# Ford 8N generator short



## elitopus

Hi
I’m helping my dad work on his 1950 Ford 8N. He said that starting last year, it was draining the battery between uses, and would have a decent sized arc when he hooked up a battery to jump it. 

This year I helped him take it out of winter storage. I can see when I hook up the battery the generator moves the pulley a little when the battery is first connected. The arc at the battery terminal is big enough where it wants to weld the terminal to the battery. So, there is a short somewhere. 

I took the positive (I know, negative ground), I mean, the output terminal off the generator and the arc goes away. 

So, is there likely a short inside the generator? Is it finally time to upgrade to the 12v system? Thanks for any info you might have.


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## harry16

Howdy elitopus, welcome to the forum. 

I suspect that you have a stuck regulator contact (battery connection). It should be open when the tractor is not running.


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## elitopus

Ok thanks. I assume the regulator is inside the generator?

Can it be taken apart and the contact cleaned?


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## pogobill

The regulator should be under the dash. 
http://www.fixthatford.com/index.php?main_page=index&cPath=3_42_171
Item 10505.


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## elitopus

Awesome. Thanks, I found it.


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## elitopus

I’d say someone has messed with it before me. Looks to only have 1 out of 3 mounted bolts installed.


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## pogobill

Close enough!


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## elitopus

I took out the regulator and popped the cover off (it had two small rivets I drilled out). Inside are two coils. One contact is spring loaded open, the other is spring loaded closed. Both springs seem to work as they should. 

Everything looks to be in good shape under the cover. So, I’m thinking maybe a short in the wire that goes from the generator to the regulator, or to the battery.


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## pogobill

You may need to polarize your regulator now and the generator.


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## elitopus

When you say polarize my regulator and generator, are you saying to make sure they are hooked up correctly and not backwards?

If I understand how the regulator works, the coil that is usually open is closed when the tractor starts. It has a smaller coil so that regular 6vdc can hold it closed.
The coil that is usually closed will open If the generator is over charging the battery, and it has a bigger coil to energize at a higher voltage.
Sound right?

I asked my dad what work has been done to the tractor. He has owned it for about 5 years, and bought it from a family friend, who I believe bought it new.
I know the key ignition was replaced at some point, and I’ll have to ask him if it was at the same time he started having this issue.


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## Hacke

The contacts on your cut out relay look crusty, dress them flat and shiny with a fine sand paper
Watch this:





Reconnect the relay as it is, do not forget to ground the metal base.
Check how the contacts work with engine off and on.


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## elitopus

Thanks. That was a pretty good explanation in the video. I’ll clean the contacts and check for correct operation.


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## pogobill

elitopus said:


> When you say polarize my regulator and generator, are you saying to make sure they are hooked up correctly and not backwards?


https://www.tractorforum.com/threads/tractor-not-charging.35688/#post-251168
Post #8


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## Dennis M. Raines

Unless you truely enjoy old electronics, do yourself a BIG favor and convert to 12 volt,alternator-with-internal-regulator. All you need is a battery, alternator and bracket, and a coil resistor (or coil with resistor). It will start twice as fast, and your charging problems are instantly solved. ...and if you have lights, change the bulbs to 12-volt.


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## JTB

If you notice the points on the large wired coil look like they are stuck together separate them and your short should go away. Try this. Also clean them with a point file or burnishing file. This part of the regulator is called a pull in coil and the points only touch after it is started.


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## John Liebermann

I may not remember voltage regulator operation but I don't think if the engine isn't running any points should be closed. What I would do is either put on a new regulator or do what Dennis suggested earlier and convert the whole mess to 12 volts


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## elitopus

I haven’t had a chance to try and polarize the regulator like was mentioned earlier. I did clean the contacts on the regulator. 

The contacts on the large coil are open, although it might be hard to see in the picture. 

I also checked out the wiring on the tractor. The wire that goes from the battery to the regular is good, and doesn’t ring to ground. The wire to the generator is the good also. The wire that goes to “field” rings good to the field terminal on the generator, but also rings to ground. I assume it’s supposed to with the tractor off? 

Also the ignition wires are wires correctly on the switch. There is continuity when the switch is on, and no continuity when the switch is off. 

At this point the tractor needs a new battery anyways. It was dead so many times last year that it doesn’t want to take a good charge. So, now would be a decent time to convert to 12v, but I’d like to make sure this shorting issue isn’t something that will bite me later on, if I don’t figure out what it is now. 

I was looking at conversion kits, and it seems for the older 8N tractors it’s around 165$, plus the cost of the new battery. 

I’m planning on working on it this weekend. I’ll install the regulator with the cover off and see what the contacts do when I hook the battery up.


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## Drifter444

elitopus said:


> I haven’t had a chance to try and polarize the regulator like was mentioned earlier. I did clean the contacts on the regulator.
> 
> The contacts on the large coil are open, although it might be hard to see in the picture.
> 
> I also checked out the wiring on the tractor. The wire that goes from the battery to the regular is good, and doesn’t ring to ground. The wire to the generator is the good also. The wire that goes to “field” rings good to the field terminal on the generator, but also rings to ground. I assume it’s supposed to with the tractor off?
> 
> Also the ignition wires are wires correctly on the switch. There is continuity when the switch is on, and no continuity when the switch is off.
> 
> At this point the tractor needs a new battery anyways. It was dead so many times last year that it doesn’t want to take a good charge. So, now would be a decent time to convert to 12v, but I’d like to make sure this shorting issue isn’t something that will bite me later on, if I don’t figure out what it is now.
> 
> I was looking at conversion kits, and it seems for the older 8N tractors it’s around 165$, plus the cost of the new battery.
> 
> I’m planning on working on it this weekend. I’ll install the regulator with the cover off and see what the contacts do when I hook the battery up.


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## Drifter444

Keep your 6volt. If everything is set up right, the 6 volt system is great. I have a 48' 8n, 6volt, and it will start year around. I hate it when people take away the original system, and go to 12v.


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## elitopus

This is how I see it. This is a second tractor. It has a mower hooked up all the time, because my dads other tractor (a little JD with a loader) has a backhoe attached all the time. 

The 8N is used in the summer to mow a field. Then it sits in the barn all winter. If I have to start replacing parts on the 6 volt system, it would make sense to me to put that money towards upgrading to a 12v system. 

If it was something simple like a shorted wire, I could see just keeping the original system. He already needs a new battery, so we are waiting to see what I figure out with this issue before buying one. 

So in my case, it seems like the generator is working. The regulator seems to be hooked up right. The wiring seems good. It’s my understanding that the voltage from the generator is what energizes the coil in the regulator, and that allows power to go from it to charge the battery. So then once the tractor is turned off, the coil opens again disconnecting the generator from the battery. 

This tractor has always been jumped with a 12v battery, so my concern is something got fried at some point. 

I’m going to play with it today and see what I can figure out.


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## pogobill

I'm wondering why the battery is always dead? There is not a whole lot of wiring on an 8N. When you jump the tractor, are you jumping it at the starter or through the battery? Through the battery.... don't do that. With the 8N's, when the tractor is started, the engine RPM's need to be rev'd up in order to excite the charging system to start generating power to feed the battery. If you don't, the battery will most likely not charge. Watch for your ammeter to kick in.


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## Hacke

Think of your regulator as two relays, which it is.

The cut out relay, which switch on/off the connection between generator and battery.
If this does not have an open contact when the generator stops, you will get the problem you described. The battery will then feed the generator, that acts as a motor, which you described. Even a small piece of material between the contact tip could start the effect. The contact may well be open now, but could have been stuck together and got free when you handled the regulator and took it apart. A few knocks on the regulator housing could have opened it.

Then there is the regulating relay, which lowers the generator voltage to a level suited for the battery. As mentioned in the video, the relay switches on and off rapidly (it buzzes). The regulated voltage depends on the tension of the spring that holds the contact tips closed.


There is nothing to polarize in the regulator. It is the generator that may need polarizing. There is not permanent magnets in the generator, just iron chunks with electrical windings (field windings) around them. However, the iron needs to have some magnetism left in order to start the production of electricity. Under normal operation, some magnetism will stay in the iron between starts. If the generator is new or has been sitting for a longer while, the iron can be out of magnetism. Then you need to "charge" the iron by a short shock of current through the field windings. The current has to go the right way in order to give the magnetized iron it's correct north and south poles.

I believe this type of regulator is what is called an "A curcuit type" with "Externally grounded field".
Instructions for polarizing the generator:
https://www.thecj2apage.com/forums/uploads/1568/polarizing_pictorial_2.jpg


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## JES2

You may want to try a new battery before doing a lot of work. You said that battery has been dead and charged a few times. That battery could have a reverse charge. That's where the positive and negative have switched . At least check the old battery with a digital volt meter it will show you which is positive and negative . If you change it to 12 Volts it will save you starter drives and starter ring later on by either having your old starter changed to a 12 volt or buy a new 12 volt starter that is available for the N tractors now.


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## elitopus

So today I went out and installed the regulator. I had cleaned the contacts with sandpaper and contact cleaner. Also when I installed it I made sure the 3 wires were not touching each other (even through insulation). I know sometimes the insulation can be worn through from vibration. 

Anyways, no arc when I hooked the battery up. I polarized the generator per the manual, and started up the tractor. 

Now when I disconnect the battery and hook it back up, there is no more arc, and the generator doesn’t move. So, it was probably like some have said, a stuck contact in the regulator. And me opening it up and cleaning the contacts fixed that problem. 

My dad is happy the problem is fixed, and he plans on using the tractor to mow the field tomorrow. Thanks for all the help guys.


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## elitopus

Just wanted to add that the battery was dead a lot last year because there was the short to ground through the generator, and my dad didn’t unhook the battery when he was done using the tractor. So every time he went to use it again the battery was dead.
We put it another 6 volt battery and I think have resolved the issue. I’ll find out when he goes to start it today.

Also what’s this about charging a 6 volt battery to 12 volts? Is that a thing?


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## pogobill

I don't think that's a thing!! 6 to 12! I have two 8N's and I do have to rev the engine up to get the battery to start charging. I watch y ammeter. Something to think about......


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## elitopus

I misread a post that said “change it to 12v” and I thought it said “charge it to 12v”. My bad.  I thought that sounded a little crazy too. 

My dad used the tractor for about 2 hours to mow today. It started right up when he got it out of the barn.

So then comes my second issue with the tractor. This is something that has happened since he owned it.

The tractor will run great for about 2 hours, then he says it feels like it starts to lose power, and then it just dies. If you wait until it cools off it will run for 2 hours and repeat the same thing.


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## FredM

check the coil and condenser.


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