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Grounding & hi frequency questions

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  • Grounding & hi frequency questions

    Is it a good idea to ground your welder to a grounding rod driven deep into the ground or connected to a copper water pipe. Also should ones steel welding table be grounded to the rod or water pipe. Then could your welding machine ground cable be connect to the same point on your table? Also I am woundering about transmission of high frequency through a building where there might be sensitive electronic equipment in use when one is TIG welding. What types of equipment might be effected and what could one do to minimize the effects or is there very little likelihood of a problem occuring. Thanks for your comments.

  • #2
    Try it first and see what happens before speculating about every possible outcome. The welder chassis is (or sposed to be) grounded thru the electric system.

    Comment


    • #3
      That said if you do not want your radio or tv to go crazy use a ground rod

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      • #4
        Problem is that when using a ground rod, and not knowing were the rebar is or the soil conditions, its kinda point less. Even tying into the copper pipe and not knowing if its tied into rebar is kinda pointless. Cause rebar goes everywhere that there is concrete.


        So either run an isolated ground from the machine back to the main breaker, Or tywrap your tig torch leads and work together for the first 2' after leaving the machine will minimize the intereferance.

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        • #5
          Ground rods are cheap, run the ground through the ext. wall and sink it outside the building. HF is a loose canon and always takes the path of least resistance. When you install a CNC Plasma cutting table, for example, I have sunk as many a 6 grounding rods to stop feed back.

          Comment


          • #6
            Cruizer, Please further explain your sentance below

            Originally posted by cruizer View Post
            Problem is that when using a ground rod, and not knowing were the rebar is or the soil conditions, its kinda point less. Even tying into the copper pipe and not knowing if its tied into rebar is kinda pointless. Cause rebar goes everywhere that there is concrete.


            So either run an isolated ground from the machine back to the main breaker, Or tywrap your tig torch leads and work together for the first 2' after leaving the machine will minimize the intereferance.
            "Or tywrap your tig torch leads and work together for the first 2' after leaving the machine will minimize the intereferance." What you suggested here was not quite clear to me. Please elaborate, Thanks

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            • #7
              HF tends to go everywhere as it searches for the tig torch. Tywraping the leads together, acts like a focused transmission tower, and minimizes any HF leakage.

              Very simple, and it works...

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              • #8
                What leads, the ground and the torch? Hf will bleed you are right but you need the HF in the Tung to initate the arc what you are suggesting would reduce the intensity and the amount of HF at the weld. I have seen Hf reduced just by leaving your 25 torch partially wound up on your cable holder and not stretched out as it should be.

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                • #9
                  Huh... it increases the intensity, and focuses the arc. WTF are you talking about?

                  It was only a suggestion, do it or don't

                  And yes the work and torch only for 2' after leaving the machine.

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                  • #10
                    I am not sure what WTF means but I will assume you respect this forums rules.

                    The first article is from Lincoln the second from
                    http://www.welding.com and this from me. You increas intensity by increasing the HF gap.

                    Now I do not claim to know everything so please explaine your theory. It seems to me that what you said "might" not make sense.

                    High Frequency Ground
                    Some welding machines utilize starting and stabilizing circuits that contain a high frequency voltage. This is common on Tungsten Inert Gas (TIG) welding machines. The high frequency voltage may have frequency components that extend into the megahertz region. In contrast, the welding voltage may be as low as 60 Hertz.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

                    What can be done about high frequency (HF) interference from my TIG welder?

                    A: Most HF problems can be solved with proper grounding. There are three items that are important to connect to a ground stake that you must install. They are the welding table, the base of the welding machine, and the electrical box on the wall that the machine is connected to. In most cases, this eliminates most of the problems.

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                    • #11
                      Hi frequency mitigation

                      Weldbay, Thanks for sharing those articales, they are right to the point. I would guess there suggestion that in addition to connecting the ground rod to the welding machine framework and the welding table, the disconnect and outlet where the welder is connected should also have their grounds connected directly to the grounding rod. Is that your understanding? Berol

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                      • #12
                        I am not sure what WTF means but I will assume you respect this forums rules.

                        Means What the fredrick,
                        anyhow, I've only been repairing welders and associated problems for 20 years. and have the respect from other techs, and run a warranty service center for all brands. I'm heavily factory trained don't have to explain any theory to you.

                        The best way to eliminate HF interference is the run a separate ground back to the main breaker.

                        Say if the ground is high in moisture, pounding a ground rod into it may agravate the situation.

                        But giver

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                        • #13
                          The way Cruizer says is well known....I have heard it said from other sources as well. I have never heard Cruizer steer anyone in the wrong direction.
                          From my own exp. I own a PORTABLE aluminum welding rig and I haven't had to drive a ground rod yet!
                          As for the tie wrapping the leads together.....that is what my dads pacemaker mfg's rep suggested to me. (actually I believe they suggested wrapping them for a good bit) Good enuff for me.
                          I prefer SBerry's ealier suggestion best tho. Simply run it and see what happens.
                          Older machines were way worse than newer inverter style Dynasty's etc.
                          The only thing I have on my shop machines is good wiring. No ground rods dedicated simply to any one machine. Everything works perfect for me.
                          I live in my shop and have tv's, computers etc, everywhere including IN the shop.
                          If your gap is set wide, I believe the problem worsens btw. I also realize some people DO suffer with problems so YMMV.
                          HTH, Garry

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                          • #14
                            Theory anyone?

                            Originally posted by weldbay View Post
                            What leads, the ground and the torch? Hf will bleed you are right but you need the HF in the Tung to initate the arc what you are suggesting would reduce the intensity and the amount of HF at the weld. I have seen Hf reduced just by leaving your 25 torch partially wound up on your cable holder and not stretched out as it should be.
                            You are talking about two very different animals here. When you wind your torch lead into a coil you have for all practical purposes created a choke coil(inductor) which will indeed impede the AC on the cable. As well it will shift the AC current out of phase with the AC voltage. I don't know the practical result of the latter but I'm thinking it is not particularly good.
                            When the leads are taped together the situation more closely represents a twisted pair which will help to equalize the inductance and capacitance along the length of the cable which should stabilize the AC portion of the arc. In addition if anyone ever bothered to read the EMF information in their manual they would discover that twisting or taping the leads together is one of the recommendations listed there.
                            Stay safe-Meltedmetal

                            Comment


                            • #15
                              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.

                              Comment

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