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Grounding & hi frequency questions

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  • #16
    EMF is regulated and yes twisting, or tapeing cables will assist in controling the EMF. However it is hard for me to understand, theory, that will intensify the HF at the arc or that is will create a more stable arc, especially in an old transformer mach. As for grounding the Hf feedback put the rod in the ground, do not put it on your cold water pipe, you bleed current into the pipe and it will cause electrolysis and eat your pipe. If you have a pacemaker don't tig weld.

    Really there is extremely little amperage (next to zero) with HF alone, its just super high voltage.

    Are you a Tech Weld Bay?

    Comment


    • #17
      I am not sure what you are refering to, am a a tech yes, do I know everything no.

      Grounding electrical circuits, lke when you ground your washer, your welder or any electrical product will create electrolysis in copper pipe carrying water.

      Ground rods are simply the right way to ground a circuit, and if fact in most modern const, an earth ground is common.

      HF runs about 10,000 volts at almost no amps, it has a tendency to follow the path of least resistance in weld cable, runs more along the outside of the copper than the inside keeping resistance down and amps down.


      HF had a tendency to bleed into other circuit and causes frequency interference with radio signals, computors and cell phones., by grounding the circuit you substanilly reduce the amount of bleed and thus the affect of HF on surrounding electrical products.

      As for EMF and it's effect on the welding arc and the HF intensity I believe that tapeing or twisting the cables together will reduce the HF intensity and little if any affect on the arc. They actually use a switching EMF to move the arc back and forth in some weld applications.

      That said it is just my opinion based on what I beleive I know, if is is not right then correct that which I misunderstand, I will learn if not admit you are wrong and we can move on.

      Comment


      • #18
        Originally posted by weldbay View Post
        EMF is regulated and yes twisting, or tapeing cables will assist in controling the EMF. However it is hard for me to understand, theory, that will intensify the HF at the arc or that is will create a more stable arc, especially in an old transformer mach. As for grounding the Hf feedback put the rod in the ground, do not put it on your cold water pipe, you bleed current into the pipe and it will cause electrolysis and eat your pipe. If you have a pacemaker don't tig weld.

        I am willing to learn so please explain.
        Disclaimer: I am not a welding equipment design engineer and it would be nice if they would chime in and give us the official verdict but never the less I'll give you my view and you can consider it.

        There are no magic arc multipliers that create energy from nothing. What we are considering here is the intensity of arc at the end of an infinitely short set of cables versus the arc at the end of the real world cables. Anything that reduces losses in the system will "intensify" the arc closer to it's maximum. You could think of your cables as transmission lines as a long series of inductors and capacitors. The inductive reactance component shifts the phase relationship between the voltage and the current causing the current to lag the voltage(power factor). Close coupling the cables increases the capacitive reactance shifting the power factor back closer to the ideal of 1. As you are likely aware as your power factor deviates from 1 in either direction (that is: current leading or lagging voltage) the effective power in the system is reduced and this imbalance I believe would create instability in the arc. The correction as much as is possible in a real world system should deliver a more stable arc.
        As to whether or not the type of supply would make a difference(transformer or inverter) if we consider a nearly identical supplied wave I don't see why the supply should make a difference. If we were to use an inverter that could deliver customized waveforms well could be a whole new ball game but still doesn't negate the principal.
        With regard to grounding, I quite agree that a known ground is preferable to an unknown one. With the common use today of non-conductive plumbing these days it might not be advisable to use the plumbing on that count alone as you can not always be sure you are electrically connected where you expect to be.
        You might also want to consider connecting your "ground rod field" to your service ground for lightning protection. In my opinion an exterior to the building conductor is preferable. If you were to have a near lightning strike it could cause a substantial potential to arise on one of your ground systems but not simultaneously on the other. Significant current could then flow through your ground system in search of dissipation. This can result in dangerous voltages on anything that is grounded in your building until it finds the other ground and dissipates. It could damage equipment or you. Hope I'm not too far off the mark here and it makes some kind of sense.
        Meltedmetal

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        • #19
          Thank you for your response. In trying to understand, if I tape or twist my cables together closer to the source or nearer the lugs, would you not create a point where the HF might not bleed into the line at that point. If it did would it not decrease the intensity at the torch end. And I am not sure how decreaseing the EMF would assist an AC arc, and would have a neagative affect on a DC arc.

          If this is getting beyond the purpose of the Post then please contact me at admin@weldbay.com. I would really like to understand.

          Comment


          • #20
            Originally posted by weldbay View Post
            Thank you for your response. In trying to understand, if I tape or twist my cables together closer to the source or nearer the lugs, would you not create a point where the HF might not bleed into the line at that point. If it did would it not decrease the intensity at the torch end. And I am not sure how decreaseing the EMF would assist an AC arc, and would have a neagative affect on a DC arc.

            If this is getting beyond the purpose of the Post then please contact me at admin@weldbay.com. I would really like to understand.
            You the first person who questioned its validity, without trying it, as for DC tig, it doesn't really matter as the HF is only there until your arc is established, so 1/2 second maybe. Basically the taping is not needed on inverter machines as once the arc is established the hf turns off and the arc is maintained through the inverter.

            Only on transformer machines, its required to limit the amount of HF going everywhere searching for the torch. Taping the work and torch together focuses the hf with the final arc. It works suprisingly well. And stops the Radio from buzzing, garage doors going up and down, ect, ect....

            It's not nessesary to wrap your head around it. If you have a customer thats having troubles, quickily tell him what to do, and you won't have anymore phone calls from him. Simple as that,,, Again not getting into the very simple theory behind it.

            Comment


            • #21
              Lets agree that we both will cut down on RF interference. The fact is I have never seen anything in any manual that says it will in either case establish a better arc or create more HF intensity.

              If I have 25 feet of torch, 25 feet of ground, welding on an aluminum boat, ground at the stern weld at the bow And yor are saying twisting my cables together near the welder is going to solve the interference on the radio in
              the shop and give me a better arc and arc start.

              Please print this out, get it notorized and I will take it to Boeing, All American Marine, Nichols Boat, Todd shipyard and all the othermarine welders in my territory and on the web- promise.

              WeldCraft:
              9. How do I solve high-frequency-interference problems?
              Malfunctioning electrical equipment, such as computers, telephones and radios, is often a sign that you are experiencing high-frequency interference from your welding power source.
              To remedy such high-frequency interference, start by verifying that the power source is grounded according to the installation instructions provided in the operatorís manual. Keep your torch cables and work cables as short as possible, and place them close together. Physically separating your welding equipment from devices that may experience interference is also an option, but doing so can be time-consuming and space-prohibitive.

              Lincoln:
              High frequency signals have a tendency to radiate away from the welding area. These signals may cause interference with nearby radio and television reception or other electrical equipment. One method to minimize the radiation of high frequency signals is to ground the welding circuit. The welding machine instruction manual will have specific instructions on how to ground the welding circuit and components in the surrounding area to minimize the radiation effect

              Comment


              • #22
                Originally posted by weldbay View Post
                Lets agree that we both will cut down on RF interference. The fact is I have never seen anything in any manual that says it will in either case establish a better arc or create more HF intensity.

                If I have 25 feet of torch, 25 feet of ground, welding on an aluminum boat, ground at the stern weld at the bow And yor are saying twisting my cables together near the welder is going to solve the interference on the radio in
                the shop and give me a better arc and arc start.
                This is starting to get no where. Except that Weldbay is starting to look stupid arguing with cruizer at first postings.

                Weldbay, you can't give an example for cruizer to explain because it makes no sense. You can't expect a legitimate answer because if you are welding an aluminum boat and you connect the ground to one end and weld on the other and you are having problems, then you should understand that you need to move the connections closer together. And if you want to argue that, lets say the boat was in the middle of the ocean... or you are trying to weld a light bulb fixture to the tip of the tower on the empire state building, and your ground is in the basement.

                What happens when your equipment is portable? Are you supposed to stick a ground rod at every job?


                Stop trying to keep pushing your "book knowledge" and get out in the field like cruizer and do field tricks.

                What happens if your tire gets a hole in it and your stranded in the middle of the desert... You would wait for a tow truck as cruizer and I would stick a nail in the hole and get to the next station. You are both right, but when you are faced with a challenge you need to just get it done.

                Comment


                • #23
                  I sorry his profile says he is a welding tech, and your's is what a home shop welder.

                  Read this post you tell me:
                  T1 Transformer

                  You want to compare credentials, you want references to the projects I have consulted on or do you want to blow smoke.

                  I am contributing what I have expeirenced, first hand, if you can not stand another opinion then to bad don't get involved. Until then I will continue to agree where it makes sense and disagree where it does not.

                  This post ends here you guys can continue to believe whatever.

                  And you try to keep your ground close to the weld when you are making a deck seam weld on a 110 foot ferry.

                  Comment


                  • #24
                    And what about the T1 post, the guy had it to a Miller shop for repair, they told him is was a failed T1 transformer, and like I said, that would be a very rare occurance. might be alot of things. Have to remember that You nor I looked at the unit.

                    As for Boeing and such, I didn't start my life out as a Welder tech, I was doing Avionics/ Aircraft Maintenance Tech for 8 years, rebuilding anything from a small Cessna, Twin Otters to Hercs. Before that I was a Military Mechanic.

                    And YOU want to compare credentials. you won't even be close....

                    Comment


                    • #25
                      It is good to see youíve speculated all your moves in context to safety. Make it a point to work on your grounding. This is mainly because proper grounding eliminates most risks associated with high-frequency operations. Ground rods are cheap, but then they are not that reliable. The likelihood of most problems will be considerably reduced when you choose high-quality reliable equipment.

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