Dual field alternator in single field vehicle

Electrical and Ignition

  1. dodgedartgt

    dodgedartgt Well-Known Member

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    Hi all,

    The front bearing in my alternator is starting to squeal. The '67 'cuda is wired for single field alternator. I can only find a dual field replacement from the common sources. I have to have the car driving before Sunday.

    What modification do I need to make to use a dual field alternator?

    The replacement I bought has two terminals labeled FLD. One looks like a normal spade connector, but the other does not look the same.

    What do I do?

    Thnx, Mike in FL
     
  2. 70aarcuda

    70aarcuda Master Hoader of SBM FABO Gold Member

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    you need to get the 1970 and newer voltage regulator...and add the second field wire...

    looking for a diagram on line...or do a search on google

    it is not rocket science
     

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  3. 70aarcuda

    70aarcuda Master Hoader of SBM FABO Gold Member

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  4. abodyjoe

    abodyjoe Well-Known Member

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    for a temp fix you can ground one of the fld terminals on the alt and it will work.. :)
     
  5. abodyjoe

    abodyjoe Well-Known Member

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    [​IMG]
     
  6. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    Nothing temporary about it. Most the replacement 69/ earlier regulators are already electronic, so if you have a good one that works, there's nothing at all wrong with grounding one field terminal, and using the old style regulator.

    If you don't care about "resto looks" you can use a squareback which is a superior design.
     
  7. dodgedartgt

    dodgedartgt Well-Known Member

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    The car has been in hibernation for some number of yrs before the 16 yrs I've owned it. It doesn't have an electronic regulator, still has the old mechanical style points voltage regulator.

    Abdyjoe - Which terminal should be connected to ground? Nearest, or furthest from the main power stud? I don't want to toast a $56 alternator, much less the wiring or any other components when installing this.

    Thnx, Mike in FL
     
  8. abodyjoe

    abodyjoe Well-Known Member

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    it doesn't matter if i remember correctly.
     
  9. KitCarlson

    KitCarlson Well-Known Member

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    Field polarity does not matter on the isolated field alternators.

    The field energizes the electromagnetic rotor. The rotor has interlocking end plates that form magnetic poles. The curved lobes bent on the plates alternate N-S-N-S.... on the rotor circumference. Polatity does not matter, AC is always generated in the three stator windings, and full wave rectified by 6 diodes.
     
  10. skykeith

    skykeith Well-Known Member

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    If the alternator you bought doesn't have two identical spade connectors, the terminal without the spade is probably already grounded. Check the resistance between the spade terminal and alternator case. If the resistance is 10 to 20 ohms, it's already grounded. If there is no resistance, just take the screw out of the terminal with no spade lug, remove the insulating washers and put the screw back in, then connect your regulator to the spade terminal.
     
  11. jimjimjimmy

    jimjimjimmy lobsterman FABO Gold Member

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    thanks abody joe that's about as simple of a diagram one could get my 5 year old son could hook this up .
     
  12. itate

    itate Where is that wrench I just had in my hand?

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    Is this what yours looks like? The rounded off terminal is grounded to the case. I have this on my Barracuda and it works a lot better at idle than a roundback.
    [​IMG]
     
  13. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    I didn't even know anyone was selling something like that. Where did you get it, and do you have a part no? I'm suprised they didn't just make a cheap jumper and throw it in the box, so they could sell it for "all" years.
     
  14. dodgedartgt

    dodgedartgt Well-Known Member

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    Thanks for everyone's input.

    Itate, exactly same as what I've got. The 2nd spade terminal doesn't look "normal".

    Skykeith, I'm headed to a friend's house to borrow a VOM meter. I expect it is exactly same as you say. Will report back.

    Abdyjoe and 70aarcuda, thanks for the links and drawings. I'll be saving those for future upgrades. Right now, I just need to get the car home. I'll try to find an electronic early style regulator to install for this drive before I leave.

    Mike in FL
     
  15. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    What makes you think you need one?
     
  16. itate

    itate Where is that wrench I just had in my hand?

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    Napa,
    RAY 131001 35 amp single pulley.
    RAY 132003 60 amp dual pulley.
    I have the 35 amp and when I got it I looked in the box and was surprised to see a squareback.

    Autozone has an electronic regulator for the pre-1970 wiring, part number VR706
     
  17. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    Thanks for the info. Just about every 69/ earlier regulator you buy is now electronic. Easy to ID. Look underneath. If there is NOT two large wirewound resistors, it's an electronic regulator. Not all electronic ones have the short stubby case
     
  18. itate

    itate Where is that wrench I just had in my hand?

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    Thanks, that's good to know. I've heard of them but never seen one.
     
  19. seabee

    seabee FABO Gold Member FABO Gold Member

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    Thanks for the thread. Before I start her up tomorrow can anyone verify this photo as correct?
    [​IMG]
     
  20. KitCarlson

    KitCarlson Well-Known Member

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    The alternator output wire looks undersized. It looks like it has been hot enough to burn the insulation, and has been repaired with heat shrink. Best to use at least 6 gauge

    Your wiring seems to be for early regulator, If you attempt to use late model regulator, without wiring per schematics above, it will not work.
     
  21. seabee

    seabee FABO Gold Member FABO Gold Member

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    Thanks,

    I am using the early style regulator (single field).
     
  22. 5.7 hemi

    5.7 hemi FABO Gold Member FABO Gold Member

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    That alt. in the picture above is a dual field, and is wired correctly.
     
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    • Ironracer

      Ironracer Gearhead

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      I was changing alt belts Andy alt broke. I have a old alt that was on my 66 satellite with the points reg. Can I put it on a 74 duster?
       
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