words talking about spark plug wires and Einstein and theory's.

 

[jimmyO]

I've been around for some of this stuff. For what it's worth...
In the late beginning, old Ben Franklin did some early work with electricity, kites, and keys. He knew something flowed, but of course couldn't yet know what went which way. So, as he explained it to me, he had to "just pick a direction", so figured he'd label the source of current as a +, as in "excess", and the destination a -, as in "I don't have enough electrons so I'll attract some". This flow was "electrical fluid"
Eventually, it was determined that electrons exist, and that they had a negative charge, and my friend Ben had simply picked the wrong direction. Realists, such as techicians, understand that electrons are the flowing thing, and flow from negative (lots of them) to positive (not so many). This is of course the reverse of old Ben's assumptions.
Engineers, on the other hand, out of respect for Ben and his original theory, and in continual denial of reality, continue to use "positive current flow" in all of their circuit analyses. If they changed, they'd have to switch all the plus and minus signs in their expensive text books to minus and plus. It also makes it difficult for realists such as me to go from my early technical world of electron flow to my later engineer's theoretical world of positive current flow. All the plus and minus signs get confused. And if you hook your tractor up with conventional (positive) current flow, the starter turns backward and the tractor will have 4 reverse gears and one forward gear, the bucket becomes a plow and the plow behind you removes furrows.
All of which has nothing to do with explaining corrosion if the electrons didn't know they were flowing the wrong way. And don't even think about semiconductors and hole flow, which is little more than putting chinese checkers into the mix, and unless you are using transistors, etc., is a whole different world. Which is why I like my old tractors better than new cars

My head hurts, so I'm going to do some gardening. Hope you got a chuckle from my explanation...
Jim

 

[Janicholson]

The starters on vintage tractors are series wound DC motors with a series winding the direction is not sensitive to polarity. Info, not a flame. Jim

 

[36F30]

Ever notice that tractors and vehicles with varnished cloth and rubber wiring insulation are positive ground and those with negative ground are insulated with the normal PVC insulation. It is related, but I aint got boots tall enough to step in this topic

 

[DanD]

FYI, Don't let a positve ground tractor touch a negetive ground tractor or vehicle while their running. It aint pretty.

 

[jimmyO]

Thanks for the reminder. I"ll have to talk to Ben F. about that.
Jim

 

[John T]

True, an electromagnetic generated field typical old tractor DC starter motor is NOT reversed by swapping polarity UNLIKE a permanent magnet motor which is. You can reverse polarity by swapping either the Field or Armature orientation with respect to the other.

John T

 

[John T]

I didn't get a chuckle but I did enjoy it !!!!!!!!!!! The way we were taught made it possible for the whole class to be on the same page and give the correct answers to test questions lol

John T

 

[John T PS]

PS I meant you can reverse DIRECTION by changing Armature or Field with respect to the other

John T

 

[tractorguy2]

Most tractors made in the 50's were positive ground. John
Deere,Allis Chalmers,IH,Ford. Case we t both ways. I ha e a 1948
Case SC. It uses a negative ground system. I can't find a negative
ground 6v regulator for it anywhere.

 

[rvirgil_KS]

Other than a scratch on the paint what will happen? As long as the hot sides of the battery don't touch there is no closed circuit for current to flow.

 

[David G]

I agree with John T, think it was for corrosion issues.

 

[Jon Hagen]

Think about this, Your using your NEG ground pickup to jump start a POS ground tractor. You connect a jumper cable from the pickup battery POS post to the tractor POS post. The POS post on the tractor is connected to the tractor frame. You let the pickup bumper touch an axle or frame on the tractor. You have just created a dead short across the pickup battery. 1000 amps in a dead short, red hot jumper cable, melted engine to chassis ground straps in the pickup, good chance of an electrical fire and maybe an exploded pickup battery. That's why you don't let a NEG ground machine touch a Pos ground machine while jump starting

 

[Janicholson]

Running makes no difference, (towed and pulled with a chain many many pos ground tractors with negative ground tow vehicles. Jump startting deserves isolation, not just running. Jim

 

[leon]

So, why negative ground anyway!

 

[OldFarmall450]

(quoted from post at 04:39:17 06/18/16) So, why negative ground anyway!

VERY INTERESTING info from one and all; so the next time someone asks me why its a positive ground system I can confidently look them in the eye, shrug my shoulders and say " Damned if I know!!" :lol:

I'll be sure and keep my tractor, Charlene, (that's her name, as in Full Metal Jacket) away from newer tractors. I see she's been casting sidelong glances at that big Ford tractor that bends in the middle parked close to her. I'll tell her he's no good for her and will only hurt her !!

But seriously, thanks for the abundance of info...some of it is waaaay to technical for me, but its all good info.

ET

 

[JDEM]

I guess we can all believe what we want. There is NO overall advantage to NEG or POS ground. Each system has its pros and cons. Just so happens that when semi-
conductors came into common use - a general "standard" was needed and NEG pretty much won. POS ground is still used for some things. According to the written history -
there used to be two competing schools of thought about how electricity flowed and so far - nobody on earth knows for sure. If the Hole Theory was believed in - systems
tended to be POS ground. If the Electron Theory was the theory of choice - NEG ground was used. The Hole Theory is rarely mentioned anymore, although it has never been
disproven or proven, just like the Electron Theory.

 

[tractorguy2]

What????

 

[OldFarmall450]

(quoted from post at 16:24:01 06/17/16) PS I meant you can reverse DIRECTION by changing Armature or Field with respect to the other

John T

John T, if I change the armature and reverse the direction will the tractor unplow the field, will the hay get unbaled, and the firewood unhauled ????

Sorry I just had to ask.

Regards,
ET

 

[Jaden]

At one time, there was a theory that the gas/air mixture ionized and burned better if current flowed from the hotter center spark plug electrode to the side. I don't think it was ever proved to be significant.