3 wire alt hookup

[J-440]

 Have a Powermaster 140 amp alternator that is not charging the battery.  It was a 1 wire alternator but now I'm converting it to the 3 wire alt.  I have the harness that plugs into the back of the alt, but need a diagram as to where the wires go.  The larger red from the harness goes to the terminal on the alt that goes to the battery, but where do the smaller black and brown wires go to?  Thanks again.

[Pete in NH]

Hi,

The 1 wire alternator had an internal voltage regulator. A 3 wire alternator implies an external voltage regulator. I'm not sure what you're working on as the wire colors you mentioned do not match any late 60's-early 70's Mopar color codes. I'm going to need more information to understand what you are trying to do. What alternator and regulator are you trying to wire up? What car are you working on and what wiring harness is in it? Also. just because the battery is not charging does not always mean a bad alternator/regulator.

The brown and black wires are most likely fields wires to the alternator but don't match the color codes I would expect.

[J-440]

 Ok I'm also using a MSD 6AL box and a FAST distributor so there is no ballast resisitor or voltage regulator.  1 terminal is the 4 gauge wire going to a mini starter, 1 terminal is grounded to the frame. I pull the boot off and there are 3 pins.  I have the mini harness that plugs into those pins.  On the mini harness is a 8 gauge red, 10 gauge black and 10 gauge brown.  Where do the brown and black go to?

[Pete in NH]

Exactly what Powermaster alternator are you using? There should be a model number.

[J-440]

 Ok Pete new question. I've figured out where the wires go.  Red to the battery, brown to a idiot light on the dash, and the black is for an ignition hot source.  I have the stock engine harness (passenger side of motor).  Since I'm not using any of the wires that connect the ballast resisitor or the voltage regulator, can I connect the black wire from the alternator to the green wire that would have gone to one side of the voltage regulator?  That green is ignition hot/run only correct?

[John_Kunkel]

The green field wire on the alternator was originally the variable ground supplied by the VR, the blue field wire on the alternator is keyed 12V.

[J-440]

 Sweet, then I'll just wire it to the blue.  Thanks John.

  Was just informed that this alternator has an internal regulator but it needed an external power source which is why I'm using this mini harness.  The guys at Powermaster said that the 1 wire would be ok.  So much for their tech help.  My ECM was spazzing out bc the alternator wasn't putting out enough voltage.