Odd charging issue

[Dan]

Working on a 1950 8N with front mount distributor and still 6 volts. Has an older wiring harness on it, and I had to rewire and add the resister block as it was missing. Now, wiring is exactly as the I&T manual shows.

When I first got it, the generator was not charging. I found I could motor the generator so I bought a new regulator. After polarizing the new regulator I started getting 10 amps on the ammeter and voltmeter showed battery charging.

Now the odd part - at an idle and upwards to half throttle the ammeter shows 10 amps going up to 15 amps. An voltmeter check at the battery shows 6.4 volts and rising. A little over half throttle and the ammeter drops to -10 amps and a voltmeter at the battery shows 6.2 volts. Reving the engine to full throttle gets the ammeter to 0 volts or a little above at this point. If I shut the tractor off and restart the ammeter once again shows 10 amps and charging until I get over half throttle.

Checked the generator belt tension and it is tight. Runs and charges fine for the 10 minutes I checked until I have to throttle up. Does the regulator or generator have a cutout if amp draw gets too high?

 

[JMOR]

Working on a 1950 8N with front mount distributor and still 6 volts. Has an older wiring harness on it, and I had to rewire and add the resister block as it was missing. Now, wiring is exactly as the I&T manual shows.

When I first got it, the generator was not charging. I found I could motor the generator so I bought a new regulator. After polarizing the new regulator I started getting 10 amps on the ammeter and voltmeter showed battery charging.

Now the odd part - at an idle and upwards to half throttle the ammeter shows 10 amps going up to 15 amps. An ammeter check at the battery shows 6.4 volts and rising. A little over half throttle and the ammeter drops to -10 amps and a voltmeter at the battery shows 6.2 volts. Reving the engine to full throttle gets the ammeter to 0 volts or a little above at this point. If I shut the tractor off and restart the ammeter once again shows 10 amps and charging until I get over half throttle.

Checked the generator belt tension and it is tight. Runs and charges fine for the 10 minutes I checked until I have to throttle up. Does the regulator or generator have a cutout if amp draw gets too high?

Yes

 

[Dan]

Yes

Which one, generator or regulator- or both? What is the amperage cut off value if you know?

 

[Bruce(OR)]

Internet search JMOR wiring diagram. Your answer starts to lie there. What does that 6V system need a resistor for?
Sounds like your machine has been to Disneyland and worked on by the best mechanics. M-I-C, K-E--- Yeah I have one of those machines also.
I got mind from the local school district.
JMOR will have your nswer

 

[Dan]

Internet search JMOR wiring diagram. Your answer starts to lie there. What does that 6V system need a resistor for?
Sounds like your machine has been to Disneyland and worked on by the best mechanics. M-I-C, K-E--- Yeah I have one of those machines also.
I got mind from the local school district.
JMOR will have your nswer

Balast resistor and wiring block is stock equipment on a front mount 6 volt system N Series tractor. The balast resistor gives extra boost to the coil when cold, then pulls back as it warms up. Once again - OEM.

As far as the wiring, it was a standard after market wiring harness they just wired around the missing ballast resistor block as it was missing. Just a matter of moving the wires to the correct location once I put the resistor block in place. My wiring is now exactly as the I&T manual shows and I would assume that is correct.

 

[JMOR]

Which one, generator or regulator- or both? What is the amperage cut off value if you know?

If a 3 brush generator, it has built in current limiting.. If 2 brush generator, the VR has current limiting function, 3 brush = 11.5 amperes, and 2 brush = 20 amperes

 

[JMOR]

Balast resistor and wiring block is stock equipment on a front mount 6 volt system N Series tractor. The balast resistor gives extra boost to the coil when cold, then pulls back as it warms up. Once again - OEM.

As far as the wiring, it was a standard after market wiring harness they just wired around the missing ballast resistor block as it was missing. Just a matter of moving the wires to the correct location once I put the resistor block in place. My wiring is now exactly as the I&T manual shows and I would assume that is correct.

Good answer , Dan...but I also like 1) because that is the way Ford engineers designed it and 2) to keep coil current at a level suitable for reasonable coil and point life.

 

[Dan]

If a 3 brush generator, it has built in current limiting.. If 2 brush generator, the VR has current limiting function, 3 brush = 11.5 amperes, and 2 brush = 20 amperes

Great info, thanks! It is a 2 brush generator and I guess it is a cheapo VR limiting the charging at about 16 or 17 amps. That does seem high though for a new battery sitting at 6.3v before starting.

 

[quinnbrian]

9n doesn't it use a cutout switch? Not a voltage regulator?...I just went down this rabbit hole...switch everything back to 6 volt..12 volt "make over" was too messy..wiring running ..no were..lol .
Cheers
B

 

[JMOR]

9n doesn't it use a cutout switch? Not a voltage regulator?...I just went down this rabbit hole...switch everything back to 6 volt..12 volt "make over" was too messy..wiring running ..no were..lol .
Cheers
B

The man said, right up front, that he was working with 1950 8N. No mention of older 9N.

 

[Dan]

Ok, I have been searching the internet for several days regarding my issue and have found more than a few posts where the system charges fine for a few minutes, then drops to -10 on the ammeter, then goes to zero and stops charging the battery as mine is doing - so at least it is not a unique issue to just me. However, only 1 post had a solution and it was a slipping generator belt - not my issue. Two posts ended with statements that it was normal as the VR sees a charged battery and disconnects the generator to prevent overcharging. However, I never see over 6.4 volts at the battery while it is charging - not the ~7 volts I would expect.

Something still does not seem right.

 

[Dave G9N]

Great info, thanks! It is a 2 brush generator and I guess it is a cheapo VR limiting the charging at about 16 or 17 amps. That does seem high though for a new battery sitting at 6.3v before starting.

Generator - The History of the Ford Ferguson 9N Tractor Generator, by Tim Daley can be found at [ntracorclub.] com/howtos/pdfs/The-History-of-the-Ford-Ferguson-9N-Tractor-Generator.pdf

There is a picture on page 19 showing the early 8N generators. The first ones, 8N10000A with the front mount distributor were 3 brush and can be modified to a 2 brush as described in Service bulletin 78. As far as I have been able to determine (mostly by reading what JMOR and Tim had to say) the three brush generator, 8N10000A, was limited to about 11.5A and the two brush 8N10000B and C generators maxed out at 20A. With the third brush removed, all I can find is that the A revision could put out more than 11.5A. I have a 9N with a 8N10000A generator with the third brush removed and a Sparex S.67125 regulator, but the ammeter doesn't work, so all I know so far is that the battery does charge. I was unable to find a direct replacement for the 8N10505B regulator.

Which voltage regulator did you find? Sparex S.67125 is listed as equivalent to an 8N10000C, which appears to be correct for the 1950-52 8Ns.
https://us.sparex.com/catalogue_3d/60598/index.html?page=1 It is on page 91

 

[Dan]

Generator - The History of the Ford Ferguson 9N Tractor Generator, by Tim Daley can be found at [ntracorclub.] com/howtos/pdfs/The-History-of-the-Ford-Ferguson-9N-Tractor-Generator.pdf

There is a picture on page 19 showing the early 8N generators. The first ones, 8N10000A with the front mount distributor were 3 brush and can be modified to a 2 brush as described in Service bulletin 78. As far as I have been able to determine (mostly by reading what JMOR and Tim had to say) the three brush generator, 8N10000A, was limited to about 11.5A and the two brush 8N10000B and C generators maxed out at 20A. With the third brush removed, all I can find is that the A revision could put out more than 11.5A. I have a 9N with a 8N10000A generator with the third brush removed and a Sparex S.67125 regulator, but the ammeter doesn't work, so all I know so far is that the battery does charge. I was unable to find a direct replacement for the 8N10505B regulator.

Which voltage regulator did you find? Sparex S.67125 is listed as equivalent to an 8N10000C, which appears to be correct for the 1950-52 8Ns.
https://us.sparex.com/catalogue_3d/60598/index.html?page=1 It is on page 91

I purchased the VR from this site.

Ford 8N Voltage Regulator - 8N10505B

Ford 8N Voltage Regulator for sale, 8N10505B. For 8N - For Early Models with Front Mount Distributor, with generator. for sale. Item 105536

www.yesterdaystractors.com

If I have a front mount distributor but a 2 brush generator, can I use a VR for a later side mount distributor?

 

[Jim L WA]

JMOR and others. I have a question. If the generator or regulator decides to limit current, what is causing a -10 amp draw? Why wouldn't the ammeter just go to near zero?

 

[JMOR]

Excellent question. No good reason that I can think of, as only thing drawing current would be ignition and that is only a small part of 10.

 

[Jeff Hamilton]

I had similar problem. Not on an 8N, was an Ford 860, 6 volt. But same issue. Needed a VR, so I bought one from this site, it would charge like a bandit then stop. Finally smoked itself. I bought a "Standard Blue Streak' from O'Reilly's and it works perfect.

 

[Jim L WA]

I had similar problem. Not on an 8N, was an Ford 860, 6 volt. But same issue. Needed a VR, so I bought one from this site, it would charge like a bandit then stop. Finally smoked itself. I bought a "Standard Blue Streak' from O'Reilly's and it works perfect.

I'm glad you found one that worked. That was the reason I converted to an alternator on my NAA. I gave up after going through 3 regulators.

 

[Dan]

Ok, got a chance to work on this again today. I verified all genny to VR cables were not shorting to ground using my volt/ohm meter. I cut in new ends on the GND wire as half of the wires were broken going into the end connector crimp. Ohms were running around 0.6 ohms resistance end to end. Still running 10 amps at half idle. Wired around key switch and new balast resistor - no change.

What else can I test as to what can be causing such a high amp draw? Battery was at 6.23v before starting and slowly climbed up to 6.45v over 5 minutes of running. Battery is new (not that this means anything nowdays) but shouldn't a 2 brush generator jump up to 7v when running? As before, once the RPMs climb over half throttle and hits about 13 amps the VR cuts out as designed for this VR model.

Also, since I purchased an early 8N VR with a 2 brush generator, should I replace it with a later 8N VR that cuts out at 20 amps?

 

[Btzj02]

I know many people on this sight dislike using an Amp meter but maybe it is time to get it out and test the wiring, one at a time to find the 10 amp draw. My 6 volt 8N51 amp meter deflects only slightly negative once the battery is fully charged. The first Amp test I would do would be the wiring connected to/through the Amp meter to verify the draw. There are no short cuts, each wire circuit must be opened, one at a time, and the meter wired in series. (They do make clip on Amp meters but I have never used one.)

Question: Once the tractor is running and you are showing the 10 Amp drain did you measure the voltage on the cable between the solenoid and the starter and the small wire voltage connected to the starter switch?

I had another thought: It is possible to not only wire the Amp meter backwards but to wire it such that it will only measure generator output or a NET generator/battery power flow. (Some diagrams available are not always accurate or wire the Amp meter different than OEM with no mention of the difference.)

 

[Dan]

In researching my issue on the internet I am seeing most that do a before and after voltage reading on their batteries immediately sees about 7 volts with the engine running at half throttle. I never see that on my readings. I see about 6.2v before, and the voltage starts ticking up with the engine running. After 10 minutes or so it is at 6.45v so I know it is charging, but I never see an immediate 7v that I read about. Also, at 6.4v I am still seeing 10 amps on the ammeter and will increase with throttle until I hit about 13 amps and then the VR cuts out. Remember, I bought an early 8N VR by accident because I have a 2 brush genny in place so cutting out at 13 amps is normal for this VR. I just don't think I should be drawing that many amps at 6.45v.

It that normal?

The battery is a few months old and can sit for several days unhooked and shows about 6.3v so I would not "think" the battery is bad.

Also, I will verify amp draw with my multimeter when I get back to the tractor. I do have the wiring correct per the I&T manual.