Farmall h ammeter not working.

Cecil09

Member
So the original ammeter had a crack in the glass so I wanted to replace it. Never really seem like it did anything anyway. I ended up replacing all the wiring from the generator back. Cleaned all the connections. Wired up the switch. And it fired right up, but the ammeter does nothing. I found the wiring diagrams on here and wired it as it should. From the battery to one side and the battery terminal on the generator as well as the fuse connection from the switch to the other side. I ran The F connection on the generator to The resistor on the bottom of the switch. As per some advice on here I ran a ground wire from the switch before the resister that the F wire is connected to, To A starter bolt. Tractor runs fine and it does not die after working it so I believe the generator is working but I don't know how to test how much it actually putting out. If anyone can help me I'd really appreciate it.
 
The generator should be putting out 6 9 to 7.2 volts into the battery , measured across the battery when running at 2/3 throttle.
If at 6.3 or less, no charge is taking place. Search on this site for John T charging system. Jim
 
Once an "H" is running, it will run with "juice" from the battery even if the generator isn't working so no assumption can be made that the generator is charging just because the tractor is running.
 
Current but surely it would die after brush hogging for 4 hours right? Even after that I turned it off and it starts right up.
 
I just read johns charging breakdown. Pretty good stuff there. I'll take it with me next time I'm out at the tractor. I'll touch base after sim checks.
 
If you own a tractor you should also own a multimeter. Even a cheap/freebie Harbor Freight one will do. Doesn't have to be a $300 Fluke professional setup.

The ammeter should twitch towards discharge when you turn on the ignition switch, and should move significantly toward discharge if you turn on the lights. It's possible the ammeter is defective, but not likely. Even the cheap ones from overseas seem to be pretty reliable out of the box.
 
(quoted from post at 04:30:06 09/19/17) If you own a tractor you should also own a multimeter. Even a cheap/freebie Harbor Freight one will do. Doesn't have to be a $300 Fluke professional setup.

The ammeter should twitch towards discharge when you turn on the ignition switch, and should move significantly toward discharge if you turn on the lights. It's possible the ammeter is defective, but not likely. Even the cheap ones from overseas seem to be pretty reliable out of the box.
Yes I own a multimeter
I do not have lights on the tractor yet. Just recently bought it. Still trying to get it all figured out.
 
Ok John. This is what I have. Please let me know if I need to change anything. Starting at the generator from the arm post to the gen post. Batt post goes to the load side of the ammeter. Load side of ammeter also goes to the 4 way switch. From the batt side of ammeter to the hot side of starter button. The 4way switch is grounded by a wire to the frame of the tractor. I ran a wire from the switch before the resistor that the field wire attaches to.

I also have an off on battery push pull switch that powers the ignition. So I have the wire from coil to the not hot side of that switch and the hot side goes to the hot side of ignition switch.

That's it for wiring I think. I do not have lights.
As for voltages o get 8+ on the batt post with 2/3 throttle
At the battery I get 6+with 2/3 throttle.
At the ammeter I get 6+ at idle and 7+ at 2/3 throttle.
Both posts on ammeter are hot. Batt post on generator is always hot. I have polarized the gen.
Tbe ammeter just sits at 0. No discharge when I pull ignition switch before starting. No charge when driving.
 
Correction. The wire from the coil goes to the switch from the switch goes to the fused connection on the four way switch not to the starter button
 

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