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Whats goin on with this freakin alternater?

Discussion in 'The Hokey Ass Message Board' started by flthd, May 22, 2011.

  1. flthd
    Joined: Sep 13, 2010
    Posts: 169

    flthd
    Member

    I cant get my alternator to put out! Its a three wire and I have 12v exciter goin to one with 12v then two jumps to the terminal on the back.Its a new harnes and I tried two alternators still .62 volts:confused:
     
  2. Mr48chev
    Joined: Dec 28, 2007
    Posts: 30,202

    Mr48chev
    Member

    Just out of curiosity do the connections for the wires go like this I I or like this - -.

    Or do you have a photo of the alternator showing the plugs?
    The units with the plugs I I are external regulator units while the ones with the plugs going - - are internal regulator.

    I've done several using a diagram similar to this one.
     

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  3. flthd
    Joined: Sep 13, 2010
    Posts: 169

    flthd
    Member

    Yea its the internal regulated one.This really has me stumped.I think this has been my whole problem for awhile now.Your diagram is how I have her wired.Maybe somehting to do with the exciter wire voltage.
     
  4. sounds stupid, but make sure the case is grounded.

    Had nice powdercoated brackets insulate the case and cause low or no output volts.

    As a rule, I always run a 10 gauge ground lead from the back case lug to a known good ground.
     

  5. flthd
    Joined: Sep 13, 2010
    Posts: 169

    flthd
    Member

    Yea its grounded then I was just tryin it out got real hot and started stinkin I shut her down.Right before that my volt meter read -13v at the terminal on the back of it.
     
  6. flthd
    Joined: Sep 13, 2010
    Posts: 169

    flthd
    Member

    Pretty straight up thing.
     

    Attached Files:

  7. You can connect the number two wire to the positive as you show or you can hook it to an ignition source as GM did originally. This can prevent the alt from causing a drain. The number one wire does need to be connected to a positive + voltage connection also. If either 1 or 2 is grounded, the regulator shorts out.

    If I read your post correctly, you stated -13V, Negative voltage? If so, the diode trio is probably toast.
     
  8. flthd
    Joined: Sep 13, 2010
    Posts: 169

    flthd
    Member

    Yea it said neg. right off the get go.That kinda threw me off.Now the other new alternator was puttin out.62.When I flipped the wires on the one I just smoked it read +12.5.weird
     
  9. Willy301
    Joined: Nov 16, 2007
    Posts: 1,426

    Willy301
    Member

    Not sure, but I am running this same alternator on my firetruck, when it stopped charging I took it to my rebuilder and he shorted two of the wires across one another to repolarize the magnets or some such thing. It immediately corrected the problem and it works better than ever now.
     
  10. flthd
    Joined: Sep 13, 2010
    Posts: 169

    flthd
    Member

    All right did a little more check and my block has voltage 2v only when its runnin.Somthing is short out somwhere.
     
  11. Jerryinok
    Joined: Mar 10, 2008
    Posts: 38

    Jerryinok
    Member
    from Oklahoma

    With the engine not running do you have 12+ volts on the big lug and with the key on do you have voltage on the #1 wire on the plug? If you were getting a negative - reading, you didnt have your meter wires swapped did you? If all checks out it sounds like a bad alt.
     
  12. flthd
    Joined: Sep 13, 2010
    Posts: 169

    flthd
    Member

    I had the solinoid wires crossed,I put a one wire alt. on and its chargin proper.Now with alternator hook up the car runs terrible I cut the wire going back to batt. and it runs fine:confused::confused:
     
  13. Jerryinok
    Joined: Mar 10, 2008
    Posts: 38

    Jerryinok
    Member
    from Oklahoma

    Where are you hooking the output wire from the alt to?What type of ignition are you using?points or Hei?Was wondering how the 14 volts the alt was putting out could effect the ign. unless your running points and no resister.
     
  14. need louvers ?
    Joined: Nov 20, 2008
    Posts: 12,906

    need louvers ?
    Member


    triodes?!?!
     
  15. johnny bondo
    Joined: Aug 20, 2005
    Posts: 1,547

    johnny bondo
    Member
    from illinois

    i see you have the one wire coming from the battery wire. i always heard you arent supposed to do that because it drains the battery and can back feed the system. try putting the exciter wire on the "acc" on the ignition. also, you might want to put the battery wire through a relay with an "acc" switched leg.
     
  16. no the #2 terminal goes to the battery lug on the back of the alt, the #1 terminal goes to a diode or warning light which keeps the system from backfeeding. Always use a MIN of a 10 gauge wire for the battery feed to the alt.


    make sure the alt case is grounded (empty bolt hole on the back) to the battery and the motor is grounded to the frame GOOD.
    I would recheck your #1 wire and grounds.

    another post about the #1 wire
     
  17. Mr48chev
    Joined: Dec 28, 2007
    Posts: 30,202

    Mr48chev
    Member

    You do that with a generator but it will blow the diodes out of an alternator. Pure nonsense there.
     
  18. Mr48chev
    Joined: Dec 28, 2007
    Posts: 30,202

    Mr48chev
    Member

    Yep it's known by diode trio or tridiode and probably some local names in some areas.
    [​IMG]

    Flthd if you pull the alternator apart you can check the tri diodes by clipping one ohm meter lead to the single leg and touching each of the three legs with the other lead. then reverse the leads and do it again. You should have continuity on all three legs one way and not have it the other.
    Then you need to check the diodes in the rectifier bridge aka diode bridge,

    You also want to make sure that The brushes are in good shape and not worn down too far.

    This link is actually for converting an alternator to one wire but it is real good for step by step instructions for taking one apart and putting it back together http://www.dacoglu.com/DesotoCD/6_Electrical_System/OneWireAlternator.htm






































    .
     
  19. flthd
    Joined: Sep 13, 2010
    Posts: 169

    flthd
    Member

    Man all the suggestions are great! Well I put the solinoid wires on backwards coupled with the fact that I pretty sure the remaned alt might have been defective she's chargin now.But most importantly she'll charge and run!!!! Turns out I had to run two ballast resisters in a row to my coil.My freind called mallory and they told him about having 3ohm resistance soo here I am with a great runnin flattie. :D
     
  20. need louvers ?
    Joined: Nov 20, 2008
    Posts: 12,906

    need louvers ?
    Member

    Thanks Mr48Chev,
    The info is appreciated, but I have to admit that "TRIODES" is an inside joke with ElPolacko and myself. Much like shoe horn or grommlets... Crap, now I might have to explain those!
     
  21. flthd
    Joined: Sep 13, 2010
    Posts: 169

    flthd
    Member

    Ha ha its all good man.Im just so happy my cars runnin right finally.
     
  22. Engine man
    Joined: Jan 30, 2011
    Posts: 3,480

    Engine man
    Member
    from Wisconsin

    There is a tab on the regulator that can be grounded through a D shaped hole to full field it. It sometimes needs to be done when an alternator is rebuilt on it's first run. Rebuilders usually test run them and would do it if it doesn't fire. I've had 2 do it in 45 years.
     

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