Antique Automotive Electrical Question on Battery Polarity
Antique Automotive Electrical Question on Battery Polarity
(OP)
I write articles and field questions for several Vintage automotive publications. A question has come up several times that I can not find the answer to. From the 30's into the 50's cars used either a positive or a negative grounding system. Some manufacturers used both. For instance all GM cars used negative ground, except for Cadillac and La Salle that used a positive battery ground. Ford, Chrysler, and most of the smaller companies used a positive ground. In the 50's with the switch to 12 volts, grounding was standerdized to negative. Except for Packard, the British, and some cars made in Europe. I feel that there must have been a solid engineering explination for the use of differant polarity, but I am unable to find any information on this. All I can find is a bunch of "Old Wives Tales" about corrosion, and current flow that don't hold up. I hope someone can help. Thank you! BDagle





RE: Antique Automotive Electrical Question on Battery Polarity
It used an alternator that was cleverly designed so that it could be assembled for positive or negative ground.
This, I know.
Why, I don't know.
Oral tradition is a lossy communications medium.
As a result, the context within which old wives tales are true, is not always preserved.
The tales are, mostly, true.
Mike Halloran
Pembroke Pines, FL, USA
RE: Antique Automotive Electrical Question on Battery Polarity
I really liked one post about bridges using a DC current system to prevent corrosion, and if the car was negative ground all of the connections would eventually fail like the bridge. Scary...
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Antique Automotive Electrical Question on Battery Polarity
RE: Antique Automotive Electrical Question on Battery Polarity
I think everybody finally changed to neg earth when radios became popular, as DIN sized radios only seemed to come in neg earth.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Antique Automotive Electrical Question on Battery Polarity
Could just be boll#cks though.
Bill
RE: Antique Automotive Electrical Question on Battery Polarity
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Antique Automotive Electrical Question on Battery Polarity
I winder whether it actually works.
Fe
RE: Antique Automotive Electrical Question on Battery Polarity
reference bridges... I would presume bridges or any other structure with underwater steel could make use of similar procedures to control underwater corrosion.
RE: Antique Automotive Electrical Question on Battery Polarity
RE: Antique Automotive Electrical Question on Battery Polarity
But since that big + sign looks better they wanted it to be the hot, no one likes negativity. LOL
RE: Antique Automotive Electrical Question on Battery Polarity
If the central station of the original telegraph systems was positive then would the ground electrode corrosion be mostly at the remote station electrodes. A ground return would make the remote stations negative.
Whether this had anything to do with the choices for automobiles, it could be the source of the "Positive ground to prevent automobile corrosion" legend.
Bill
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