positive to negative ground
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Topic author - Posts: 41
- Joined: Tue Jan 22, 2019 8:10 pm
- First Name: Martin
- Last Name: Cobb
- * REQUIRED* Type and Year of Model Ts owned: 1917 engine, 1916 Runabout, 1915 engine & chassis
- Location: Northbrook Illinois
positive to negative ground
My Model T (1916 with a 1921 starter engine) came to me wired with positive ground. I would like to change it to negative ground (just because that's the way Ford did it).
Advice please: Can I simply polarize the generator by putting B+ to the field, reverse the battery cables, and go? Will the cutout work with no change? Should I replace the cutout with a regulator?
Martin
Advice please: Can I simply polarize the generator by putting B+ to the field, reverse the battery cables, and go? Will the cutout work with no change? Should I replace the cutout with a regulator?
Martin
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- First Name: john
- Last Name: karvaly
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Re: positive to negative ground
You are correct. A mechanical cutout doesent care.
If you have a diode/electronic or Fun projects type cut out it matters. Be sure of your cutout type.
If you have a diode/electronic or Fun projects type cut out it matters. Be sure of your cutout type.
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- First Name: John
- Last Name: Kuehn
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Re: positive to negative ground
So do you still have to do anything to the generator by polarizing it or etc? If it has the std. mechanical cutout it doesn’t make any difference.
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Re: positive to negative ground
Polarize The generator only. One quick spark per the manual.John kuehn wrote: ↑Mon May 12, 2025 1:57 pmSo do you still have to do anything to the generator by polarizing it or etc? If it has the std. mechanical cutout it doesn’t make any difference.
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Topic author - Posts: 41
- Joined: Tue Jan 22, 2019 8:10 pm
- First Name: Martin
- Last Name: Cobb
- * REQUIRED* Type and Year of Model Ts owned: 1917 engine, 1916 Runabout, 1915 engine & chassis
- Location: Northbrook Illinois
Re: positive to negative ground
Thanks to all who responded!
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Re: positive to negative ground
Martin, with positive ground the starter works fine?
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Topic author - Posts: 41
- Joined: Tue Jan 22, 2019 8:10 pm
- First Name: Martin
- Last Name: Cobb
- * REQUIRED* Type and Year of Model Ts owned: 1917 engine, 1916 Runabout, 1915 engine & chassis
- Location: Northbrook Illinois
Re: positive to negative ground
The starter will be fine. I've used 12 volts negative ground systems with several old six volt positive ground starters. But now that I think about it I'll need to reverse the wires on my ammeter.
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- First Name: Robert
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Re: positive to negative ground
Changing over to negative ground and polarizing your generator, does your ammeter show a positive charge when running without headlights on. ??
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Re: positive to negative ground
First of all, turn the battery cable connections around. You will also need to reverse the leads on the ammeter. I think the generator would need to be re-polarized. As far as I know, the starter doesn't need any attention.
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- Posts: 1863
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Re: positive to negative ground
Pat .... It would be physically better to remove the battery and then reinstall with the negative terminal closest to the frame rail, reconnect cables to battery, install battery, hold downs and enjoy your ride.
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- First Name: James
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Re: positive to negative ground
I am kind of new with Model Ts, I didn't get one until 1978.
One question that has never been answered was, "why was the ground changed from negative to positive?"
One question that has never been answered was, "why was the ground changed from negative to positive?"
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- Posts: 1863
- Joined: Sun Jan 06, 2019 8:20 pm
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Re: positive to negative ground
James ... Martin started this thread referring to the car he purchased that had the battery positive grounded, a problem that comes up with the belief that Model T's were the same as Model A 's.
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- First Name: Norman
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Re: positive to negative ground
See my comments on your other post with this name
Norm
Norm
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- Posts: 1863
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- Board Member Since: 1999
Re: positive to negative ground
Norman and all, you can check my response on the other post topic of positive and negative grounded electrical.