Lincoln Power Mig 140C Wiring

Discussion in 'Electrical Forum discussion & Blog' started by vstoyko, Jan 13, 2009.

  1. vstoyko

    vstoyko New Member

    Messages:
    6
    I just purchased a Lincoln Power Mig welder model 140C that Lincoln advertises as follows: “Wide 30-140 amp welding output range is the highest output in 120 volt input power welder class.â€

    In the operator's manual the requirement for the advertised maximum output states: "In order to utilize the maximum output capability of the machine, a branch circuit capable of 25 amps at 120 volts, 60 Hertz is required". The manual also states the recommended input fuse size is a 20 amp breaker and recommended input amps are 20.

    The design of the Power Mig 140C type 5-15P power cord input does not provide for 25 amps at 120 volts because no 25 amp receptacle exists where a type 5-15P power cord will plug into it. However it will plug into a 20 amp receptacle. It's not possible to obtain a 25 amp breaker or a 25 amp (or larger amperage) receptacle that matches the 5-15P power cord. Beyond 20 amps a 30 amp circuit is the next highest circuit according to industry practice.

    I certainly would appreciate any suggestions or insight in how to safely and legally obtain the advertised maximum output of my new welder without modifying the welder's NEMA Type 5-15P power cord.
  2. jwelectric

    jwelectric Electrical Contractor/Instructor

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    2,534
    Location:
    North Carolina
    Install a 20 amp circuit with a 20 amp receptacle and plug in the welder and burn up some metal
  3. vstoyko

    vstoyko New Member

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    6
    Thanks jwelectric, I wish it were that easy. By going the 20 amp circuit route the 140C welder will max out at delivering 120 amps DC instead of the advertised 140 . I suppose if there's no other alternative I'll have to go with the 20 amp circuit. It really bothers me that Lincoln advertises a 140 amp output when (as far as far as I can see) there is no legal way of achieving it.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    It's possible that that is a peak rather than continuous rating, and that it will produce that, for a moment. CB take awhile (usually) before they trip when the current is exceeded - could be a very short time or seconds, or maybe even longer.
  5. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

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    996
    Location:
    NY State, USA
    Here is my reply from another forum you posted this to:

    You would definitely need a 30A/120v circuit for this. Even that is technically non-complaint since it would violate the individual load rating of 80%.

    Do they give an advice on how to obtain this 25A/120v input? Such as changing the cord set?

    There is NO WAY you will be able to safely and legally obtain a 25A input with typical 15 or 20A receptacles and circuits.

    I gotta ask, why didn't you just get a 240v welder???
  6. helix3

    helix3 Sr. Systems Engineer, Biotech

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    Location:
    Northeast
    I replaced the ridiculously short 6' and power cord on my Lincoln 175 with 25' length of 8/3 SOOW. I also ran a dedicated 40A line to the garage using 8/2. I've been happily melting metal for 5 years with it. The duty cycle of the welder says a lot for what it actually draws from the wall.
  7. vstoyko

    vstoyko New Member

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    6
    Speedy Petey, I bought the 120 volt welder for portability and the availability of 120 volt outlets (away from my garage) as well as the relatively light material I weld. My fault for not going beyond the advertising and investigating the real world capabilities of the welder. Output at 15 amps will be be approximately 90 amps DC. I would prefer to have the full 140 amp capacity in my garage so I've been thinking of a 30 amp 120 volt circuit with 30 amp receptacle and using an RV converter to plug the NEMA type 5-15P into.
  8. jar546

    jar546 In the Trades

    Messages:
    432
    Location:
    USA
    I went to the Lincoln website and looked at the owners manual for your welder.

    All you need is a 20A circuit and you are perfectly legal and will achieve the full output range on your welder.

    You can run a 20A circuit with 12awg wire and even use a 15A receptacle and you will be fine and code compliant.

    Plug it into any 20A circuit that is not running anything else and it will work to its full capacity.

    120 V 60 Hz 20 Amp 20 15 Amp, 125 V, 3 Conductor # 12 AWG
    Three Prong Plug (4mm2) or Larger
    (NEMA Type 5-15P)
  9. jar546

    jar546 In the Trades

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    432
    Location:
    USA
    You have a 120v model, don't try to use 30A as it will not help you the way the unit is set up. Call Lincoln and aske them.

    If you planned on needed at least 140A for mig then you should have upsized.

    This is a handy unit and I used it in the past with argon.
  10. vstoyko

    vstoyko New Member

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    6
    jar546, excerpts from the 140C manual:

    Standard Voltage/Frequency Input Current
    120 V / 60 Hz 20 Amps @ rated output

    Rated Output
    Duty Cycle Current Voltage at Rated Amperes
    20% Duty Cycle 90 Amps 19.5 volts

    Welding Current Range Open Circuit Voltage
    30-140 Amps 33 V

    Fuse or Breaker Size 1,2
    20 Amp

    1. If connected to a circuit protected by fuses use Time Delay Fuse marked “Dâ€.
    2. Requirements For Maximum Output
    In order to utilize the maximum output capability of the machine, a branch circuit capable of 25 amps at 120 volts, 60 Hertz is required.

    As you can see the input current is 20 amps @ the rated output which is 20% duty cycle, 90 amps and 19.5 volts.

    It's not that I have an immediate need for the advertised 140 amps....It's the manufacturer's questionable advertising that causes the problem. Should I need the full capacity (140 amps) in the future it's not available. Not exactly goods received as advertised and definitely a bit of deception.

    I emailed Lincoln support 3 days ago and the automated response I received stated that they try to respond in 2 business days but I'm not holding my breath on receiving any type of support.
  11. jar546

    jar546 In the Trades

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    432
    Location:
    USA
    Yeah I see the problem. The plug that comes with it and the rating say one thing. In order to get maximum amps you need another. Problem is that they say you need it but don't have it set up to accept that. You would have to make an illegal install in order to gain maximum amps unless they can provide you with better manufacturer installation specifications.
  12. jimbo

    jimbo Plumber

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    8,997
    Location:
    San Diego
    Kind of like the Horsepower number you see on vacuum cleaners, shop vacs, etc. They show a large HP number in BIG print, and fine print will say that is "peak" or something like that. It is NOT a 4 HP motor!

    Sometimes, like in pool pump motors, they use an HP rating + service factor multiplier. You have to read all the fine print.

    Or, like PT Barnum said, there is a sucker born every minute!
  13. helix3

    helix3 Sr. Systems Engineer, Biotech

    Messages:
    28
    Location:
    Northeast
    Being in the fitness industry for 5 years, there was always a competetor that would try to throw something out there. Our 120V treadmills were rated 19A, 3HP continuous duty. Competetors had 120V treadmills with 6HP - treadmill-duty motors. I'd always get the question at tradeshows. No problem, I'd show them a 1200V SCR spike, then claim ours to be 30HP treadmill-duty. Then I'd show them how it all gets calculated. It usually cleared things up well.

    My mother-in-law wants to buy one of the Black and Decker cordless mowers. They have two out there to look at. The spec on one only states '12 Amp'. The spec on the other only states '24 Volt'. How about they give me both numbers for both mowers?
  14. Thatguy

    Thatguy Homeowner

    Messages:
    1,459
    Location:
    MD
    33Vx140A=4620W=39A@120V.

    A Q0 20A breaker can deliver 40A for 8 to 28 seconds before tripping.

    Advertising fraud?
    Dunno'.

    I don't weld, but I think they're depending on average current draw being within a 20A breaker's capacity most of the time. If you have some weld that takes 140A for more than 8 seconds you might be inconvenienced.

    Can you post a schematic/parts list? I'm thinking the 20% duty cycle depends on the internal transformer's I-squared-T rating. The whole setup might depend on assumed I-squared-T ratings of wires, sockets, breakers, everything.

    If anyone has a link to welding current vs. time I'd sure like to see it.
    Last edited: Jan 14, 2009
  15. codeone

    codeone Code Enforcement

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    160
    Location:
    North Carolina
    My dad was a welder for a living. He used to tell me that the 20% duty cycle meant that the welder was good for only 20 min out of an hour. If you used it longer the unit would burn up because the temp ratings on the windings couldnt handle the heat.

    Dont know myself. However if you need more youll have to get a higher duty rating.
  16. jar546

    jar546 In the Trades

    Messages:
    432
    Location:
    USA
    I will need an explanation to see how you are using the power factor for the secondary side of a transformer to calculate amperage on the primary AC side.

    I am lost.
  17. vstoyko

    vstoyko New Member

    Messages:
    6
  18. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,019
    Location:
    New England
    20% would be 12 minutes in an hour. Most jobs have a fair amount of setup and cleanup in between when actually welding, so that may not be a major deal. An industrial unit that can run 100% of the time would likely be much more expensive.
  19. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,534
    Location:
    North Carolina
    Hey dude I think you might be on to something right here. Why else would the people that built that damn machine put a 15 amp rated plug on unless that is all it needs?
  20. vstoyko

    vstoyko New Member

    Messages:
    6
    Gentlemen, thank you all very much for your assistance and insight. It was all very good information. I found the answer to requiring a 20 amp circuit breaker while also requiring 25 amps available to that circuit in order to obtain the full output of the welder. As others have suggested, it's in the circuit breaker design and test criteria. The following is an excerpt from a circuit breaker manufacturer that explains the current carrying capabilities of most circuit breaker:

    The CSA test program as well as our inhouse test program confirms compliance with the regulatory requirements by conducting the following tests:

    Initial Trip time confirmation

    * The breaker is "over loaded" to a value of 135% of the current rating and the breaker must trip within one hour.
    * The breaker is then "overloaded to a value of 200% of the current rating and the breaker must trip in typically in less than two minuets.


    Temperature test

    * The circuit breaker is overloaded to a current value of 6 times the rating ( but not less than 150 amp.) and switched 50 times.
    * The circuit breaker is then placed in a 40 deg. C. ambient temperature and forced to carry 100% of the current rating until the circuit breaker reaches thermal equilibrium. Temperatures are recorded and must be below the maximum temp. limits of the requirements.

    Considering the welder's duty cycle it will operate at the 140 amps advertised by Lincoln so my previous assumptions were wrong.
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