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  • Grumpy
    replied
    Thanks everyone. I learned quite a bit from this thread. Interesting reading. I agree that if the ground and stinger lead were together then they would cancel each other. I'm not sure if I run the blame thing long enough for the leads to heat up. Based upon other threads I feel it's safe to leave them coiled provided I have no more that 50 feet or so with about 20 feet uncoiled. Thanks again guys.

    Grumpy

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  • INTP
    replied
    Originally posted by rick-l
    On the input side the wires are usually tightly coupled (physically close) to its return so the magnetic field created by the curent flowing into the device is cancelled by the equal and opposite current flowing out.
    This is a possibly important distinction. When the hot and return side of a circuit are run in close proximity, they cancel each other's magnetic field, which also offsets the inductance. This is a key restriction of NEC in that the neutral and the hot wireds must be run in the same cable or conduit. With the wires run separately, the inductive effect would heat the wires and lead to increased risk of fire.

    I suspect that if the welding leads were coiled together then the effect of coiling them would be much less.

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  • rick-l
    replied
    A choke and a reactor are just another name for inductors. Inductors store energy in the form of a magnetic field. An inductor's ability to store energy for a given amount of current flow is called inductance. It is also a measure of the intensity of opposition to changes in current.

    A straight piece of wire has an inductance (relatively small), a coil of wire has a bigger inductance (the magnetic fields add) and a coil on a steel wheel hub can store even more magnetic energy.

    When you try to increase current in an inductor, it acts as a load dropping voltage as it absorbs energy [v = L di / dt]. The current through an inductor cannot change instantaneously.

    I’m not sure how this affects welding. When you strike an arc with DC the current would ramp up slower with an inductance in series (coiled wire) but I don’t know enough about the size of the resistance ( R ) and inductance ( L ) of the circuit to guess at how much. If the process used High Frequency AC to aid starting the arc the inductance might reduce (choke) the AC component.

    On the input side the wires are usually tightly coupled (physically close) to its return so the magnetic field created by the curent flowing into the device is cancelled by the equal and opposite current flowing out.

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  • ASKANDY
    replied
    In an AC circuit, the coil is called a reactor and also is a way to vary current but in a DC circuit it is a choke or inductor. The term choke refers to what it does to current rushing through it...it chokes it off.

    A-

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  • kdahm
    replied
    Inductance is both DC and AC

    It is just a lot more noticable in DC.

    When you coil the wire, the current creates a magnetic field. (simplistic explanation). If a magnet or a soft iron core is placed in the center of the coil, the magentic field is enhanced, by lining up the crystals in the iron. On a DC circuit, the magnetic field is at a constant strength because the current and voltage are constant. In an AC circuit, the magnetic field is constantly varying because the current and voltage vary.

    Transformers and electromagnets work on this principle. The major difference is that the wire is led through a single loop, rather than a coiled double wire. With welding wire, the stinger wire creates one magnetic field and the ground wire creates another. Since the current in the paired wires is running in opposite directions, the combined magnetic field is much weaker and has a lot of eddies and distortions. More heat is also produced, because the magnetic fields are each trying to induce a current in the opposite wire.

    It's been a few years, but if anyone wants a more detailed explanation, complete with calculus....

    Watch out for your credit cards or floppy discs when walking near long coiled welding lines.

    Karl

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  • glockdoc
    replied
    Thought the inductance thing was an AC circuit trick along with transformers and induction motors. Guess an inductance can be created in a DC cricuit if the current is varied such as manipulating an arc or striking an arc. I'm still trying to figure this stuff out.

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  • Sberry
    replied
    That 0 wire is plenty good for input.

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  • ASKANDY
    replied
    dyn,

    That's plenty!

    Have at it.

    Andy

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  • dyn88
    replied
    point taken. When I cunsulted the electrical house, they assured me that 0/3 so would be plenty large for the 110 amps my machine would pull at full load of 208 volts. is this untrue and what size cable should i be runing.(the 3/0 is three cunducters at 0 guage each)

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  • ASKANDY
    replied
    No... The AC side of the power cord does not cause an inductance. An inductor or choke os only in a DC circuit. You will have a voltage loss if the cable is not sized right but that is all.

    Good question!

    A-

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  • dyn88
    replied
    I have a 150' 0/3 so cord on my lincoln 300/300 a/c d/c and I used to keep it coiled around a car rim on the wall. When Id weld thick aluminum My shop helper said that he could actually hear the rim hum and when he touched the cord he claimed it vibrated and got warm. Since then I use a 3 pin hub and keep 100 feet in reserve, I have noticed a diference in the a/c arc.

    Also the magnetic field can occur even on a straight cord. When we carbon arc gouge with 3/4 and up carbons at 1200 and up amps you can see all the grinding dust form little lines on the ground under and on the power and ground cords(they are copper too).

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  • cope
    replied
    Originally posted by ASKANDY
    Actually, leaving your cables coiled up will cause a magnetic field that hampers amperage to the arc especially at start up. The answer is to put quick disconnects every 25 ft so you can hook up smaller portions of weld cable when needed. The higher the amps you are welding at the worse the starts will be. You are creating, in electrical terms, a choke or inductor. An inductors purpose is to oppose and changes in current and that is why when you are asking for a large inrush of current to start the arc, the coiled up weld wire and electrode wire will slow down the available current. With only 50ft coiled, it may not be that bad but I've been to job sites where 100 -150 ft were coiled up and while welding, I could stick my leatherman to the side of the machine frame and it would magnetically stick until he stopped welding!

    Hope this helps.
    A-
    Andy,

    Is the same true with the input power cord/ewxtension cord?

    I have 60' of #2 on my Miller stick and its too much trouble to uncoil it every time I weld. Whenever I have to use an extension cord I have made sure it wasn't coiled up.

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  • INTP
    replied
    I believe you should feel the heat from the induction in the wire if you use it long enough with enough power. If your leads get hot, then uncoil them.

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  • ASKANDY
    replied
    Actually, leaving your cables coiled up will cause a magnetic field that hampers amperage to the arc especially at start up. The answer is to put quick disconnects every 25 ft so you can hook up smaller portions of weld cable when needed. The higher the amps you are welding at the worse the starts will be. You are creating, in electrical terms, a choke or inductor. An inductors purpose is to oppose and changes in current and that is why when you are asking for a large inrush of current to start the arc, the coiled up weld wire and electrode wire will slow down the available current. With only 50ft coiled, it may not be that bad but I've been to job sites where 100 -150 ft were coiled up and while welding, I could stick my leatherman to the side of the machine frame and it would magnetically stick until he stopped welding!

    Hope this helps.
    A-

    Leave a comment:


  • Sberry
    replied
    I leave mine wound up and use just what I need, I doubt it makes any real difference especially at low amperages with relatively short leads.

    Leave a comment:

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