Power Arc 4000
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Thread: Power Arc 4000

  1. #1

    Question Power Arc 4000

    Just traded for a Power Arc 4000, and it is not generating power at the outlets or weld leads.

    I checked the brushes and cleaned the contact areas on the rotor with emory cloth, and replaced the two bridge rectifiers (D1 and D2). I took the capacitor out and had it checked, shows to be good.

    Can anyone familiar with this unit tell me what I might look for next?

    Thanks

    Tony Roper
    Abilene, TX

  2. #2
    Join Date
    Mar 2010
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    Ceres, California
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    Re: Power Arc 4000

    Please post the code number, so i can look at the right diagram.
    Make sure D1 &2 are installed right. D2 might only have 2 wire going to it.
    Check D1 AC terminals and see if there is any voltage there.
    Then we can dig deeper

  3. #3

    Re: Power Arc 4000

    The code number is 10202, some photos of the setup follow.

    I had read other posts on this board and decided to try applying flashing current to see if the welder would perk up. At operating speed, applying 12V to the rotor ( + to the positive lead of the capacitor and - to the chassis ground nut) seemed to change the RPM slightly but there was no power generated. Using a VOM at the brushes, I get no more than half a volt AC. I think this should be the same as the D1 AC terminals?

    I believe the oil switch is faulty. I found it to be disconnected. While the engine has plenty of oil in the crankcase, hooking up the low oil switch causes the engine to die.





  4. #4
    Join Date
    Mar 2010
    Location
    Ceres, California
    Posts
    2,438

    Re: Power Arc 4000

    Got it back wards. The brushes are DC. The black and red wires
    The blue wires should have a 7 and a 9 on them. They are AC voltage from a exciter winding in the stator. The red wire on both diodes should go to the positive DC terminal. Marked with a flat on the corner. Black is the negative on the opposite corner.
    The AC terminals are some times marked with the ~ symbol.
    If there isn't any AC voltage on wire 7 & 9.(engine running).
    Disconnect wires 200 and 201 (red and black wires) from D1.
    200 is pos. and 201 is neg. and connected to battery ground.
    Apply 12 DC to these wires and turn output control all the way up.
    See if the welder comes to life. All output voltages are AC. Weld and aux power.
    Check all the plugs and the weld terminals.
    Resistance from slip ring to slip ring is 8 to 9 ohms and with brushes unplugged.
    Should be more than 500,000 ohms slip ring to machine ground.
    When working right. The brushes should have 45 to 48VDC on them.
    Wires 7&9 should have around 33 AC volts.
    You should have a diagram on the inside of the cover.
    Make some tests and report back to us. Carefully log your test set up and results. so I can follow it.
    You may be right about the oil pressure switch. It is normally closed and only opens when there is oil pressure. Check it with an ohm meter.
    This is a second problem and will not keep the welder from working.. see if you can find a pressure gauge and make sure you really have oil pressure.
    Last edited by ccawgc; 03-24-2011 at 02:37 AM.

  5. #5

    Re: Power Arc 4000

    Thanks for the insight. I went and tested things just now, using a little 12V car booster for a 12V source and an old Fluke 77 for everything else.

    With engine running, there is 0.87 VAC across wires 7A and 9A. I disconnected wires 200 and 201 from the rectifier and applied +12V to wire 200 and -12V to the ground stud. This produced a noticeable change in engine pitch. Measurements at the weld leads were 0.9 VAC, 0.3 VAC at the 110V outlet, and 1.0 VAC at wired 7A and 9A. I attached a small load (100 watt light bulb) to the 110V outlet and observed no change in engine pitch nor voltage at the 110V outlet.

    I checked both circuit breakers for continuity, they show to be OK.

    I think the oil switch on this unit is to detect the presence of oil rather than any pressure - don't think this one is a pressurized setup. I'll see if the local lawn mower shop has a replacement since I don't like disabled safeties, ever.

    Measuring at the slip rings (engine off now!) I get 7.2 ohms between rings, 1.4 M ohms between the positive ring and ground stud, and an infinity reading between the negative ring and ground stud.

  6. #6
    Join Date
    Mar 2010
    Location
    Ceres, California
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    Re: Power Arc 4000

    If you have 7.2 ohms at 200 and 201. The engine slows down when 12VDC is applied to 200 and 201. Nothing is connected to any output terminal.
    This makes me lean towards a shorted stator. At this point if it was in my shop I would try to apply full rotor voltage, monitoring the rotor current and watching for smoke coming from the stator. You can get a flash light or inspection camera and look at the end of the stator coils. Look for burnt lacing and discolored wires. Also check the wiring between the weld terminals and the stator. Make sure nothing is shorted. This is a simple machine and ther is not a lot to it. when compared to other welders.

  7. #7

    Re: Power Arc 4000

    Will take a look at it this evening and see if I can detect any obvious problems with the stator.

    I have a moderately equipped garage at home but have never tackled a welder or generator. What, if any, specialized tools are needed to remove and reinstall the stator?

    Thanks

    Tony

  8. #8
    Join Date
    Mar 2010
    Location
    Ceres, California
    Posts
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    Re: Power Arc 4000

    You don't want to pull it apart. look in the vents, maybe just remove the rear plate.
    If you were to disassemble it completely. Leave the rotor attached to the engine.
    You remove the engine and rotor as a unit and leave the stator wired in.
    If there are not to many wires you might be able to mark the wires and disconnect it and slip it off the rotor. Should be 4 long bolts that hold the stator assembly together.
    Looking at the parts manual it appears there is a front and back shell, stator is inside.
    The rotor is held on with a long bolt up the inside an a tapered shaft at the engine.
    The idea here is to get the best look inside with out taking it apart. Looking for anything that is different, discolored and melted.
    I have not taken one of these apart. So I can only speak in general about it.

  9. #9

    Re: Power Arc 4000

    Update: took it to the local shop that is a Lincoln service center for diagnosis. The guy at the counter was full of dire warnings about the stator, saying if it is out it would probably be close to $1000 for the repair. Hopefully he's incorrect about the price, my total budget ceiling for this welder is about half that figure. Will update when I get an actual diagnosis.

  10. #10

    Re: Power Arc 4000

    Update: Repair shop found a little copper tab on the 110V outlet that should have been broken off during installation. Also found was a 1" crack in the fuel tank that only leaked while the engine was running. Welder tested good under load but engine seems a little weak. Bill was a little steep but the missed diagnosis was worth a lot.

  11. #11
    Join Date
    Mar 2010
    Location
    Ceres, California
    Posts
    2,438

    Re: Power Arc 4000

    The last owner changed the receptacle then didn't known what he did and the welder wouldn't work for him. Is my guess.

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