positive and negative ground

alfrehner

Member
Ok so I admit I am a bit of an electrical dummy. Can someone please explain to me what is the difference in the positive and negative grounds? I am working on a 49 A and bought an electronic ignition, but I got the negative ground, and it is supposed to be a positive ground, I think. I got this tractor in pieces and have been slowly putting it back together for a friend, and I was wondering if I can just swap it around? Thanks
 

Difference in positive or negative ground is the way the electricity flows but either way the voltage is the same. If it was my tractor I'd attach battery negative ground,install electronic ignition & polarize generator if applicable then call it done.
 
I agree. Make it negative ground so its ready for an alternator instead of the generator, if the time comes.
 

Also after you polarize the generator make sure you have the correct regulator, swap the wires around on your ammeter and coil.
 
Even though the tractor was originally POS Ground, since you already bought a NEG ground elec switch, I would change the tractor over to NEG ground. Be sure to Polarize the genny BEFORE start up,,,,,,,,Insure the VR is suitable for NEG ground,,,,,Swap the ammeter leads so it doesn't read bass ackwards, and the coil will be wired so the - gets switched to ground via the elec ignition unit and the + gets power from the ignition switch.

John T
 
You are dealing with an "A" circuit generator.

Polarizing is done by momentarily connecting power from the ungrounded side of the battery to the "A" (ARM) terminal of the generator.

This is commonly done by momentarily jumpering the "A" and "BAT" terminals at the voltage regulator or cutout BEFORE initial startup of the engine after major electrical repairs.

If dealing a totally different charging system with a "B" circuit generator the procedure is different, DO NOT use the "A" circuit procedure.
 
Polarize by using a jumper wire and momentarily jumping from [b:654c4848f0]BAT[/b:654c4848f0] terminal on the voltage regulator over to [b:654c4848f0]ARM[/b:654c4848f0] (armature) terminal to get a small spark.

Take a look at the photo below.

a261809.jpg" width="650"


Hope this helps.
 
In line with the good advice below, note you should get a "spark" when you make that momentary connection. Do that BEFORE you start the tractor. The genny can work at EITHER Pos or Neg ground, just polarize FIRST like the good gents told you...

John T
 

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