gm alt mod question

countryguy53

countryguy53

Daily Driver
i bought a new alt (the 63amp one 3oclock position) since the alt has two spade connectors on it and the origional has one which one do i hook it to? I know that if i tie the two spades together it starts putting out 12v. this is how my tractor gets a charge. I haven't installed the new one yet but just don't want to mess up something. so do i short the two and let it put out happen or will the lead from the old alt regulate the output? So which spade connector should i connect to or short them together? Gene
 
GM alternators commonly have a "field" connection and a "sense" connection (in addition to the main output stud and chassis ground). Google "GM alternator field sense". The thin wire that was connected to the original alternator needs to go the the "field" connection on the new GM alternator. The sense connection can be connected to the main output stud and it will work fine. Do not connect it to the "field" wire. The original alternator had an internal voltage regulator that regulated the voltage to 14 V at the main output terminal. The GM alternator has a voltage regulator that regulates to 14 V (or is it 14.5 V?) at wherever you connect the "sense" wire. So, if you wanted to get fancy you could run a wire from the "sense" terminal and connect it directly to the battery terminal. Now the regulator would regulate the voltage at the battery, compensating for any loss in the fat cable between the alternator to the battery. I would not bother, though. I'd just connect the "sense" directly to the alternator output.
 
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thanks for the info

i read your post and went out and got the new alt, its only markings near the spade lugs are 1&2. I read thru all the paperwork with the new unit and it doesn't tell which is Field or Sense. Do you know which is the field? I hate to be dumb about this but its easier to ask now than fry something... Gene
 
Here is the link and photos...

... to a GM conversion.

I added an update at the bottom, but wired it exactly as Tom shows us in his fotos. Works PERFECTLY!
 
ive tried this twice and i wasnt happy with either attempt, i could not get the pulley's lined up causing belts to snap, and would not charge properly when the belt got wet, but hey, if you can pull it off, great, if not, stay with stuff that fits...

perhaps i just need a good bracket
 
excellent, thanks

I'll get the bracket and finish it tomorrow. it will be nice to have it hooked up right the first time, i hated the idea of doing it blind and with my luck it would be wrong...Thanks again Gene
 
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