HF problems? Machine or shop wiring?

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I'm only recently getting some quality time with my new to me Syncro 351.  I fooled with TIG many years ago doing automotive work.  But I was never trained, and while I got by, I really never knew what I was doing.So now I've got this new machine and welding some scrap pieces, and a few non-critical (non-visible) projects.  Mostly 1/16 to 3/32 steel using DCEN, 3/32 thoriated, sharp point, 1/16 copper plated steel filler wire (Hobart brand I think?), ~110 Amps max, HF start, and the foot pedal.So, very first test welds a few weeks back.  I had a Luxor magnification lamp on the back side of the weld table for years, never a problem.  But current went through the cord burning it up, luckily the cord is all so I repaired and relocated off the welding table.  This weekend using it again.  I usually use a 500W halogen lamp to light the work, helps me see.  I barely got started, blew a bulb.  Noticed the extension cord for the light had gotten crossed up with the torch leads, figured that got it.  Ran cord to opposite side of shop well away from torch leads.  Building a light duty stand from 1/16 wall 1" square (and such), and in maneuvering around I got the ground on opposite side from the arc.  Brushed arm against stand frame and got "tickled" pretty good.  Hmm, that wasn't fun.  Surprised it liked me better (wearing good insulated sole boots on a rubber mat) than the ground clamp only a few inches past me, but "don't do that again".Not long later I noticed I was having a slightly harder time seeing with the arc off (Speedglass hood).  Blasted second work light blown.  Those lights have been in frequent use for 6 months without a single burn out, so not a coincidence I'm sure.So, is this likely a problem, and if so, what?  The shop wiring seems to be well above code in every way (PO of my property used it as a CNC machine shop).  But other than my complete lack of skill (improving, slowly as you might expect), this seems to be the only problem so far.  Once I sort this, if I can just learn to keep the filler out of the tungsten I think I might just like this rig.  But I'm a long way from trying aluminum (which I never could weld).
Reply:What do you have the hf set at. Turn it to 10-15 percent.
Reply:Take a look at the Miller manual for the machine. It suggests grounding the machine, parts of the electrical system  and metal structures to avoid HF interference problems. That may or may not help with your issues..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Is the table grounded? Not just with the "work" clamp but actually grounded?Idealarc 250AC 225SVictor OA-older made in USA stuff.And a crap ton of other stuff.
Reply:The sync 351 has no HF control (that I am aware of, at least not on the panel) other that start/off/on.  Isn't that an inverter only feature?The machine casing is grounded through the 220V power cord.  The machine is mobile and needs to remain so since I have 2 outdoor "bays" (sort of) where it will also be used, well beyond the 25' torch leads.  So if it needs additional separate ground I'm not sure what it would be, other than maybe a 110V plug (minus power/neutral connection) utilizing that ground?  I suppose it could be a separate ground clamp, but the outdoor bays don't have a good ground handy other than outdoor outlets.  Not sure what I should do on this.  Any other suggestions?  In any case, I thought that meant more for "noise" in fluorescent tubes/ballasts, radios, and other RF sensitive devices.  And no, the table is not directly grounded.  It sits in the open near the middle of the main shop slab.  The only way to get an independent ground would be to drill through the slab and sink an extra rod.  Is that what you are suggesting?Also, by the seemingly tentative answers, I would guess that my apparent problem is not common?
Reply:Regarding grounding the machine chassis independently, I was just thinking I could replace the long 3 conductor power cord with a 4 conductor as used on 3 phase machines.  That would give me an extra dedicated ground for the chassis.  I could then run and independent ground rod at that outlet location.  But I've always considered multiple ground rods a bad thing in general.  Not sure on this point.  Any and all suggestions welcome, thank you.
Reply:It occurred to me that when I was inspecting the machine and checked the points, there was a dial down there.  Haven't thought about it since.  Went back and checked it, sure enough, no surprise to you I'm sure, but it was "HF".  It was set to 50 by the PO, I never touched it, but turned it down to 15%.  I'll see how it goes in the future.  I'm sure I'll find it in the manual, but what does that control?  I was getting some crazy HF arcs if I touched the pedal too soon, blowing and dancing close to 1" gaps or so; is that the effect of higher setting?  And what is the confidence level that this is my problem?
Reply:Yes that dial controls HF intensity. The manual explains the adjustment fairly well from what I remember. You need just enough to get the arc started. A lot more and it starts to interfere with other electronics, lights and so on.As far as multiple grounds, this is a bit different than what is going on with a normal electrical system. The HF  from the machine is acting almost like a powerful radio signal transmitting thru the air. By "grounding" the metal items you help to disrupt or dissipate that signal by allowing the "static" like electricity to go to ground rather than into the electrical system. My explanation is probably way over simplified, but the pictogram in the manual explains it pretty well.As far as drilling thru the floor to ground, that's exactly what the one tech school had to do when they had HF interference issues and needed to ground all their new machines. They wre having major issues with the new machines messing up the new computers in the lab next door after they redid both class rooms a few years ago..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Being set at 50 percent was you problem! Good luck
Reply:Great, thanks.  I guess the test will be to replace the halogen bulbs and see what happens next time.Still not sure about what to do about grounding the power supply so that it can remain mobile.  The "ground" in the 220V 3 conductor plug is wired to the chassis.  And in order to remain mobile, the only thing I can think of is to run a 4 conductor cable/plug.  But if both ends tie to the same thing, no benefit.  Though I could sink a dedicated rod at the wall receptacle, seems like that would create a potential for potential difference an small current, the things that they talk about in general with multiple ground rods and electrical code.  I'm no electrician, but that's what I think I understand.Independent grounding for the table doesn't bother me so much.  I can easily pop a hole in the slab and (hopefully) get a few feet of ground rod into the substrate.  But I was thinking, it's slab on grade, and that grade is likely hard caliche, so might have some fun with that.
Reply:From a tech than hangs out on the miller forum"I've mentioned this before, MANY TIMES. simply tywrap the first 2' of tig and work cable together after leaving the machine. This solves the problem on EVERY transformer based machine. Inverter based machines only have the HF on to start (all materials) so like a tenth of a second so tywrapping may be unnecessary."http://www.millerwelds.com/resources...ight=groundingEd Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge