100 amp alternator wiring

[plumsun3]

I'm adding a vintage a/c system along with aluminum radiator with electric twin fans on my '71 R/T. I added a 3 wire powermaster alternator but on startup the blue 18ga. field wire to resister starts smoking. Wiring is as was originally that was working fine. Do I need a larger gauge wire or some other upgrades to charging system? I have electronic distributor which was working fine before alternator change.

[Pete in NH]

Hi,

I took a quick look for a 100 amp 3wire Powermaster alternator for Chrysler products and didn't find anything. What model number Powermaster is it?

Something is not right and the blue wire which should be +12 volts from the ignition circuit should not be smoking. I don't think it's a matter of upgrading anything, something is not right, perhaps a defective alternator.

[John_Kunkel]

  Either the alternator has an internal short or the blue wire is touching ground somewhere between the regulator and the field terminal.

[plumsun3]

I was very careful about wiring especially connections that's why I was surprised. It's actually a 90amp. according to the Year One receipt. Didn't want to overdue it as only accessories added is the vintage a/c and fans for radiator. There is a lot of suggestions online just wasn't sure how to proceed. Original alternator should have been at 60amps and is has the factory 12 ga. power wire to gauge onto battery and 18ga. field wires which from I have read don't matter which installed improperly on terminals even though they are installed as on old unit. I'm now running a serpentine system that's obvious has aluminum bracketry which maybe a factor not mentioned anywhere.
Plan of action is to remove alternator and try to have tested. I may add separate power fused 8ga. lead directly to battery along with a ground wire back to battery as well. I have a feeling it could be in the alternator, maybe I'll end up just putting the old one back on.

[John_Kunkel]

Keep in mind that both '70 and later field terminals are totally insulated from ground, if you remove both wires and check the terminals with a meter, neither should show continuity to the alternator case.

[plumsun3]

Took new Powermaster alternator to have tested and found internal short. Smoked guys wires, he wasn't too happy even though I told him there maybe a problem.
Ordering a different one built through Quality Alternators, trust someone with more experience.

[John_Kunkel]

When running a "dual field" alternator on a spin-tester, one field terminal is grounded, so there's a 50-50 chance that a shorted field will test normal on a spin-tester. I always do the spin test with one field grounded and then swap the leads for a second test.