2- Field Wire Alternator: Blue/Green wire hookup

[Demonx2]

Simple question for you alternator gurus out there...I've searched through many old posts on the topic but don't seem to find the answer to my question. Working on my 71 Demon 340 and installing a new Evans main engine wiring harness. The car has electronic ignition with the blue VR as shown in the pic.

Here's the question: on the 2 field terminal alternator, does it matter which terminal gets attached to the blue or green wire that comes from the VR? (Blue wire goes to middle/upper post on VR and green wire to the right/lower post.)

The FSM shows these wires attaching to the Field terminals but does not decipher between the terminal closest to the output post or the one farther away. I don't think it matters which wire goes where but would rather have an expert confirm that!

Below is a pic of the alternator and the VR. (And yes, the VR is grounded to the sheetmetal as I get continuity from the case to the alternator body.)

Thx for the help!! I'd rather not fry something due to my stupidity so thought it best to ask.

 

[moparmarks]

Either terminal is fine

 

[Dana67Dart]

Doesn't matter.

It is an "isolated field" alternator.

 

[Demonx2]

Thank you fellas. I appreciate your expertise and willingness to share it!

 

[67Dart273]

MAKE ABSOLUTELY CERTAIN you inspect the brush holders and insulating hardware for "weak" or damage, and electrically check with an ohmeter. BOTH terminals should be open (infinity) to the case

 

[oldkimmer]

I always put the blue to the top and the green on the side as that’s how the factory did it. Kim

 

[moparmarks]

I always put the blue to the top and the green on the side as that’s how the factory did it. Kim

Agree but it will still charge just the same when reversed.

 

[Mattax]

This photo I posted in Identify Chrysler Alternators comes from Scott Smith Harms

Saw this bad boy on a car at Russo Steele over the weekend, don't see many like this one installed on cars there days, it's thre real deal, probably NOS when installed on the car (1970 440+6 Challenger).

its on a bigblock so the photo is probably rotated a bit. Note the wrapped harness supported on the alternator goes to the right front fender area.

 

[Demonx2]

MAKE ABSOLUTELY CERTAIN you inspect the brush holders and insulating hardware for "weak" or damage, and electrically check with an ohmeter. BOTH terminals should be open (infinity) to the case

Yep, checked and confirmed. Thx for that tip too!

 

[Demonx2]

I always put the blue to the top and the green on the side as that’s how the factory did it. Kim

Good idea - thx!

 

[oldkimmer]

Agree but it will still charge just the same when reversed.

Yes it will charge either way. I still want it the way the factory did it. Kim

 

[moparmarks]

Yep actually a lot of time the green wire is a bit longer than the blue one. Blue one won't reach the lower terminal when routed correctly.

 

[67Dart273]

When you look at a rotor, you can see the "fingers" of the end cores which wraps around the edges. the rotor is a simple solenoid coil electromagnet, and the "fingers" wrapped around from each end form the north/ south poles which alternate. Of course when turned, the engine adds the power, the rotor moves and you have a "moving alternating electric field." The blue wire provides full battery power to either end, and the green VR wire controls "the amount of ground return" IE the amount of current flowing in the rotor. More rotor current, = more alternator output. The VOLTAGE the alternator outputs is dependent on the load on the system, and the VR senses that voltage and constantly adjusts rotor current to keep the output voltage correct. The VR MUST be grounded exactly to battery ground potential, and the VR IGN terminal MUST be exactly same potential (no voltage drop) to the battery positive.