Looking at the specs on the D series Allis tractors, it says that some (or all) of them are a positive ground. I know a lot about electrical stuff, but this has me puzzled. First off, WHY would they wire it that way? Negative ground is just the norm. If they may have made some very old cars with POS ground, I have not heard of it. Every car and truck I have ever owned has had a NEG ground.
When I think what's connected, most of the stuff should not matter. Light bulbs wont matter, and neither will a horn. Yes, electronics, such as a car radio would not work, but that's not a common item on an older tractor. An electronic ignition, WOULD matter, but for a system with Points, that should not matter
For an older tractor, all that remains, is the Starter and Generator or Alternator.
This is where I get puzzled. Will a starter run backwards if the battery polarity is reversed? I really dont know, for a brush motor, which seems to be the type of motor used on tractors (and I think all vehicles)?????
That leaves the generator and I know those older D series Allis tractors had generators, not alternators. It's been at least 40 years since I last worked on a car with a generator, so I'm fuzzy on the circuitry. I only recall the voltage regulators had 3 wire terminals and were a pain to trace and repair if they failed. So, whether the polarity matters, I can only guess, and my guess would probably be answered with a YES. (just a guess).
Besides wanting to better understand this, I'm also trying to learn what would happen if I wanted to get rid of the generator and replace it with a modern alternator. For example, my Farmall M, came from the factory with a generator and a 6 volt battery. was it a POS or NEG ground originally? I dont know? But now it's a NEG ground, and I've worked on several other Farmalls (M and H) and all of them have been converted to 12V with a modern alternator with the regulator built into it. (GM type).
So, lets say I was to buy an Allis D series with a generator, and wanted to replace the generator with a modern alternator.
As I said earlier, the lights will work fine, and if the ignition has points, it too should work. I have never heard of an alternator with a POS housing. All of them are NEG ground, and the housing is part of the circuit, so it would have to be a NEG grounded system, in order to use an alternator.
This just leaves the starter. If it runs backwards with the polarity reversed, that's a big problem. If not, I cant see how the polarity would matter. Once a modern alternator was installed, the tractor would become NEG ground.
Feedback appreciated!
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By the way, I was talking to someone about this, and the guy insisted that when a tractor has POS ground, you put the red clip from a battery charger on the NEG battery terminal and the black clip on the POS terminal. I told him NO NO NO..... That's not going to work. But he insisted he's right, even though I know he's wrong and all he will do is ruin his battery charger if it dont have built in protection.
Thanks
When I think what's connected, most of the stuff should not matter. Light bulbs wont matter, and neither will a horn. Yes, electronics, such as a car radio would not work, but that's not a common item on an older tractor. An electronic ignition, WOULD matter, but for a system with Points, that should not matter
For an older tractor, all that remains, is the Starter and Generator or Alternator.
This is where I get puzzled. Will a starter run backwards if the battery polarity is reversed? I really dont know, for a brush motor, which seems to be the type of motor used on tractors (and I think all vehicles)?????
That leaves the generator and I know those older D series Allis tractors had generators, not alternators. It's been at least 40 years since I last worked on a car with a generator, so I'm fuzzy on the circuitry. I only recall the voltage regulators had 3 wire terminals and were a pain to trace and repair if they failed. So, whether the polarity matters, I can only guess, and my guess would probably be answered with a YES. (just a guess).
Besides wanting to better understand this, I'm also trying to learn what would happen if I wanted to get rid of the generator and replace it with a modern alternator. For example, my Farmall M, came from the factory with a generator and a 6 volt battery. was it a POS or NEG ground originally? I dont know? But now it's a NEG ground, and I've worked on several other Farmalls (M and H) and all of them have been converted to 12V with a modern alternator with the regulator built into it. (GM type).
So, lets say I was to buy an Allis D series with a generator, and wanted to replace the generator with a modern alternator.
As I said earlier, the lights will work fine, and if the ignition has points, it too should work. I have never heard of an alternator with a POS housing. All of them are NEG ground, and the housing is part of the circuit, so it would have to be a NEG grounded system, in order to use an alternator.
This just leaves the starter. If it runs backwards with the polarity reversed, that's a big problem. If not, I cant see how the polarity would matter. Once a modern alternator was installed, the tractor would become NEG ground.
Feedback appreciated!
---------
By the way, I was talking to someone about this, and the guy insisted that when a tractor has POS ground, you put the red clip from a battery charger on the NEG battery terminal and the black clip on the POS terminal. I told him NO NO NO..... That's not going to work. But he insisted he's right, even though I know he's wrong and all he will do is ruin his battery charger if it dont have built in protection.
Thanks