Re: One Wire 6 volt positive ground alternator

Posted by BigKev On 2015/8/25 16:47:06

I used a GM 10SI in my '54 Clipper which I converted to 12v. I went with a 3 wire version as I wanted to maintain my GEN light functionality. If you go with a 1 wire version, you would loose that if your car is equipped with a GEN light as opposed to AMP meter.

The purpose of the other wire, which is the "Voltage Sensing Wire", is to tell the regulator in the Alternator what the voltage is at the main harness junction so it can adjust output as needed.

A lot of folks simply bridge this to battery post, which works and is how single wire alternator are hooked up internally. But being bridged at that point is telling the internal regulator what the voltage is of the battery and not the voltage that is present at the main junction point after it gone through the resistance of the longer wire path, and possible multiple connection points. Hence why most auto makers use a 3 wire version, and hook the sensing wire to the main junction point (fusebox feed). That way the internal regulator is getting what the load voltage is on the harness as opposed to what the current battery voltage is. Which if you test with voltmeter without the alternator charging, you will see if probably different.

Just some food for thought.