MTFCA Forum

Thanks Mike

Originally negative ground.

Nice looking Runabout too !

Positively... Negative ground.

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A while back I did some research and found the following:
Why a Positive ground?

For early cars with varnished cloth wires would absorb moisture and cause corrosion. It was found that reversing the polarity would actually reduce corrosion.

Why a Negative ground?

After plastic coating of wires was common and the transistor was desired. Electronics industry standardized NPN (Negative-Positive-Negative) transistors.

So Ford Ts were based on the original thought that electrons flow from positive to negative and we should turn off the positive. In reality the electrons flow from negative to positive an evidently that can cause a issue to leave the charge across the ground creating corrosion so Model A went to positive ground. Does anyone know when for switched back?

Enjoy,
Matt

Thanks

Ford returned to using the negative ground system in 1956 and also 12 volt batteries

Unless you are running a diode or modern voltage regulator, the T does not care what ground you are using as long as the meter is hooked up right. The old books said to reverse the leads every so often on non generator cars to even the points wear if running them on battery. Mechanical cutouts don't care what ground is used as long the generator is polarized to that ground.

Michael

that is a very nice looking car