No announcement yet.

High OCV

  • Filter
  • Time
  • Show
Clear All
new posts

  • High OCV

    Hawk, we were discussing DialArc 250's recently. I checked the ocv on mine this morning, it is about 125 volts. The plate says 75 max, so I would conclude that maybe it has issues. It was set for 230 volts and I was running it on 208V. That way the ocv was 110V. So I changed it over and checked it again. Not a big deal, I enjoy using my xmt304 immensely. I don't feel like spending any money on it anyway. What do you guys think about the apparent high ocv?

  • #2
    If I were you... one of the things that I would do is a differential voltage measurement... that is


    Hot Lead and Work lead
    Hot Lead and a true earth ground
    Work Lead and a true earth ground
    Machine case and a true earth ground

    also what settings are on the machine? and are you measuring VDC or VAC

    these measurements will help to determine if there is real leakage or not..
    this is a start.. then depending on what you get we can go from there..
    hope this helps

    The more you know, The better you know, How little you know

    “The bitterness of poor quality remains long after the sweetness of low price is forgotten”

    Buy the best tools you can afford.. Learn to use them to the best of your ability.. and take care of them...

    My Blue Stuff:
    Dynasty 350DX Tigrunner
    Dynasty 200DX
    Millermatic 350P w/25ft Alumapro & 30A
    Millermatic 200

    TONS of Non-Blue Equip, plus CNC Mill, Lathes & a Plasmacam w/ PowerMax-1000


    • #3

      I don't know if that's a real issue or not. Someone at Miller needs to tell us how they arrive at OCV. Is it DC OCV between the work lead and the electrode at the machine or is AC RMS or what. I honestly am not sure how it is measured. Maybe Kevin at Miller will chime in?


      • #4

        I have had several people tell me what great machine the Dial Arc is. I have welded with 3 different machines and have not liked any of them. I guess that's just me?


        • #5
          Sorry, I should have said that it was DC, with a digital meter, right at the machine output. I checked the AC also, but don't recall what it was. Probably be there tomorrow morning and will check out the Ac as well as what Heiti was mentioning.

          All I know is that the DRO on my 304 is within 0.1 volts of what my digital multi meter says, so I can't argue with that. It usually runs at about 84.8 to 85 ocv.


          • #6

            I emailed Kevin @ Miller and asked him to help us out. Maybe we'll here from him tomorrow. Have a good Sunday afternoon.


            • #7
              I checked it again. The DC shows 125.4 ocv. The AC shows 79.4 ocv. The range selector and the current control do not affect the readings at all. I would be inclined to think that the Ac is ok as the sticker says max 75, and 79.4 is close enough.
              The readings between the dc + and - to the actual ground screw at the line in start at about 2 volts and with in 30 seconds gradually drop down to 0.1 volts. Same on - as +. On the ac output one shows 0.8 vlts to ground and the other shows 0.2 volts to ground. So maybe Kevin has some insight.
              Does anyone out there have a Dial arc 250 and that could just check ocv across dc output? Just curious to see what is "normal".



              • #8
                The AC OCV reading you are getting is right about where it should be but the DC reading is over the norm (about 70 VDC). A standard DVM should give you the correct readings. I would suggest trying another meter to be sure its not just a meter problem. If it tests high on a second meter you should discontinue using it and get it checked out at a repair center as there could be a serious problem.


                [email protected]
                Kevin Schuh
                Service Technician
                Miller Electric Mfg. Co.