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Electrical connection requirements

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  • Broccoli1
    replied
    Originally posted by unionsparky View Post
    Yeah, working now. They're closed, unless someone has a special number. To be more specific, their service is running ' hot ' at 125V/248V, and 211V high leg. I'm hoping the controls, if derived from 120V are being pulled from A phase. If they are 230V, I hope the welder handles the higher voltage ok.
    120v Control voltages are supplied from inside the machine via a transformer since there is NO NEUTRAL in the supply circuit.

    Leave a comment:


  • unionsparky
    replied
    Originally posted by Bodybagger View Post
    You might want to give Miller a call and ask them about powering this with unbalanced three phase and see what their engineers say.
    Yeah, working now. They're closed, unless someone has a special number. To be more specific, their service is running ' hot ' at 125V/248V, and 211V high leg. I'm hoping the controls, if derived from 120V are being pulled from A phase. If they are 230V, I hope the welder handles the higher voltage ok.

    Leave a comment:


  • Bodybagger
    replied
    I had a similar experience with a Lincoln Power Wave 455... previous owner had it connected to a 120/240 three phase with a high leg. The machine would randomly shut down and the owner just thought it was unreliable. I ran it on a 208 three phase and never had any issue. I think in the previous owner's situation, the wild leg would get outside of the voltage tolerance when other loads in the shop changed, and that's what I figured was going on when I picked up this pulse-spraying beast for a song.

    In this case, I spoke with engineers at Lincoln and they confirmed that the supply voltage was sensed from the L1 and L3 input terminals.

    You might want to give Miller a call and ask them about powering this with unbalanced three phase and see what their engineers say.

    Leave a comment:


  • unionsparky
    replied
    As long as I have the control board set for 230V, will welder care which leg is high leg?

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  • WillieB
    replied
    I believe you can use a overcurrent device up to 200% of the nameplate I1eff, or 200% of nameplate current x multiplier from 630.11(A) What is the duty cycle of the welder?

    It is my opinion that a disconnect switches load only in extreme emergency. Its requirements are the same as the conductors supplying.

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  • Broccoli1
    replied
    Originally posted by unionsparky View Post
    Sorry. Disregard. I am not as familiar with Art. 630 than I should be. So I guess the actual question I have is will this welder operate properly connected via 30A non-fuse disconnect, #10 wire
    Are you talking about a normal Circuit Breaker?



    3-phase 240v 30amp CB and 10g wire

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  • unionsparky
    replied
    Sorry. Disregard. I am not as familiar with Art. 630 than I should be. So I guess the actual question I have is will this welder operate properly connected via 30A non-fuse disconnect, #10 wire
    Last edited by unionsparky; 10-17-2014, 01:30 PM.

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  • Broccoli1
    replied
    It is allowable due to the machine' duty cycle.

    Normal operating FUSE you would use a 50amp fuse and 10g wire IS MINIMUM
    Wiring following NEC art 630 wiring and that is what they use for the manual.



    Time delay fuse = 30amp rated and 10g wire.

    http://www.millerwelds.com/om/o1327ah_mil.pdf

    Leave a comment:


  • unionsparky
    started a topic Electrical connection requirements

    Electrical connection requirements

    Hello all! I'm not a welder, but an electrician. I have a customer with a MillerMatic 350. We are to connect it to 3 phase 240V. The specs clearly state 30A draw and minimum conductor is #10. The personal at technical support just told me that I should install a 50A breaker and that a 30A safety switch would not be adequate. Am I crazy or does it just seem like he is not understanding or doesn't know. At minimum wire size of #10, a 50A breaker is illegal.
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