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positive or negative ground?

C

crankyfranky

Member
working on my new to me 1963/4 ford 2000 4 cyl tractor and the battery is installed with the negative ground. the coil is also installed for a negative ground system so i think the previous owner may have converted the tractor from Positive to Negative ground for some reason. the charging system appears to be in good condition but isn't charging. the tractor has sat for many many years with a dead battery and probably needs flashed. but since the previous owner passed away many years ago i can't ask him what he was up to and have to figure it out. my question is was there a different voltage regulator for a negative ground system or will the original work either way. my regulator appears to be new and is the three terminal type with field/arm/batt connections. before i proceed to flash the armature to the battery is there anything i need to consider???? Thanks
 
On that model, the VR doesn't care neg or pos ground, but because so many people generalize, I will add that there are VRs where polarity does matter.
 
The old regulators did not care about polarity, make sure it has still has a generator on it before doing any flashing. Anything solid state DOES care about polarity. Do make sure the coil polarity matches the battery polarity or you will have a slightly weakened spark.
 
You don’t mention whether it has a generator or alternator. If it has an alternator conversion, it is 99% certain to be negative ground.
 
(quoted from post at 14:55:45 07/26/20) You don t mention whether it has a generator or alternator. If it has an alternator conversion, it is 99% certain to be negative ground.
Click to expand...
..and this didn't give you a clue??? " my regulator appears to be new and is the three terminal type with field/arm/batt connections. " :roll:
 
JMOR is that directed at me? I guess you never saw any jackleg 12v conversions where the rocket scientist that performed the surgery left the VR
wired in?
I can tell you with all certainty that I have. And a high percentage of them get sold shortly thereafter because the perpetrator isn’t smart enough to get
help.
So I think it is a legit question even if you don’t approve.
 
(quoted from post at 16:46:54 07/26/20) JMOR is that directed at me? I guess you never saw any jackleg 12v conversions where the rocket scientist that performed the surgery left the VR
wired in?
I can tell you with all certainty that I have. And a high percentage of them get sold shortly thereafter because the perpetrator isn t smart enough to get
help.
So I think it is a legit question even if you don t approve.
Click to expand...
n which case the VR is then just a terminal block and all is just fine. Seen one run like that for >25 years.
 
(quoted from post at 16:02:03 07/26/20) So it would be helpful to know if the tractor has a generator or alternator.
Eye roll.
Click to expand...

sorry .... yes it still has the generator.. and yes the ignition coil has been rewired to negative ground. Thanks you all. i will try flashing the system to see if that helps. one more thing......
on this three terminal VR do i need to remove the wire at the VR terminal or can i use a jumper wire to flash and leave the VR connected???
 
(quoted from post at 19:43:53 07/26/20)
(quoted from post at 16:02:03 07/26/20) So it would be helpful to know if the tractor has a generator or alternator.
Eye roll.
Click to expand...
ours should be a Type-B as on right
kR8wEB5.jpg


sorry .... yes it still has the generator.. and yes the ignition coil has been rewired to negative ground. Thanks you all. i will try flashing the system to see if that helps. one more thing......
on this three terminal VR do i need to remove the wire at the VR terminal or can i use a jumper wire to flash and leave the VR connected???
Click to expand...
 

Thanks JMOR. my generator has three terminals. one on the end and two on the side. i assume one of the side terminals is a ground that runs back into the harness. i need to look more closely and see if the case is stamped F for field and G for ground. is this still a type B system? all of the components look new. except the harness
 
(quoted from post at 17:02:52 07/26/20)
Thanks JMOR. my generator has three terminals. one on the end and two on the side. i assume one of the side terminals is a ground that runs back into the harness. i need to look more closely and see if the case is stamped F for field and G for ground. is this still a type B system? all of the components look new. except the harness
Click to expand...


i had some time this evening to check things out a little better. the system is definitely a type B. i have power to the Bat terminal on the VR with the Key off and Key on. the ground wire runs from the generator case back to the corner of the VR the big red wire runs from the ARM terminal on the VR to the big stud on the back of the Generator and the field wire runs from the FLD terminal on the VR to the field terminal on the generator. all wires are good and continuity is fine. even though i have voltage to the bat terminal all the time i DO NOT have voltage to the ARM terminal or wire. it is posible that the tractor was jumped with 12 volts at some time. do i have a faulty VR???
 
(quoted from post at 23:00:46 07/26/20)
(quoted from post at 17:02:52 07/26/20)
Thanks JMOR. my generator has three terminals. one on the end and two on the side. i assume one of the side terminals is a ground that runs back into the harness. i need to look more closely and see if the case is stamped F for field and G for ground. is this still a type B system? all of the components look new. except the harness
Click to expand...


i had some time this evening to check things out a little better. the system is definitely a type B. i have power to the Bat terminal on the VR with the Key off and Key on. the ground wire runs from the generator case back to the corner of the VR the big red wire runs from the ARM terminal on the VR to the big stud on the back of the Generator and the field wire runs from the FLD terminal on the VR to the field terminal on the generator. all wires are good and continuity is fine. even though i have voltage to the bat terminal all the time i DO NOT have voltage to the ARM terminal or wire. it is posible that the tractor was jumped with 12 volts at some time. do i have a faulty VR???
Click to expand...
he ARM & FLD will only have voltage when engine running & generator making sufficient output to pull the VR's cut out contacts closed, thus connecting ARM to BATT.
 

Thanks again JMOR. tomorrow i will see if the generator will motor. then i will jump the field to ground to see if i can get it to output. i am still on negative ground. do i need to return to positive ground??
 
(quoted from post at 23:43:23 07/26/20)
Thanks again JMOR. tomorrow i will see if the generator will motor. then i will jump the field to ground to see if i can get it to output. i am still on negative ground. do i need to return to positive ground??
Click to expand...
o, no, no...on a "B" type you DO NOT jump Fld to ground for max output.....you apply ARM voltage to FLD for max output.
 
(quoted from post at 20:57:24 07/26/20)
(quoted from post at 23:43:23 07/26/20)
Thanks again JMOR. tomorrow i will see if the generator will motor. then i will jump the field to ground to see if i can get it to output. i am still on negative ground. do i need to return to positive ground??
Click to expand...
o, no, no...on a "B" type you DO NOT jump Fld to ground for max output.....you apply ARM voltage to FLD for max output.
Click to expand...

Thanks JMOR........ will do. i will check back with results
 
(quoted from post at 05:39:11 07/27/20)
(quoted from post at 20:57:24 07/26/20)
(quoted from post at 23:43:23 07/26/20)
Thanks again JMOR. tomorrow i will see if the generator will motor. then i will jump the field to ground to see if i can get it to output. i am still on negative ground. do i need to return to positive ground??
Click to expand...
o, no, no...on a "B" type you DO NOT jump Fld to ground for max output.....you apply ARM voltage to FLD for max output.
Click to expand...

Thanks JMOR........ will do. i will check back with results
Click to expand...

UPDATE... i reconnected to positive ground and reconnected the ignition coil to positive ground. reflashed the generator and still no charge so i made a jumper to cross the batt terminal to the armature terminal at the VR and flashed it that way. now it is charging like new. Thanks for the help!!! a new question now i need a new bulb for the charge indicator.... anyone know what the bulb number is?????
 
(quoted from post at 12:50:37 07/27/20)
(quoted from post at 05:39:11 07/27/20)
(quoted from post at 20:57:24 07/26/20)
(quoted from post at 23:43:23 07/26/20)
Thanks again JMOR. tomorrow i will see if the generator will motor. then i will jump the field to ground to see if i can get it to output. i am still on negative ground. do i need to return to positive ground??
Click to expand...
o, no, no...on a "B" type you DO NOT jump Fld to ground for max output.....you apply ARM voltage to FLD for max output.
Click to expand...

Thanks JMOR........ will do. i will check back with results
Click to expand...

UPDATE... i reconnected to positive ground and reconnected the ignition coil to positive ground. reflashed the generator and still no charge so i made a jumper to cross the batt terminal to the armature terminal at the VR and flashed it that way. now it is charging like new. Thanks for the help!!! a new question now i need a new bulb for the charge indicator.... anyone know what the bulb number is?????
Click to expand...
lad you got it! Don't know a bulb number, sorry. Yes, Batt to ARM works on both Type-A and Type-B, but I seldom tell people that, because most of the world's people don't know that & only parrot what they have heard,...... I avoid a lot of flack!
 
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