John Deere 50 charging - must always equalize field

Flashy65

New User
I have a 1955 model 50 that has a new battery, volt regulator, new wiring and connectors. I have a good generator, with new brushes and a clean armature. If I equalize the field once started and running, it charges just fine. The problem is I must do this EACH TIME I start up the tractor and run the thing after it's been shut off. I do not disconnect the battery.

I am beginning to think the generator just isn't putting out as much as it used to.

Any help or suggestions?
 
Yep - still positive ground. I will check this. Is the voltage regulator not already screwed directly onto the generator?
 
Do you mean polarize instead of equalize? If so, then you polarize the armature, not the field. The polarization should be done BEFORE the
engine is running. To polarize the armature, touch a wire between the BAT and ARM terminals of the regulator momentarily and you should see a
spark. You say "it charges just fine" which means the generator is working correctly.

Clean the area on the generator (where the regulator fastens) of all rust and paint, then do the CORRECT polarization and it should work
correctly.
 
Yes Polarizing is what I am doing. If I do this when the engine is NOT running, it will not start up and charge correctly. If I do this while it is running, it will start charging again, reflected by the gauge as well as putting a meter across the battery.
 
Wrong!: Jumper wire from Bat terminal of regulator to the Armature terminal of the general unless you don't have the correct Generator (Delco)
 
You Polarize the genny by momentarily flash jumping from BAT on the VR over to GEN/ARM and you do that BEFORE START UP.

You can "full field" the gennys Field windings by jumping the gennys FLD or FLD on VR to frame ground. Such can allow a good genny to charge even if the VR is bad or its not well grounded.

You DO NOT jump BAT to FLD as you're doing and Im unsure what, if any, damage you might have done.

START ALL OVER AND DO IT CORRECT THIS TIME BY CORRECTLY POLARIZING THE GENNY BEFORE START UP

If she dont charge MY ADVICE IS TO work through my Troubleshooting Procedure instead of guessing and doing things incorrect which may damage something.

John T
John Ts Troubleshooting
 
Ron,

Don't want to get in a pi$$ing match with anyone but what I said is correct. Just because you jumper from tha battery to the ARMATURE terminal doesn't mean you are polarizing the armature. The field winding in the generator(Delco at least) is connected to the armature terminal inside the generator so therefore you are polarizing the field.

Just in case you doubt my credibility, I hold a degree in EE with 33 years of teaching electronics. Of those 33 years, about 20 were spent teaching a course in DC motors and generators. I have run numerous experiments in the lab polarizing generators. Many times we ONLY connected to the field terminals of industrial generators. In addition I an 72 yrs old and have polarized numerous farm tractor generators.

Oh and by the way, the armature generates ALTERNATING CURRENT which is changed to DC by the commutator. So you can't polarize the armature anyway.
 
Thanks. Seems that a lot of other people and "literature" are then teaching the topic wrong. I'm an EE as is John T who posts here and his info talks of ARM to BAT as the connection. My EE experience is in RF, professional mobile radio, radio and TV transmitters, military radar, and cellular phone infrastructure. Motor vehicle ignition and charging systems were learned by "seat of the pants" so I'm not THE EXPERT in that by any means. I understand what you say about armature as an AC generator with DC created from the commutator.

Thanks for the discussion. Got a few years on yah - I'm 78.

Wonder if they have figured out the cause of this original problem?

Ron
 
This is simplified diagram of a Delco Type A generator. Hot battery current is applied to the armature post on generator, current flows to/through armature and through the field coils, and in Type A from field post through the regulator to ground.

Polarizing current through the field coils magnetizes the pole shoes (iron cores in center of the field coils) one north pole and one south pole. Ground polarity of the battery determines direction of current flow which in turn determines which shoe is north and which is south. This in turn determines output polarity when generator begins to charge.

It is the pole shoes at center of field coils that are polarized.

Diagram from Delco-Remy Electrical Equipment operation and maintenance Handbook DR-324. Bulletin 1G-100, page 3 7-22-46
a197195.jpg
 
Thanks rvirgil_KS.

Can I make the comment that it seems like all commenters are basically right WITHIN WHAT THEY ARE SAYING??

But the "sayings" make it appear that some don't understand, but in their own way, they do understand.

Are these fair statements??

Ron
 
(quoted from post at 11:36:29 07/29/15) Thanks rvirgil_KS.

Can I make the comment that it seems like all commenters are basically right WITHIN WHAT THEY ARE SAYING??

But the "sayings" make it appear that some don't understand, but in their own way, they do understand.

Are these fair statements??

Ron
'll give you a great big WHAT? on that one! :lol:
 
You mean the old problem "I wonder if what I think I wrote is what you think you read". On these bulletin board sights one has to be patient with other people as we all have different background, different level of understanding, and often times terminology varies from one part of the country to another.

If we could sit down face to face for a few minutes, most questions would be resolved quickly.

I certainly wasn't trying to be condescending in my previous post. Just trying to give insight to question below from authoritative source (Delco-Remy).

I spent 38 of my 72 years in TV and Two-Way world so tractor circuits are quite simple to me. (Think what it would be if we had to add frequency to the equation.) I've learned a lot from the folks on this and other sites and still have a lot more to learn. In the end, in spite of all our limits in understanding, the real purpose is to get that old tractor running the best that we can.
 
I appreciate everyone's help here. I will return to the tractor barn between now and the weekend to report back. I am currently awaiting new brushes for the starter before I can do anything more with the generator and charging system.
 
(quoted from post at 16:37:57 07/29/15) You mean the old problem "I wonder if what I think I wrote is what you think you read". On these bulletin board sights one has to be patient with other people as we all have different background, different level of understanding, and often times terminology varies from one part of the country to another.

If we could sit down face to face for a few minutes, most questions would be resolved quickly.

I certainly wasn't trying to be condescending in my previous post. Just trying to give insight to question below from authoritative source (Delco-Remy).

I spent 38 of my 72 years in TV and Two-Way world so tractor circuits are quite simple to me. (Think what it would be if we had to add frequency to the equation.) I've learned a lot from the folks on this and other sites and still have a lot more to learn. In the end, in spite of all our limits in understanding, the real purpose is to get that old tractor running the best that we can.

Sometimes (and this may be one of them) when it really doesn't matter how the TV works as much as we need to know how to turn on the TV.
As was said earlier You Polarize the genny by momentarily flash jumping from BAT on the VR over to GEN/ARM and you do that BEFORE START UP
Just a thought :)
 
I've tried everything - no charging. It runs on the battery and shows a draw on the gauge.

What kind of voltage should I see coming from the generator terminals if it is a good generator?
 
(quoted from post at 17:35:51 08/02/15) I've tried everything - no charging. It runs on the battery and shows a draw on the gauge.

What kind of voltage should I see coming from the generator terminals if it is a good generator?
on't even both to try to measure with a digital meter! With an analog meter, the Armature terminal will be about one volt +/- a little with NO field current. If VR is OK with field contacts & nothing else prevents field current, then you can see several times normal battery voltage at ARM terminal when it is connected to nothing except your analog meter.
 
Where are you located?? Maybe some one who posts here would be close enough to give you a personal hand for a small fee.
 
I AM BACK WITH MORE NEWS

I've rebuilt this generator...

new coil packs
new brushes
new terminals
new voltage regulator

So with the generator back on, I equalized it with the key OFF.

-No charging

Next, I polarized it while running.

-THEN IT WAS CHARGING ONCE AGAIN!
 
Things I have noticed are:

After running the tractor a while, I had to re-equalize the field again. It's been OK since.

When the whole thing is charging as it should, I can look into the end of the generator and see some light blue sparks where the brushes touch the rotating armature contacts.
 

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