Farmall A charging?

Young Mechanic · Feb 16, 2019

Back on this A again, got it to oil the rockers finally. Now I'm on the charging system, this tractor has a mag, and a cut out rather than regulator. So put on new wiring harness, it had two yellow wires hooked one from gauge to bat terminal on cut out, hooked the other from post on light switch to field post on generator. Started tractor didn't charge, turned on lights no charge, grounded field post then charged good, shut tractor off restarted and it didn't charge until I grounded field post. So I had a new 6 volt positive ground volt reg put it on started tractor no charge turned on lights no charge. Then I remembered that I needed to polarize it, so I shut it off, took jumper wire and touched gen post on reg to bat post on reg. Started it, no charge, turned lights on, no charge. What do I need to do to get this reg to work or will it work on this set up, or did I ruin this reg by starting it before I polarized it. I hooked everything up like the wiring diagrams show for the cut out system.

Janicholson · Feb 16, 2019

from what you have said, I need to explain: The F terminal on the generator needs to connect to the Field terminal on the regulator. The A terminal on the gen needs to connect to the Gen terminal on the regulator. The Bat to the amp gauge load side (not the battery side). The regulator needs a very good ground from its frame to the mounting point. The field is given electricity inside the generator, and the regulator grounds that circuit. If the regulator is not carefully grounded it will not work. Also any wire formerly attached to the light switch to the field terminal on the gen should be disconnected at both ends and taped off. The generator is already polarized because it charged. Polarizing puts magnetism into the field pole iron and allows it to start charging on its own. Jim

K-Mo · Feb 17, 2019

Referring to the original cut-out application.
The light switch should have two charging positions, the HIGH position grounds the generator field, the LOW position connects the field through a resistor to ground.
Connect a test light between the battery and the field terminal on the light switch. Operate the switch and the light should light in both the HIGH and LOW positions.
If no light, then the light switch is not grounded. The switch is grounded through the instrument panel.
Do you have the instrument panel mounted to the tractor? If not, Connect a wire between the panel cover and ground.
I helped a gentleman onetime with the same problem. To troubleshoot, he unmounted the the instrument panel cover. All we had to do was install the panel cover and problem solved.

redforlife · Feb 17, 2019

The A was originally a positive grounded battery system. For the cut out to work, you need to have good clean tight electrical connections throughout the system. The amp box and removable cover has to be well grounded. The cover that the amp guage and light switch are mounted to needs to be well grounded to the oval box it bolts to. Poor ground here is a common problem for the cut out system. If eliminating the cut out, and going with the regulator, you need to wire the regulator differently than the cut out. You need to eliminate the use of the light switch for one thing. The regulator eliminates the need to be wired through light switch. It takes over the light switch control and does it on it's own. The regulator is not wired exactly the same as a cut out. I think there is actually an extra wire for a regulator to work. You need to wire it the way a regulator is suppose to be.

Young Mechanic · Feb 17, 2019

Ok thanks for all the info folks. Sounds like I've probably got a ground issue, and need to change a few wires around. This is something I never had learned and needed somebody that knew what they were talking about to tell me.

Farmall A charging?

Young Mechanic

Member

Janicholson

Well-known Member

K-Mo

Member

redforlife

Well-known Member

Young Mechanic

Member

Similar threads