Oxford 330-1 Low on Power

  1. Daveylen93 New Member

    Messages:
    11
    Location:
    Ireland
    Hello have an Oxford 330-1 mig and it just doesn't seam like it has much welding power. I checked the voltage while welding in top setting 4-4 with a multimeter and it was reading 26-26.5 volts dc. Would this sound about right? It says on the plate on welder it should be capable of 30v on full power. Cant get into a true spray with 1mm wire and 86% argon co2 mix.
    Any help would be much appreciated.
     
  2. oilcooled :)

    oilcooled :) Pipe Welder, Mechanical engineer

    Messages:
    834
    Location:
    Ireland
    You prob want a 50 amp fuse on that welder and a decent cable running from the house to the shed 16mm2 supply cable, and if your out in the country the transformer on the electric pole might be under pressure I presume it’s single phase
     
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  3. Daveylen93 New Member

    Messages:
    11
    Location:
    Ireland
    Thanks for the reply. It's fed off a 32amp mcb and 10mm2 cable. Mcb never trips. Would voltage drop in the garage when welding make much of a difference to welder power output. I must check that 2moro see what voltage is entering the welder while I'm welding.
     
  4. eddie49 Member

    Has the machine always been like this, or is this apparent low power a new problem?
    Without load ( i.e. not welding ), what are the work return clamp-to-tip voltages as you step through the power ranges?
    Could be a bad connection in the high current path, or even an open-circuit diode in the rectifier.
    Can you try an alternate Eurotorch, and a different return lead?
     
  5. Daveylen93 New Member

    Messages:
    11
    Location:
    Ireland
    I havnt done any real heavy welding with it until lately so never really noticed. It's a 330 amp machine so should have more power anyway. I'll do some tests later that you said and see what I get ill post up. Cheers.
     
  6. Daveylen93 New Member

    Messages:
    11
    Location:
    Ireland
    Well did some welding there now and ran a few tests.
    With what you said to do I got 44volts on setting 4-4(max) and 40 volts on setting 4-3.

    While welding was 26.5 volts.

    I also had someone weld while I tested the voltage drop on the consumer board.

    Voltage was at 225volts ac and dropped to 208 volts while welding.

    Would this voltage drop on the supply make a big difference to welder output?

    Cheers
     
  7. Questions Member

    Messages:
    231
    Location:
    Dublin Ireland
    That difference in voltage will make a huge difference.
    When you say Consumer board, do you mean the one that
    supplies the electricity to your workshop.

    A friend had that exact welder, it did the same thing, other than
    putting a new gas regulator on it he then sold it to me, I never
    measured the voltage, but off hand 208 rings a bell, the regulator
    made a big difference to the weld though. I sold it on since I was never
    happy with it.
     
  8. Questions Member

    Messages:
    231
    Location:
    Dublin Ireland
    Before I sold mine, though I didn’t measure voltage, it had plenty of power,
    even with the bad regulator it had power, it was just not smooth.
    When the new regulator was fitted, it certainly sprayed, I note you say
    yours won’t.

    Diodes can cause poor power, there is 6 or maybe 8 used to carry the current
    While remaining reasonably cool and not as expensive as using only 2 larger
    ones, so I would check them, with power off, sometimes you can physically
    see the solid wires to the diodes are broke off, sometimes burning marks,
    other than that you need to test the diodes.

    Is your welder under warranty, was it welding better at any stage.
     
  9. Questions Member

    Messages:
    231
    Location:
    Dublin Ireland
    My one would trip a 32 amp breaker, it wouldn’t always trip it,
    I put in a bigger one, when I got fed up walking to the board to re set it.
     
  10. oilcooled :)

    oilcooled :) Pipe Welder, Mechanical engineer

    Messages:
    834
    Location:
    Ireland
    If u try it late at night when everyone in bed, see does it help, this time of year on a single phase supply the house draws a lot of current in the evenings between lights and heat and all that. If the house is sucking up the power don’t expect to be welding flatout on 300 plus amps, u can only draw what’s available. I was welding one night with a oil cooled welder welding away lovely on the vertical changed rod and welded away and it was a mess with slag ground out the mess and burned in another rod lovely. Someone boiled a kettle in the house that’s what drew the current and dropped my power.
     
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  11. eddie49 Member

    You are using 1mm wire .... when I enquired about the "Warrior" 250 Amp inverter MIG, the supplier told me that 1.0mm wire is good up to 250amps, any higher than that needs 1.2 wire. Can you try it with some 1.2mm ?

    That is a 17 volt drop, which is a 7.5 % decrease in AC mains voltage. As "Questions" has already asked, was this drop measured at the house? If so, what is the drop at the 32A socket in your garage during welding?

    This thread discusses a 12 volt AC mains drop when using an 8.5 KW shower, drawing 37 Amps - which is comparable to your welder ( 26 volts x 330 Amps = 8.6 KW ).
    https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=59761

    Is your house the last one at the end of the road? How thick are the meter tails - 16mm2 or 25mm2 ? How old is the wiring/consumer unit? How far is the garage from the house?

    You could get an idea of the state of the wiring by measuring the AC volts at the Consumer unit, at the breaker for the 10mm2 feed to the garage, then at the garage itself. Then switch on a heavy load in the garage - e.g. a 3KW fan heater - and repeat the measurements.

    Do you have access to a clamp-on meter? You could measure AC input current to the welder, and, if the meter is DC-capable, monitor DC current in the welder work return lead when welding at max.

    I have one of these, it measures DC Amps as well as AC, and has a "Hold" function so you can check the max current reading yourself after welding:

    https://www.ebay.co.uk/itm/YF-8030A...C-ELECTRICITY-TESTER-CAT-III-VGC/303376045569
     
    Last edited: Dec 6, 2019
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