Charging problem-wiring or generator?

[Dr. Bert]

9N 6 volt front mount. Rebuilt this tractor- new wiring harness, new generator, new cutout, new resistor block and new ammeter.With the wire from the BAT terminal on the cutout to the charge post of the ammeter, when I turn on the key the ammeter shows 10 amp charge!! Start the engine and the needle returns to zero. Switch wires on the ammeter and with the key on-10amps discharge and returns to zero when I start the engine.At the generator a voltmeter shows it generating 12 volts, but across the battery terminals very slightly over 6 volts!
Double checked all wiring using a wiring diagram that Dunk posted here. Also, checked it against a running 9N--all correct. Even switched cutouts to see if that was the problem--same results.An old Ford mechanic mentioned that I might have received a generator wound for a negative ground 6 volt system. Is that a possibility? Another suggested just switching the battery cables.
Can anyone give me a clue as to why I have to switch the wires to the ammeter to get it to show discharge when the key is on? And when the engine is running at half throttle the ammeter needle will not show a charge? Any thoughts on that? Sorry this is so long. Thanks.

 

[Anonymous-0]

Did you Polarize the system? You mentioned everything except that.

 

[JMOR]

(quoted from post at 22:49:42 07/14/10) 9N 6 volt front mount. Rebuilt this tractor- new wiring harness, new generator, new cutout, new resistor block and new ammeter.With the wire from the BAT terminal on the cutout to the charge post of the ammeter, when I turn on the key the ammeter shows 10 amp charge!! Start the engine and the needle returns to zero. Switch wires on the ammeter and with the key on-10amps discharge and returns to zero when I start the engine.At the generator a voltmeter shows it generating 12 volts, but across the battery terminals very slightly over 6 volts!
Double checked all wiring using a wiring diagram that Dunk posted here. Also, checked it against a running 9N--all correct. Even switched cutouts to see if that was the problem--same results.An old Ford mechanic mentioned that I might have received a generator wound for a negative ground 6 volt system. Is that a possibility? Another suggested just switching the battery cables.
Can anyone give me a clue as to why I have to switch the wires to the ammeter to get it to show discharge when the key is on? And when the engine is running at half throttle the ammeter needle will not show a charge? Any thoughts on that? Sorry this is so long. Thanks.

WHAT the el is "charge post of the ammeter,"? Show us a wiring diagram.

 

[Dr. Bert]

On the back of the ammeter are 2 posts--one on the side that shows charging or + and the other post discharge side or -. Understand??

 

[Dr. Bert]

Yes I did. Sorry, I did forget to mention that.

 

[lha]

Is the pos+ cable grounded?If not, ground the pos+and polarize the gen.get an analog meter[with a needle],then read the voltage [not running]then start up ,check again at batt.if you don't read +-6.5v,adjust 3rd brush at rear of gen. That should get you about 6.7+-,don't adjust too high,or you'll boil out your batt.---lha

 

[Dell (WA)]

Bert......you write....."An old Ford mechanic mentioned that I might have received a generator wound for a negative ground 6 volt system"......stay away from that mechanic. He don't know what he is talking about. Generator output is determined by "POLARIZING"!!!! Understand???

You write......."Can anyone give me a clue as to why I have to switch the wires to the ammeter to get it to show discharge when the key is on? And when the engine is running at half throttle the ammeter needle will not show a charge? Any thoughts on that?".......my guess you have a FAULTY ammeter. New ammeter $10 (cheap)......Dell

 

[Dr. Bert]

Iha: Yes, the positive cable is grounded and I did polarize the generator and my analog meter did show some over 6 volts, but not 7. Maybe the system is charging (battery fully charged?). However, I am still puzzled about how the ammeter reads. The wiring diagram I used just shows wires going to the back of an ammeter as you face it, so assume the cutout to gauge wire is attached to the post of the right or + side of the ammeter. Wired like that, the gauge shows 10 amps charge when the key is turned on and before starting the engine--then the needle goes to zero with the engine running.

 

[Dr. Bert]

Dell (WA) . Thanks. Never even considered a faulty ammeter. Makes sense. Will try another one.

 

[lha]

Dr.Bert,after you get a new ammeter[did't think of that,even though I replaced mine recently]if it doesn't fix your prob., take the gen,cutout to a "mom&pop"starter and generator"shop and let them look at them,you might find they can help you with your problem.---lha

 

[JMOR]

(quoted from post at 22:49:42 07/14/10) 9N 6 volt front mount. Rebuilt this tractor- new wiring harness, new generator, new cutout, new resistor block and new ammeter.With the wire from the BAT terminal on the cutout to the charge post of the ammeter, when I turn on the key the ammeter shows 10 amp charge!! Start the engine and the needle returns to zero. Switch wires on the ammeter and with the key on-10amps discharge and returns to zero when I start the engine.At the generator a voltmeter shows it generating 12 volts, but across the battery terminals very slightly over 6 volts!
Double checked all wiring using a wiring diagram that Dunk posted here. Also, checked it against a running 9N--all correct. Even switched cutouts to see if that was the problem--same results.An old Ford mechanic mentioned that I might have received a generator wound for a negative ground 6 volt system. Is that a possibility? Another suggested just switching the battery cables.
Can anyone give me a clue as to why I have to switch the wires to the ammeter to get it to show discharge when the key is on? And when the engine is running at half throttle the ammeter needle will not show a charge? Any thoughts on that? Sorry this is so long. Thanks.

You say:
1) With the wire from the BAT terminal on the cutout to the charge post of the ammeter, when I turn on the key the ammeter shows 10 amp charge!!
2) On the back of the ammeter are 2 posts--one on the side that shows charging or + and the other post discharge side or -.
3) so assume the cutout to gauge wire is attached to the post of the right or + side of the ammeter. Wired like that, the gauge shows 10 amps charge when the key is turned on and before starting the engine-
4) The wiring diagram I used just shows wires going to the back of an ammeter as you face it, so assume the cutout to gauge wire is attached to the post of the right or + side of the ammeter.
5) Can anyone give me a clue as to why I have to switch the wires to the ammeter to get it to show discharge when the key is on?

Your comments above, mine below.

RE: #4, it appears that you have identified the + terminal (you called 'charge post') by assuming that it is on same side of meter as the charge indication is on the face of dial.
This is not a reliable method of determining the + terminal. If it isn't marked on the back, at the terminal itself, then you don't know.

RE: #1 & #5, Why? Because the terminal that you have identified as + is actually the NEGATIVE terminal.

It would have been nice to see the diagram that you wired by, but........
The ammeter, in a POSITIVE ground system should be wired as follows: ammeter POS terminal to BATTERY NEGATIVE (on your 9N that connection is at starter switch).
The ammeter NEGATIVE terminal to the cut out BATT terminal (which is common with 3rd terminal of resistor block/all loads such as ignition, lights, etc.)

Comments: 10 amps is very high for just ignition. IF really that high then don't expect to see a 'charge' indication because that is the full capacity of your generator (actually 11.5A when HI/LO is at maximum HI), therefore total generator output is being consumed by ignition & virtually nothing left over to be charging the battery, thus zero battery charging current.

Ign current probably not more than 6 or 7 amps stalled/cold & ammeter just no more precision than that. Gen HI/LO setting is probably not at maximum HI.

Hope all that is helpful.

 

[don b 1]

Doc....you say.....At the generator a voltmeter shows it generating 12 volts, but across the battery terminals very slightly over 6 volts!
If you have a 6v battery.....you don't need a 12v genny,maybe 7.5 volts.
The plus and minus shown on the back of an amp meter is just for the polarity of the meter,not the polarity of you tractors electrical system. don b1

 

[souNdguy]

gennies can be polarized to charge neg or pos grnd.. so disregard whoever told you it may be the wrong ground genny.

I'd look for shorts in the ignition wire, and also replace that ammeter.. it may be bad.

you want a slight negative deflection with key on, points closed and engine not running, and then when engine running, you want to adjust the genny for a slight positive deflection.

post back.

soundguy