8N Electrical Problems

'49 8N with electronic ignition.
Was running. Battery went dead. Replaced (positive ground).
Tractor running, battery not charging. Cleaned all connections. New generator (old one confirmed bad), new regulator (polarized). Operated nicely for about 2 minutes; then back to -6/7 volts.
What am I doing wrong?

1, why not post on the ford N specific forum?

2, motor test genny.

if it passes, try a full field test.. if that produces no charge at the battery, then jumper cutout ( bat to arm ) and full field her at about 900-1000 rpm. check volts across battery and look at amp gauge

post back.

soudnguy

(quoted from post at 20:22:44 02/04/11) 1, why not post on the ford N specific forum?

2, motor test genny.

if it passes, try a full field test.. if that produces no charge at the battery, then jumper cutout ( bat to arm ) and full field her at about 900-1000 rpm. check volts across battery and look at amp gauge

post back.

soudnguy

Click to expand...

Thanks.

1. Link to the ford N forum?

2. 6.02v across battery with engine operating.

0 volts ARM to FLD on generator with engine running and All wires at gen disc.
0.7V GND to FLD

5.02V ARM to BAT on VR with all wires connected and engine running.
0.17V ARM to FLD

Heres a Troubleshooting Procedure that may help, but its only for Class A charging Systems

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

John T
John Ts Troubleshooting

(quoted from post at 07:19:02 02/05/11) Heres a Troubleshooting Procedure that may help, but its only for Class A charging Systems

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

John T
John Ts Troubleshooting

Click to expand...

Thanks, John.

The one point I did not check is to insure there's a good clean ground of the generator to the tractor frame. Gleaned the ground WIRE contact point on the generator and on the frame at the VR, but did not clean the gen to frame point. That's a critical ground, huh?

May the lack of a good ground of the gen to the tractor frame at the mounting bolt also explain why the amps on another tractor, while registering a charge - fluctuates rapidly between about 15-25 amps?

If an ammeter needle fluctuates around, that can be caused by several things like short genny brushes,,,,,,oily or carboned up commutator,,,,,,COMMUTATOR SEGMENTS NOT UNDERCUT PROPERLY,,,,,,weak or sticking brush hold down springys,,,,,,burned/resistive/carboned contacts in the VR,,,,,,,,,VR problems in general,,,,,,,corroded or resisitve or loose grounds or other wiring connections,,,,,,,,even an ammeter problem among even other things. NOTE Ive seen tractors that worked and charged fine even if at some RPM and dependant on battery charge the needle jumped around. Maybe the VR is just trying its best to regulate and it may not be an exact match for the genny its coupled to.

For sure the genny needs a good ground (to frame and eventually frame grounded battery post) as its output voltage is across its brushes, one of which is to the gennys case/frame.

PS My Troubleshooting is for Class A systems ONLY, I was thinking 8N's are Class A while some later Fords are B BUT IM NOT A FORD KINDA GUY

John T

Can you run a electronic ignition with positive ground?

(quoted from post at 10:55:23 02/06/11) Can you run a electronic ignition with positive ground?

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...Oh, it runs. Concern of mine is that the tractor has been started/used very, very little since EI was installed last October. Son doesn't pay any attention to guages, etc. When I fired it up last week, I noticed the tractor was discharging. Confirmed bad battery and alternator. Replaced, along with VR and resistor block. But, still discharging. Am curious about the EI wiring since I know nothing about which post it should have been wired.

(quoted from post at 11:01:54 02/06/11)

(quoted from post at 10:55:23 02/06/11) Can you run a electronic ignition with positive ground?

Click to expand...

...Oh, it runs. Concern of mine is that the tractor has been started/used very, very little since EI was installed last October. Son doesn't pay any attention to guages, etc. When I fired it up last week, I noticed the tractor was discharging. Confirmed bad battery and alternator. Replaced, along with VR and resistor block. But, still discharging. Am curious about the EI wiring since I know nothing about which post it should have been wired.

Click to expand...

....Okay, changing gears on y'all just a bit.
I will replace the generator tomorrow. It is my plan to mount the generator, but attach no wires. Then using a volt meter, check the generator.

Any danger to generator in checking the voltage in such a manner from ARM to FLD, then from GND to FLD?

Second, if, all goes well above and after fully wiring the generator I'm still getting no charge to the battery; how long (minutes/hours) can I expect to run the engine without burning up this (3rd) generator?

The gennys output is across ARM to case/frame. When its open unloaded it can reach fairly high, its to what voltage it raises the battery when it (a good load) IS attached that really counts.

If the genny isnt charging I dont see that alone as any cause to burn it up. Burn up is more caused by heavy charging and overloading. On a 3 brush genny the closer the third brush is set to the main brush the higher the charge rate.

John T

(quoted from post at 14:55:48 02/06/11) The gennys output is across ARM to case/frame. When its open unloaded it can reach fairly high, its to what voltage it raises the battery when it (a good load) IS attached that really counts.

If the genny isnt charging I dont see that alone as any cause to burn it up. Burn up is more caused by heavy charging and overloading. On a 3 brush genny the closer the third brush is set to the main brush the higher the charge rate.

John T

Click to expand...

Thanks. Hopefully, my recent generator was a bum generator and the guy will replace it. Wishful thinking, I suppose.