Generator/ regulator testing Negative Ground 6v

R

RuleHard

Junior Member
I’m having some charging issues this year and previously I have not had any issues charging so the issue is not relayed to the way it’s wired but I just replaced the overdrive. My car has a negative ground so the information for testing the generator seems like it may not be exactly right.
For exam it says to ground the field terminal to bypass the regulator and go full charging. But I’m assuming that’s with a positive ground. So do I connective positive to the field terminal?
Mainly what I’m finding is that my charge meter will be indicating normal which was middle to just over middle as revs increase. Then it’ll start dropping to full draw then just below middle in the draw area and my overdrive quits working because the relay won’t close.
I have a rebuilt voltage regulator and generator but I want to actually
Test and diagnose the issue instead of throwing parts at it. Just how
I am.
 
Not enough information yet.
What year car?
On original Ford 3 relay regulators the field has to get power instead of ground.
On 3 brush generators that can have a regulator instead of just cutout the field wire gets grounded.
 
Kurt in NJ said:
Not enough information yet.
What year car?
On original Ford 3 relay regulators the field has to get power instead of ground.
On 3 brush generators that can have a regulator instead of just cutout the field wire gets grounded.
Click to expand...

This a 1953 ford customline club coupe. It has the battery hooked up negative ground. It always worked so I left it that way. Would I still ground the field terminal even if I have a negative ground? Also the regulator is a 3 relay. 1 current, 1 voltage, and 1 cut out. When I’m referring to charge and draw I’m referring correctly even though my meter in the dash is backwards.
 
To my knowledge, the '53s had pos. ground, so if the ground was changed to neg., wouldn't the ammeter read backwards indicating discharge when the system is actually charging? Unless, when the battery polarity was switched, the connections to the ammeter were reversed?
 
I would suggest going back to positive ground before doing anything else.
 
Last edited:
51woodie said:
To my knowledge, the '53s had pos. ground, so if the ground was changed to neg., wouldn't the ammeter read backwards indicating discharge when the system is actually charging? Unless, when the battery polarity was switched, the connections to the ammeter were reversed?
Click to expand...

Yes it does read backwards. I’m taking that into consideration.
 
tubman said:
I would suggest going back to positive ground before doing anything else.
Click to expand...

That’s what I plan to do but I think I need to re polarize the generator. I was trying to diagnose my issue first. Then install new generator and regulator.
 
ndnchf said:
Here is my video on polarizing a Ford 2-brush 6 volt + ground generator. This procedure applies power, not ground to the fields. To polarize for negative ground simply swap the + and - leads.

https://youtu.be/Rl9KY4wTHm0?si=hrLGaNBGZEmP8ami
Click to expand...

That video was helpful. I have never seen a 3 brush generator before.
Tonight I reversed my ground polarity and. Polarized my generator accordingly. I installed a rebuilt generator and rebuilt voltage regulator.
I’m taking my old stuff to the auto electric shop to get tested. I couldn’t start the car though because I believe my fuel pump is running backwards. Car also had an old 6v electric pump.
 
My '50 is 6v neg. ground. Grounding the field terminal to the ground terminal bypasses the regulator. Was the ammeter reading properly before you replaced the O/D?
 
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