JD H Generator Questions

I've had both the cutout relay and light switch tested recently, and they supposedly both work. I have rewired the generator connections with new 10 gauge wire.

Based on past posts, I have bench tested the generator and gotten it to motor and speed up when the "F" field wire is disconnected. However, when on the tractor, I can only get a reading of about one volt output (using multitester connected to "A" terminal on generator and to ground cable). Needless to say the cutout relay isn't closing. I have tried grounding out the field terminal without any luck. What could be going on? Thanks for the help.

When you said you werent gettign any voltage off the gens A post, if its connected to the relay and the relay has a short, it would BOTH kill the voltage PLUS cause the relay to never pull in.

Let me know. Ol John T

First, be sure the belt is good and tight and the belt is not slick and glazed.

1) Be sure the generator is getting a good ground connection by running a wire direct from the batterys grounded terminal to the frame of the generator and see if she will charge then.

2) If she still wont charge, leave the generator frame ground attached, and ground the field post (even though you already tried it once, try again)

3) If she still wont charge even with the field grounded, by pass around the cut out relay i.e a wire off the gens A post over to the battery side of the cutout relay and see if she charges. Thats the same effect as the cutout relay were closing. It shouldnt close by itself until the gens output voltage rises higher than the battery if its okay and working.

4) If she still wont charge, are you sure the wire on the battery side of the cutout relay is ALWAYS HOT and has a good continuous path to the non grounded battery terminal????? ? It cant charge the battery if its not got a connection to it. The wire on the battery side of the cutout relay must show battery voltage relative to ground. It gets to the battery through an ammeter if you have one, and then either to the starter post or direct to the battery itself. If it has an ammeter, it should read and ohm out like an almost dead short 0 ohms. If one side of any ammeter shows battery voltage, but none on the other post, the ammeter is bad open and the generators output is never gettign to the battery.

If the generator is turning, and its well grounded, and the field post is grounded, and theres battery voltage on the battery side of the cutout relay, and theres a good connection to the battery via any good (NOT OPEN) working ammeter, and she still wotn charge, I suspect the generator may be bad EVEN THOUGH MOTORING USUALLY MEANS THEY ARE GOOD. If its a 3 brush generator, the closer the 2 brushes are the higher its output, but even if set away, it should still charge.

Try this and let me know what you find. You may well just have a bad or shorted wire between the cutout relay and any ammeter to the battery terminal somewhere which is drainign the generators output and pulling it down. Also, what condition is the battery in??? a dead or shorted cell in it can wreak havoc on the charging system. Try things with all other loads disconnected like lights etc which could be shortign things out.

God Bles the USA

John T Nordhoff in Indiana

After going through the suggestions given, the problem was that the generator case needed to be grounded better. After running a wire from one of the mounting bolts to the ground cable, the cutout snapped shut and it started to charge! I had shined up the mounting bolts and surfaces when I put the generator on, but it must not have been good enough.

I now get about 7 volts off the cutout "A" terminal with the light switch in, and about 8.5 with the switch in the high charge position.

Thanks again.

~Did you check for voltage on the [A] post with the [F] post grounded? If not try that..

~You might have the generator polarized backwards if you did the motoring test off the tractor...

~To re-polarize...

~First, ground the [F] post

~Then, jump battery power from the NON GROUNDED battery post to the generator [A] post, you should see a spark & if so it's polarized.

~If the above doesn't get it charging make sure the movable 3rd brush is rotated as far as possible in the generator turning direction.

~If still no charge, check all the generator wires between the light switch & generator, the cut-out & generator for opens, then check the cut-out for a good clean ground.

~Then check for battery power at the battery side of the cut-out.

~It wouldn't hurt to check the light switch for a good ground but when you grounded the [F] post you by-passed that part of the system..

~If still no charge, make sure you have the correct generator that is turning the correct direction for your H....