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Alternator questions

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Sample, Jun 21, 2003.

  1. Sample

    Sample 1/2 ton status

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    My alternator has stopped working completely. It is the 94 amp model on my '83 with a 350. Thus far I have replaced the brushes and the voltage regulator with no luck. What else should be changed? What is the next most likely culprit?

    Thanks,
    Chris
     
  2. BobK

    BobK 1/2 ton status

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    A CS130 or the 10SI or 12SI model?
    The CS130's are notorious for overheating and dieing.
    Poor design of the case(poor ventalation).
    On the SI series it's usually the diode trio that goes.
    Are the 3 wires coming off the stator intact?
    The SI series of alt's is what's prob. in your truck.Go to any auto electric store and get yourself a rebuild kit.It should come with a front bearing,diode trio,brushes and springs and possibly a rectfier bridge but I'm not sure on that last one.
    Here's a link to the process if your not familier with it.
    http://www.gnttype.org/techarea/electrical/alt.html

    here too
    http://batee.com/corvette/dcrg/readerstips/larsstuff/this_tech_paper_will_discuss_sim.htm
     
  3. Sample

    Sample 1/2 ton status

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    Just went and got a remanufactured alternator. Still no luck. Can a completely dead battery cause the alternator to not charge while the engine is running? In theory, you should be able to disconnect the battery once the motor is running and the alternator will keep it going.

    What do the three wire from the alt. run to?
     
  4. BobK

    BobK 1/2 ton status

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    Here is paragraph from M.A.D. Enterprises site
    http://www.madelectrical.com/index.shtml


    How the THREE-WIRE Voltage Regulator Works
    (the Turn ON & Warning Light circuit)

    With the “THREE-WIRE” alternator model built for cars and trucks, one of the voltage regulator terminals is wired to an ignition switched OFF/ON source. And the OFF/ON circuit may also be used to operate a warning light at the dash. (The THREE-WIRE type can be wired with or without a warning light at the dash. The warning light is an option–not a requirement.)

    REMOTE VOLTAGE SENSING, a THREE-WIRE advantage
    The other of the two plug-in wires at the SI series alternator is the “voltage-sensing” terminal for the voltage regulator. Through the sensing-wire, the voltage regulator monitors electrical system voltage and makes adjustments to alternator output. The regulator will adjust alternator output as needed to maintain the place where the sensing-wire is routed (at about 14.2 volts). And the sensing-wire can be routed to a place remote from the alternator (downstream).

    This “remote voltage-sensing” feature is often a big advantage when running with a factory type wire harness from the Muscle car period (60’s and early 70’s period cars and trucks). Then the alternator output will be adjusted according to what goes on far downstream from the alternator–at the main power distribution junction, which operates the whole car plus charges the battery!
     
  5. bigblock44k5

    bigblock44k5 1/2 ton status

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    Depends how you start it. i once fried a battery cable on the trail and tried to get a pull start with no battery at all and it wouldn't fire up. if someone is giving you a jump start, the alternater should take over as soon as the engine cranks up. you need to have voltage going in to the alternator for the field current to "jump start" the alternator on, after that it will charge with or without a battery. make sure you have voltage going into the alternator. im not sure what wire setup you have on that alternator, but it will be one of the smaller wires, or all of them.
     
  6. imiceman44

    imiceman44 1 ton status

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    [ QUOTE ]
    Depends how you start it. i once fried a battery cable on the trail and tried to get a pull start with no battery at all and it wouldn't fire up. if someone is giving you a jump start, the alternater should take over as soon as the engine cranks up. you need to have voltage going in to the alternator for the field current to "jump start" the alternator on, after that it will charge with or without a battery. make sure you have voltage going into the alternator. im not sure what wire setup you have on that alternator, but it will be one of the smaller wires, or all of them.

    [/ QUOTE ]

    Exactly, it will need a jump start to start charging, that is why you should have good power in a battery to start charging.
    I learned that the hard way.
     

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