Positive or Negative ground

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marshall
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Tractors Owned: 1950 Farmall Cub

Positive or Negative ground

Postby marshall » Wed May 18, 2022 6:28 pm

I took my cables off to charge the battery and didn't make a mental note about the cables and terminals.

1950 Cub with 12-volt system with generator and 6-volt starter. Is it a positive ground?

tst
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Re: Positive or Negative ground

Postby tst » Wed May 18, 2022 6:39 pm

1950 was a 6 volt positive ground cub , someone converted it to 12 volt ? or did someone just jam a 12 volt battery in it ?? if converted they could have done it either way

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Glen
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Re: Positive or Negative ground

Postby Glen » Wed May 18, 2022 7:14 pm

Hi,
The battery posts are different sizes on 6 volt or 12 volt batteries, the positive post is bigger on either voltage of battery.

Look closely and see which battery cable end is opened bigger. You can try putting the battery in both directions, and see how the cable ends fit on the posts.
The positive cable end should fit too loose on the negative battery post, and the negative cable end should be too small to go on the positive battery post.

If it still has the original 6 volt generator, that shouldn't be run on 12 volts. :)

Jim Becker
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Re: Positive or Negative ground

Postby Jim Becker » Wed May 18, 2022 7:51 pm

If it is a cut-out system with a magneto, a 12-volt battery can be used with relatively little trouble. A 1950 Cub could be either a cut-out system or a regulator system.

marshall
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Tractors Owned: 1950 Farmall Cub

Re: Positive or Negative ground

Postby marshall » Wed May 18, 2022 9:42 pm

Glen wrote:Hi,
The battery posts are different sizes on 6 volt or 12 volt batteries, the positive post is bigger on either voltage of battery.

Look closely and see which battery cable end is opened bigger. You can try putting the battery in both directions, and see how the cable ends fit on the
:)


That's what I was noticing as I was trying to hook it back up. One of the cable ends is definitely too small for a terminal on the battery so I guess it goes on the other where it fits. Positive ground. I better paint a "+" near where the cable bolts onto the chassis so I don't forget this again.

Thanks for the clue.

Jim Becker
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Re: Positive or Negative ground

Postby Jim Becker » Wed May 18, 2022 9:48 pm

Red is the conventional color for positive connections. Is there any red paint near where the ground cable is bolted? :)

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Glen
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Re: Positive or Negative ground

Postby Glen » Thu May 19, 2022 6:50 pm

Hi,
IH changed the Cub electrical system some during 1950, at Cub serial number 115403. You didn't say what the serial number of your Cub is.
Below is info for both systems, you can look and see if the generator is the original 6 volt gen.

Below is a page from the 1950 Cub owner's manual showing the original 6 volt generator and other parts, used up to serial number 115403.

The original Delco gen for those was probably model number 1101355, and has a cutout, or Relay, IH called it, on top of it.
There is originally a plate on the gen with the model number.
There is also originally the 4 position charge rate and light switch on the dash.

http://farmallcub.com/rudi_cub/www.clea ... e%2033.jpg

The original Delco gen for the newer system, after serial number 115403, was probably model number 1100501, and has a voltage regulator, mounted on a plate beside the gen.
They changed to a 3 position light switch, which is for just the lights.
They used the 3 position light switch until mid 1958.
The Battery Ignition unit became available at serial number 115403 also.
Below is a page from the 1955 Cub operator's manual, showing the system. :)

http://farmallcub.com/rudi_cub/www.clea ... e%2050.jpg


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