grounding positive or negative

I was looking at some old wiring diagrams for an Overland car in the teens-early 20s, and they were 6v negative ground. *actually the caption at the bottom said "the battery negative is grounded to the starter motor." hope i understood that correctly. The generator manufaturer was Autolite.

If those cars (#2 behind ford early on) truly were neg. ground, I wonder how much influence Delco-Remy or FoMoCo (how were the Ts grounded?) had on industry conventions? or maybe there never was a standard and agricultural products got Delco to save engineering and sourcing costs, so coming from tractors we are merely Delco-blinded?

I've got a Dyke's auto encyclopedia from '29 that may have more clues in it, but there's more to read in there than the Bible!

karl f

My '48 Super A is grounded to the starter, what I mean is, the positive cable runs from the 6V battery to the mounting bolt of the starter.
The negative cable runs from the battery to the starting switch on the starter.
Vern

There was no industray standard. However, MOST manufacturers used positive ground for six volt systems and negative ground for twelve volt systems. There were exceptions in both automobiles and tractors.

Harold H

Millions of 6 volt Chevrolets are negative ground.

I read somewhere that before there was any industry standard FORD & CHRYSLER (remember the early autos were mostly 6 volt) used Pos ground cuz they believed it woull lessen galvanic corrosion where frame members joined while GM didnt jump on that same bandwagon early on I dont believe.

Much of the tractor industry used Pos ground on the early 6 volt units but as time passed and 12 volt came more popular they, like the auto industry standard, also went to Neg ground....

John T

Tom, I think youre right, see my post above, It was Ford n Chrysler that used Pos ground if I recall correctly

John T

Military and civilian electronic schools teach opposite theories on DC Current Flow. One teaches DC Current flows from positive to negative and the other teaches the current flows from negative to positive.
Actually it doesn't flow at all it is just the difference in potential.
BUT, the question, is the spark in your spark plug jumping form negative to positive or positive to negative is a good question. I guess the better question would be is it jumping from gnd to pos or from gnd to negative or from pos to gnd or from neg to gnd.

Enjoy,
Dell

allright, after some reading, this is in 1929 mind you:
"Most manufacturers ground the negative (-) terminal of the battery and generator. The Westinghouse Co. grounds the positive (+) terminal in a number of its systems." (Dykes Automobile and Gasoline Engine Encyclopedia 15th edidtion p. 412)

page after page of wiring diagrams and just as many positive ground as negative ground cars back then. The model T ford is covered in its own chapter and shows negative ground (no model A in a 29 book?...i bet it took 2 years to catch up with print materials back then). There were some voltage regulator equiped cars, but many still had to be regulated manually.

I love this technical history stuff.

The correct way of teaching which way the current flows will probably never be settled. Someone on yt, likely John T, said it's *only* the Theory of Electricity. Every few years new discoveries at the atomic level are made, helping us understand a little bit more, or making us blush in embarassment for believing a certain factoid for 50 years.

bottom line when it comes to correctly grounding your tractor is, check the charging/regulation system before battery is connected. if you have an alternator, it's probably negative (some exceptions). If you have a generator, check the back of the regulator if equipped for ground indication. that should help let less smoke out of the components. I'm not sure how pos ground or alternate voltage alternators are identified, and if polarity matters on a cut-out manual regulation system.


karl f

Good info Dell, for the record its easier to emit an electron (a negativley charged particle) from a hotter surface (spark plugs electrode tip) to a relatively cooler (plugs ground strap) surface. Thats what all the Pos or Neg ground versus how the coil's wired (its polarity) has to do with. Its the same reason in a vacuum tube a heater is under the cathode to emit electrons up to the cooler plate

John T Electricity NERD lol

Karl FUN discussion, FWIW heres how I recall we were taught at Purdue but remember thats been over 40 yeas ago so cut me a lil slack now.....Maybe Jimbo or Bob or Bob M or jdemaris or some smarter electrical gents can bail me out here??????????????

Good conductors like copper have plenty of spare free electrons circling around in the outer atomic orbit. An electron is a negatively charged particle and it flows away from a lower Neg state to a higher Pos state (opposites attract, likes repel) i.e. from Negative to Positive CALL IT ELECTRON CURRENT

HOWEVER the holes/vacancies left behind when those electrons got knocked out of their orbits are flowing Positive to Negative CALL IT CONVENTIONAL CURRENT

Something like that, its just been toooooooo long ago and I may have slept that day lol

Olddddddd John T long retired EE

Good Morning John,
So, does lightening jump from earth to the source or from the source to the earth.
Better yet, does the static discharge that wakes me up with a bang every morning jump from my finger to the fridge door or from the fridge door to my finger
Dell

Geeeeeee Dell, I dont know everything lol

I think lightning is actually opposite from what people think n how it looks, seems like its from earth up?? BUT AGAIN elecrons flow one way while the holes/voids/vacancies flow the opposite

On static elecricity, I see it as a build up of excess electrons sooooooooo they (- charged particles) flow off/away/from the source (like the big ball on a VanDeGraff Genertor) to a surface with less charge ?? When you scuff across the carpet electrons build up on your body which rush to a lower charege state (the kitchen sink) when your finger nears it,,,,,,electrons flow to sink, holes/voids flow to you

BUTTTTTT isnt electricity similar to a VanDeGraff Generator i.e. those clouds from friction and flowing through air build up an excess accumulation of electrons (- charged particles) so once the potential voltage difference from them to earth is high enough you get a current arc through the air resulting in electrons rushing to a lower charged earth while holes/voids rush opposite to cloud???????

DARN IF I KNOW as this shows

John T Runnin outa smarts here and it dont take all that much to get there lol

Dell,
I'm bettin' it was electrons that jumped from your finger to the 'frig door (or the other way around). Holes are just vacant spaces on an atom where an electron should be to keep it from being a charged particle. I doubt that it was part of the 'frig metal or your finger's flesh that took the trip across the gap and gave you a jolt. (Grin)

I have an Essex 1927, and just happen to have the 2" thick repair manual at my elbow. The starter and distributor are Autolite and the 6 volt battery is Negative Ground to the frame.

(quoted from post at 06:15:37 03/15/09) Military and civilian electronic schools teach opposite theories on DC Current Flow. One teaches DC Current flows from positive to negative and the other teaches the current flows from negative to positive.

Enjoy,
Dell

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Actually I don't think that's true. I've read plenty of "civilian" books and went through Navy Electronics "A" school in the late 60's. All "taught" electron flow

I have an old radio book printed in the mid 20's which talks about both electron flow and some unexplained mysterious "current" flow from pos to neg.

(quoted from post at 08:30:30 03/15/09) Good info Dell, for the record its easier to emit an electron (a negativley charged particle) from a hotter surface (spark plugs electrode tip) to a relatively cooler (plugs ground strap) surface. Thats what all the Pos or Neg ground versus how the coil's wired (its polarity) has to do with. Its the same reason in a vacuum tube a heater is under the cathode to emit electrons up to the cooler plate

John T Electricity NERD lol

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Pos or neg battery ground has nothing to do with the spark. THAT is determined solely by how the coil is wound/ wired/ connected, or maybe I misinterperted what you were trying to say


So far as alternators, you "could" change some alternators to positive ground---such as the older GM/FORD/Mopar ones with the old individual diodes, by removing all six diodes, and swapping the two sets of three around.

So far as generators, you can run a generator either way. what DETERMINES "ground" is the way it's "flashed" (which you can change) and the construction of the contacts in the regulator. SOME aftermarket/ replacement regulators had heavier contacts and could be used either way. I used to sell auto / truck parts, and remember that some part numbers in Standard Motor Products (Blue Streak) showed this

There WERE some fairly modern trucks made in 12V pos. ground. Don't ask me for the brands, I think some were firetrucks. I've been around Motorola two-way, and at least some of their radios could be configured and or ordered for pos ground 12V use, and "we" had to order at least one 12V to 12V inverter for one customer--to run some neg. ground gear in a 12V, pos ground truck.

(Personally, I'd 'ha changed the truck ground!!)

I'm of the age to remember 6V cars, Ford didn't "come over" until 56, VW until later, what, 63? Personally, I think "we" should all have 24V cars, but now that the hybrid fever has ??hit?? that may be moot. I'm glad I'm getting old. As an amateur radio op, the new cars are crap for radio noise/ interferance, and my understanding is that the hybrid breed is pretty bad. Not only that, but the "standard" of 12V accessories may be gone in a few years