Farmall Cub Forum -- Questions and answers to all of your Cub related issues.
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After crank starting all summer, I finally got myself a battery . My cub is a 1950, positive ground, 6v system. I installed the battery and gave the starter a try. Success! The starter motor works fine and the cub fired right up. I then decided to see if the lights worked, so I flipped the switch to "D" and "B" and nothing . I then started wiggling the wires that go into the switch and suddenly the lights came on. Im going to have to pull the hood to check for a loose or coroded connection, but at least i have lights.
So finally, I decided to check if the cub was charging. Here is what I found: With the lights on, the ammeter reads about half way on the negative side. With the lights off and the battery disconnected the ammeter reads about negative 2. With the cub running and the switch on "H" the ammeter reads exactly zero. When i put my multimeter on the battery with the cub off it reads exactly 6.2 volts. If I put my multimeter on the battery with cub cub running and the switch in the "H" position, it reads 6.4 volts.
It seems that the generator is charging, but at a very low rate (.2 volts). I dont think that voltage would ever be enough to re-plenish the battery? Any suggestions what I should do next? I have not polarized the generator as of yet, but im not sure if that would help anyway since the current seems to be flowing correctly.
Regarding the lights, try cleaning the fuse contacts on the back of the light switch, they are bad to corrode and not amke a good contact.
as to charging, run a lead from the ground terminal of the battery to the F term of the gen. that eleiminates an problems with not getting a good ground on the lead.
you may want to try this chart.
Chart compliments of Farmall Bob
"The Constitution is not an instrument for the government
to restrain the people, it is an instrument for the people to restrain the
government lest it come to dominate our lives and interests." Patrick Henry
That means that your ammeter isn't centered. True zero is when it says -2. (Learn it and live with it.)
I think your trouble is all in your light switch. The fact that it charges at all indicates your cutout is working and your generator is probably working. The generator field must be grounded for it to charge. Since it is grounded through the same switch that only lights the lights after the wires are wiggled . . .
The amount that a generator produces is regulated by changing resistance between the field terminal and groud. Zero resistance is maximum output. If your switch has a poor internal connection for the field wire, or is itself poorly grounded, output decreases. I bet if you took your switch apart (often a one-way street), you would find the concacts badly corroded.
FYI.........after painting and reassembling our tractor .......no lights.......no ground between lights and hood
owning a cub makes heroin addiction seem like a vague wish for something salty
5 posts • Page 1 of 1
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