Ford 3G alternator rectifier upgrade

[brianl703]

I've read that all it takes to upgrade a 130-amp Ford 3G alternator to 160 amps is an upgraded rectifier. The stator coil does not need to be changed.

Does anyone know if that's true? If so, why? Is the upgraded rectifier causing less voltage drop so you get another 30 amps of output?

 

[meep]

I don't buy it. I would think it's rectifier AND the outer coil. The stator coil is the field coil I believe, so I don't think it would be effective--- it makes the magnetic field-- it's the outer coil that has to be upgraded to handle higher current. BUT-- I'm not well-acquainted with the Ford alts...

M

 

[brianl703]

The stator is the outer coil. I've read that the rectifier is all that needs to be upgraded for higher output in several different places. Apparently the one I want has avalanche diodes.

 

[jmac]

From what I've read, the 3G rated at 130A will normally put out a peak of 150-160A when tested. This gives a nice amount of cushion between rated output and 100% output, as its better for longevity to not run at 100% much of the time. This is why they say you don't have to change out the stator.
There are diode upgrades to make the unit more reliable sold aftermarket with double and triple output diodes, and HD avalanche diodes, along with beefier external regulators and upgraded connectors if it has the 3 prong spade type, but I doubt they increase peak output more than an amp or two. I read the 130A stator was purple and the lower 95-110A one was yellow I think, and there is a 200A version, don't know what color it is. Then you have to differentiate between large case and small case 3G's as well.

 

[meep]

ugh--- i hate getting things backwards--- I recall the first time I opened it up-- worked backwards from the typical DC motor where the field is on the outside.

If the stator is overspec'ed by design, then yes, diodes will help; it'll just run hot as that copper passes all that current.

Do you need the extra juice? Might be pretty reasonable to have a local shop re-wind the stator for you, or sell you the upgraded stator. By the time you get to the diodes, you've cracked the whole thing open.... 200 amp would be a nice upgrade AND more efficient (less waste in heat).

M

 

[brianl703]

I've already cracked the alternator in question open to reclock it. After seeing how easy it would be to replace the rectifier, that's when I started looking into what it would take to get more output.

I don't need the extra juice; however, in the process of disconnecting it when removing it from the vehicle, I broke the locking tab off the stator connector inside the alternator so the rectifier will need to be replaced to fix that. The connection stays for now, but I'd rather not be driving it and hit a bump and have it come loose.