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Generator Pulley Size

Discussion in 'Early CJ5 and CJ6 Tech' started by Jrobz23, Dec 12, 2016.

  1. Dec 12, 2016
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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  2. Dec 13, 2016
    Rick Whitson

    Rick Whitson Detroit Area 2024 Sponsor 2022 Sponsor

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    I have a generator from a jump starter from a Tow Truck, before computers were on cars they would jump start them with high output generators. A friend gave me his, it had two high output generators on it with a seven horse B and S motor on it. I put it on my Jeep, It would not charge until I was at a higher RPM, I assumed it was rewound for high output. You can have it for shipping if you want it, it is like new condition, and I think I still have both of them. PM me if you want it.
     
  3. Dec 13, 2016
    Jrobz23

    Jrobz23 Member

    Northern, WI
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    Little more about the use case. The Jeep is 6v still but debating a switch to 12v for a few unrelated reasons. It rarely sees 10 MPH let alone 50, so max speed right now isn't really relevant to this Jeep. It is used more like a tractor, to Termin8ted's point. The reason I stated the 3K RPM comment was due to the fact that the pulley on the generator would have been sized for 4K RPM upper bound, which for my use case is a complete waste. Hell, this Jeep doesn't see 2K RPMs with any regularity, and certainly does not sustain that when it does hit it. If I can size the pulley to effectively charge more from 800 RPMs to 3200 RPMs that is a net win all around, for me.

    Howard, I'll check into the Volts at 1200.

    Rick, I appreciate the offer. Lemme tinker around with what's on it first. If it comes to it, I may snag that from ya.

    Thanks all for the feedback! I do appreciate it.
     
  4. Dec 13, 2016
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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  5. Dec 13, 2016
    termin8ed

    termin8ed I didn't do it Staff Member

    Mason, MI
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    There is some good info there, but yea, brushes lift up due to centrifical force?
     
  6. Dec 13, 2016
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Yeah. I think 'bounce' might be more accurate.

    courtesy-twitter.com_-300x195.jpg
     
  7. Dec 14, 2016
    Rick Whitson

    Rick Whitson Detroit Area 2024 Sponsor 2022 Sponsor

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    Ditto Howard and PeteL ,
     
  8. Dec 15, 2016
    wasillashack

    wasillashack Member

    Wasilla, Alaska
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    An easy way to determine if the brushes are bouncing is remove the metal band around the generator that covers the brushes, start the engine and watch for sparks or lots of movement if the brushes. A little sparking is normal, brush movement is not. A REALLY rough commutator is about the only way this can occur, I suppose an extremely weak brush spring could allow this to happen, but I've never seen it. If that is the problem, it can be cheaply repaired.
    I live in Alaska and charging problems with plow trucks is an everyday occurrence here, even with HO alternators. You are asking your vehicle to do something it is not equipped to do.
    Some will disagree, but in my experience, 6 and 12 volt generator systems are problematic, UNLESS IN PERFECT CONDITION. Also, the so called one wire alternators are great when they work, but you most likely not find rebuild/repair parts for them at your local parts store, if at all. Rebuilding generators and alternators at home is a dying art, it is hard to find any more than brushes, regulators, bearings and diode bridges at any parts store, if at all.
    HTH, Good luck!
     
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  9. Dec 15, 2016
    eti engineer

    eti engineer Member

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    Suggested idle speed for an F-134 is 900 rpm, which is close to 20% of redline. I have an alternator on mine and it will keep the voltage good at idle with all electrical loads turned on and I have mine idling at 700 rpm. I would think that a generator would do a good job at 900. The regulator can be adjusted to make the generator charge at this speed, but only to a certain extent. Make sure to turn the correct adjustment. If you adjust the cut-out relay to a point where when it is de-energized the spring doesn't pull it off the contacts, the battery stays connected to the gen and it will try to use your generator as a starter to turn over the engine. Eventually, something is going up in smoke, and it is usually the generator...
     
    Last edited: Dec 24, 2016
  10. Dec 16, 2016
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    ? My FSM shows idle speed to be 600 rpm, not 900.

    I think a generator ought to function well enough under nearly all conditions - they always have.

    In any case there is no logic in trying a lot of extreme ideas until the most simple basics are verified - is the battery good, are the brushes and commutator clean, connections tight, belt tensioned, etc.
     
  11. Dec 16, 2016
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Yeah, I was wondering where he got 900 from.
     
  12. Dec 16, 2016
    eti engineer

    eti engineer Member

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    Straight out of an FSM. I will see if I can find it again.
     
  13. Dec 20, 2016
    Jrobz23

    Jrobz23 Member

    Northern, WI
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    Update: I have a vacuum leak in the propane intake adapter.. no voltage testing yet. Bigger fish to fry lol.
     
    Last edited: Dec 20, 2016
  14. Dec 22, 2016
    1960willyscj5

    1960willyscj5 Well-Known Member

    Mesa, Arizona
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    Same place I did. My engine prefers a grand for idle. is not happy at all below 950 rpm and no way will it do 600 rpm
    Could be because the flywheel doesn't weigh a bunch. Don't know, haven't had to remove the flywheel.
     
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  15. Dec 22, 2016
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    All I have ever seen in manuals is 600 rpm, and 650 to 700 for ones with a smog pump. My manual is an original print from 1969, not repro.
     
  16. Dec 24, 2016
    1960willyscj5

    1960willyscj5 Well-Known Member

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    My idle got set by the amount of vibration the whole JEEP had at idle.
    I would increase the idle a bit, then a little more until the vibration went away, and the engine purred like a happy kitten.
     
  17. Dec 24, 2016
    eti engineer

    eti engineer Member

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    I can relate. I can crank mine way down and it will still run without missing a beat, but you can feel it every time a piston fires. It really feels smooth at 900 and at that rpm with the T-98A tranny, it is perfect for crawling. To each his own. Whatever works...


    One thing I did that took out a lot of vibration was replace the motor mounts. The old ones were rock-hard. I was amazed at how much vibration that took away. I would bet if I replaced the rear tranny mount it would decrease it even more.
     
  18. Dec 24, 2016
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    That would make me crazy.

    I'd have to wonder about the idle circuits in the carb.
     
  19. Dec 24, 2016
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    Me too but, ETI engineer has a 2 barrel Weber set up. I guess I'll have to get a tach now.
     
  20. Dec 24, 2016
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Right, I forgot that part. But then not really relevant to the OEM spec.
     
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