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  • High Frequency Interference

    Hi, I recently picked up a very lightly used, in perfect condition, Miller Syncrowave 180SD. I discovered a couple weeks ago while teaching my 17yr old nephew how to tig aluminum, the the high Frequency turns on ALL of the sprinkler valves on my property. My sprinkler timer is in the garage, semi near the welder, but separated by a 1200lb steel safe.

    I made sure to ground the work clamp to a clean spot on the table, close to the welding. Has anyone seen this? Is there any shielding that I can do? My sprinkler timer is wifi capable so I can control from my phone, so I can't put any major shielding, it would block signal.

    My electrical wiring is all correct, I am an electrician, 25yrs experience...

    Thanks
    2- Miller XMT 304, with 30A Spoolgun, 22A wire feeder and Suitcase 8RC wire feeder.
    Syncrowave 180SD with pulse controller.
    Miller MultiMatic 200.
    Miller Passport Plus.
    Miller MaxStar 150STL.
    Hypertherm Powermax 1000.
    Miller Spectrum 375.

  • #2
    There's a picture in the manual about how to ground everything to try to minimize interference, but the easy fix might be to turn off the sprinkler system (either power or water) when welding...

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    • #3
      Bushytails, turning the system off or unplugging it doesn't make a difference. It is actually inducing the voltage in the low voltage wiring to the valves.
      2- Miller XMT 304, with 30A Spoolgun, 22A wire feeder and Suitcase 8RC wire feeder.
      Syncrowave 180SD with pulse controller.
      Miller MultiMatic 200.
      Miller Passport Plus.
      Miller MaxStar 150STL.
      Hypertherm Powermax 1000.
      Miller Spectrum 375.

      Comment


      • #4
        Are you able to shield the signal wires to the valves, or is it all internal. Wifi runs off a 2.4GHz carrier frequency, where the HF should be about 1MHz, so I would think your WiFi receiver (transceiver?) isn't picking up the HF.

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        • #5
          A guess would be to try a different outlet...like the one in the neighbors garage

          Comment


          • #6


            I have little experience with solving HF interference problems with welders, but a significant amount in the world of electronics. Using those principles, I might try hooking the work lead directly to the part being welded rather than the table, but I really don't expect it to help. I would also try wrapping the torch and work leads around each other. Again, probably won't work, but worth a try.

            Originally posted by jjohn76 View Post
            Are you able to shield the signal wires to the valves, or is it all internal. Wifi runs off a 2.4GHz carrier frequency, where the HF should be about 1MHz, so I would think your WiFi receiver (transceiver?) isn't picking up the HF.

            jjohn, your statement sounds very logical, but unfortunately there are more things in play here. Not trying to be picky; you know I greatly appreciate your knowledge and experience. I have seen some truly strange happenings in the world of EMI related to computers and industrial systems over the years. Saw fixes people tried that worked and no one understood why, and fixes that were "absolutely guaranteed to work" that did nothing. Strange stuff. Yes, there is science in it, but there is a LOT of art.

            An "about 1 MHz" HF signal from a spark gap may interfere greatly with 2.4 GHz. wifi. By their very nature, spark gaps splatter RF energy across a wide spectrum of frequencies. And, since they were shooting for around 1 MHz, it might be around 1.2, and thus the very large second harmonic would be 2.4, right smack on the frequency of the wifi. Even if not on a harmonic, energy is still spread broadly and I would expect wifi interference to be more likely than not. Wifi that works around HF welding is a tribute to the wifi equipment designers' filtering ingenuity.

            Spark gaps are used in welders because other methods of producing HF are far more costly and bulky, and energy level is low enough that they usually don't bother the neighbors too much. Spark gap frequency generators were commonly used for Morse code transmitters back in the day, but were outlawed by the International Telecommunication Union in 1934, and specifically in the USA by the Communications Act of 1934. The reason was that they virtually all interfered with each other because of the energy "splattered everywhere" across the frequency band, so communication was becoming almost impossible as more and more people got into the game.

            Comment


            • #7
              Aero, makes sense. I am getting ready to mess around with a pilot arc HF and CNC plasma system. No WiFi, but have heard it's a pain to get rid of the interference. Hypertherm had a few good articles on how to chase down the interference, mostly making sure everything was tied directly to ground and all signal wires shielded with the shield connectedd to a chassis/ground. How are the water solenoid control wires routed?

              Comment


              • #8
                I would chase your ground and isolate the two and perhaps add another rod or field outside...........when I poured concrete here years ago I welded the rebar together in many places and brought up a #1 copper lead next to the shop..........I then ran a number #1 ground lead from there not to the panel but directly to the welder chassis.........No Hi-Freq problems here.

                Comment


                • #9
                  The solenoids on the valves are low impedance devices, and if you're inducing enough power to turn them on directly, something is wrong. You've tried unplugging all power sources (including any backup batteries larger than a coin cell) to the controller to confirm? What if you disconnect the wiring from the controller?

                  You could short the wires at the controller end, or turn the water off. Without knowing just how much power is ending up on those solenoids, turning the water off might hide that you're trying to melt them. You might want to measure the voltage on the wires running to the solenoids.

                  Some type of building ground issue is also a possibility, with the sprinkler wiring becoming a current-carrying conductor. Measuring just what's happening at the sprinkler wiring might identify this, if you measure both the lines to the sprinklers and the lines to ground.

                  Comment


                  • #10
                    Also, ensure that the sprinkler wire is not ran ran directly parallel to any mains wiring. (I'd edit the post to add this, but every time I edit anything the posts end up marked as spam...)

                    Comment


                    • #11
                      Could ferrite chokes on the sprinkler system wires fish out some of the offending HF?

                      There are formulas and calculators online to help determine where to place them on the wires to filter out various wavelengths...
                      Last edited by Helios; 09-21-2020, 03:25 AM.

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