Farmall H generator

Hi Guys back at Generator again today Bob and Janicholson thanks for previous reply generator is charging but still showing 18amps on amp meter and 8.6 volts at battery is it over charging doesn't seem to cut out at all battery voltage reading 6.3 with engine switched of it as though the field is not working also generator running very hot I think can barley put you hand on it.any ideas thankyou. changed the regulator again today berfore I started polarised and all.

Disconnect the field lead from the gen. & regulator. Use a multi-meter on ohms--RX1 scale, & have one lead on either end of the wire & one lead on ground [frame]. what is the reading? 0 Ohms or a dead short means the wire is grounded somewhere. Infinity on Ohms means that you will have to pull the lid on the regulator & take a look at the contacts. Or, you have a short [ground] at the generator F terminal.

If its ALWAYS fully charging Im thinkin like Brownie the genny itself may have a permanently grounded Field (at or near F terminal) or else the Regulator or light switch controller (whichever it has) may be permanently dead shorted relative to the Field control circuit.

See what it does if you remove the wire on the gennys FLD post????????????? If it still charges full theres an internal short in the gennys Field wiring PERHAPS AT THE F POST BECAUSE THE NUT WAS OVERTIGHTENED!!!!!!!!! From the gennys FLD post to its case frame there should be like 2 to 4 ohms representing the sum of the 2 fields in series HOWEVER its like zero ohms look for a short possibly cuz the nut was overtightened or theres an internal short from the field winding to case frame

If she goes to low or no charge with the wire removed from the gennys FLD post but ALWAYS charges at max otherwise, I suspect a bad/shorted voltage regulator or a short in the light switch or wiring to the light switch if its a cutout relay and light switch system.

If its a 3 brush adjustable genny and the third brush is set to full high charge that could also be a problem buttttttttt I suspect one of the 2 problems above.

Its the correct voltage genny for your system right?? NOT a 12 volt genny??

John T

well spent all afternoon doing all the usual checks it is a 6 volt geny with fixed 3rd brush and regulator I suspect a field gone in geny stripped and rebuilt brush end every thing looked ok fitted geny with no belt run power through a terminal and motored fine changed speed when I earthed field fitted a brand new regulator and wired up polarized etc fired her up and no charge fitted old regulator and no charge tryed checking ohms from field was running all over the place no good reading stripped off belt and regulator power to A terminal motored in correct direction but very slow earthed F terminal and took off at speed in opposite direction took off earthed f and stood still motored slowly with a push geny out I reckon yes No ??? Why else would the geny be running so hot earlier when it was puting out 8.6 volts thanks for any thoughts

Just thinking through this---the field wire & armature wire aren't interchanged are they?--between the reg & gen??

possibly on the inside with brush wires going out to check thanks for response

The gen is basically working correctly. You are having trouble shutting it down. That 18 amps at 8.6 volts is running 154 watts, so the gen is going to get hot. Like John T said--remove the F wire from the gen & see what the charging rate does.

Are you housed up near Eastern Iowa, by any chance? This charging problem really intrigues me. The laws of physics & electricity don't vary [much]. I'd come over if you were near just to see this generator - regulator thing. Is the reg mounted on the gen??

I agree with Brownie/John, an internally grounded field would do all of the above. With a piece of plastic under the third brush, the field should show less than 3 ohms, From the F terminal to the third brush. It should not have any connection to the generator case. Infinite Ohms to case from either end of the field circuit. Jim

had it all apart again checked everything only parts I haven't had out or apart is the actual field windings nut F terminal insuation and bolt in good condition is it possible windings are damaged /broken or tape is gone and winding is touching case

Check ihms between the Frame and Wire. No conductivity (good) Any conduction (BAD) Jim

It may be wired wrong inside the gen. Those two little wires are crossed when attached to the brushes correctly. Check it with the band off. You don't have to have it apart.