140 Generator problem

nc140man · Jul 7, 2011

I have been having problems with charging system on My '61 140. Still has original 6 volt system on it. Hasn't been charging properly, jumped the F term and got the generator to put out a good charge. Thought voltage regulator was bad, just replaced it, polarized it to the generator then started it up. Seemed to be charging fine, turned on lights, drew ammeter down a little but was still showing a positive charge. Shut it down. Thought everything was fine. Happened to to check ammeter when done and noticed a discharge. Checked volt reg and it was getting hot and so was the genny! Went to disconnect battery by the ground and something was drawing a lot of current! Isolated genny by disconnecting wires to it and tested the two terminals on it and showed zero resistance on ohmmeter? Something seems off here. Internal short in generator? Hope You guys can help! Thanks for the help in advance guys, You all have a vast store of knowledge and help!

Scott

John T · Jul 7, 2011

If it draws a heavy discharge when shut down and the genny gets hot THE CUTOUT RELAY IS STICKING CLOSED. In fact if you loosened or removed the belt the genny would spin like the DC motor it is........

Starting when the genny is at opposite polarity of the battery can damage a VR, you may wanna Polarize just to be sure then try it,,maybe the VR isnt damaged????

Its NORMAL if the armature is in place to get an ohm reading very low (almost like a dead short on a cheap meter) from the Gennys ARM post to case ground. If you ohm from FLD it should be more like 3 to 6 ohms to ground, however, as thats the Fields then to ground via the armature.

The Full Field test involves temporarily dead grounding the Gennys FLD post to grnd and if she charges then but not otherwise the VR is bad or its not well grounded MAKE SURE THE VR HAS A GOOD GROUND IT NEEDS IT TO WORK

Some VR's are labeled specifically for either POS or NEG ground, sure you have the right VR???

heres more if you need it.....

http://www.ytmag.com/cgi-bin/viewit.cgi?bd=farmall&th=665110

John T
John Ts Troubleshooting

nc140man · Jul 8, 2011

Thanks John. I'll start at the top of Your suggestions and work My way down. I'll let You know what happens/ Now, back to work!

Scott

nc140man · Jul 9, 2011

Ok, gave it a go. Tried the first suggestions and polarized the generator. Then went and polarized the regulator. Hooked wiring back up, no discharge! Fine, pulled ignition switch on, slight draw. Turned on lights, bigger draw, still not as much as before. Turned them all off, everything fine, no discharge. Started tractor, fired up fine, after a few seconds, starts showing a charge, good huh? Even tested output with meter, about 6.85 at the generator but only 6.72 at battery terminal on regulator? Normal? Let it run a few minutes still charging and no heat(did run with cover off regulator so I could observe while running)seems fine. Shut off tractor and it goes right back to high discharge on ammeter! Disconnected generator terminal to stop it from discharging and was a good spark! Still drawing at generator? Dang it!What to try?

Scott

Jim Becker · Jul 9, 2011

(quoted from post at 11:14:22 07/09/11) about 6.85 at the generator but only 6.72 at battery terminal on regulator? Normal?

To me, that suggests some resistance through the cut-out contacts in the regulator. Could cause the points to heat up and stick shut (same thing John T said a while back). You might try polishing those points with clean paper from a paper grocery bag, or if they are really dirty, filing VERY LIGHTLY with an ignition point file. Either way, give a small final rinse with contact cleaner or brake cleaner.

nc140man · Jul 9, 2011

Shouldn't be too dirty, brand new regulator but will try plain paper and a little brake cleaner and try again. Hooked it back up but haven't started it yet and it's fine until I run it then sticks closed I guess when shutdown? Weird when running it seems fine but switched off it discharges.

nc140man · Jul 9, 2011

Just went and checked, the cut out points do stick together for some reason, I manually opened them up and it stopped the discharge. Hopefully cleaning them will fix the problem!

Scott

pete 23 · Jul 10, 2011

Started a post on adjusting cut out, but it gets pretty tricky. Will just say, that spring tension on cutout and air gap from core to lever are what control it and is is normally adjustable. Reverse bucking current is what opens the cutout and spring tension and air gap both have effect on that and closing them. Actualy, I have seen new cutouts that were wired incorrectly and they constantly arced (sparked) while closed and charging. Needless to say they would not open when shut down. Had two one day guy brought in he had bought from parts store, slipped on one of ours, worked fine. At any rate, your cutout is not working as intended, wrong polarity or set or wired wrong internally.

140 Generator problem

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