HF start and electronics?

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Hey all -So I  have heard that HF start can cause damage to electronics.  I read it in a few places but do not have the sources available currently.  I really want to put a computer out in the garage so I can look things up while welding/building but I am uneasy considering that I've read that HF start can damage electronics.Is there any validity in this?  I have seen dozens of guys running modern cameras for video while welding.  I have a buddy with a CNC plasma table w/ a desktop computer mounted RIGHT on the table.  So... what gives?
Reply:It's not necessarily true that it "will" damage electronics, but more true that it *can*.Every once in a while, I get my garage door opener wigging out when I am TIG welding, only when the arc is having a hard time starting (and so when the high frequency starting is activated for a longer time.)  Usually, it just makes the garage door opener lights start flashing, and then the garage door opener must be power cycled to reset it so that it's functional again.  It's also rare, but at least once, the HF actually triggered the garage door to open!  A garage door closing unexpectedly could be a safety hazard.There are ways you can supposedly cut down on HF emissions by grounding the case of the machine up to metallic objects (like a network of wires or mesh) in the room.  I haven't tried that, it's just not a big enough of a problem.  I don't know whether it only helps prevents the HF from escaping beyond the grounded objects.Oh, my cell phone SIM card did bite the dust (started getting random errors) and I can't help but think it could have been caused by HF.  Now I will try to set it to the side (a few feet away) when I weld rather than have it in my pocket.  I've noticed the signal (number of "bars" reception) being affected by the HF, for example it can lose its signal.  So, I think it's definitely possible it can damage electronics, but may or may not actually happen.One thing to keep in mind is that electromagnetic energy dissipates with the cube of distance.  So the potentially interfering or damaging power levels will falls off really fast as you get each foot away from the transmitting source - especially for those first few feet.If you have a computer in the same room as the welder, I'd try and not put it right next to the welding machine or the welding leads.  Put it at the other end of the room if possible, so the electromagnetic waves aren't as powerful.  Also, be aware that the source of the electromagnetic waves may more be the welding leads themselves (especially if you have long ones coiled up) than the machine box.Last edited by jakeru; 04-21-2012 at 12:34 PM.
Reply:Many of the air plasma systems today do not use high frequency for starting. none of the Hypertherm Powermax units use HF.Jim Colt Originally Posted by Jon KHey all -So I  have heard that HF start can cause damage to electronics.  I read it in a few places but do not have the sources available currently.  I really want to put a computer out in the garage so I can look things up while welding/building but I am uneasy considering that I've read that HF start can damage electronics.Is there any validity in this?  I have seen dozens of guys running modern cameras for video while welding.  I have a buddy with a CNC plasma table w/ a desktop computer mounted RIGHT on the table.  So... what gives?
Reply:I personally have not had any problems with electronics ever since I sold off all my transformer tigs with points.Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:the Problem with HF is the stray RF it emits.  The single best way to deal with this is a GOOD ground.  this is not the ground that you run from your machine to the work piece (though that needs to be good too, any resistance does cause an issue).  and teh ground that is running with all the AC wiring in your shop doesnt count, that could be really long and the number of connections adds to the resistance. I know some will say what I am about to tell you is way over kill, some might not say it is enough but take it under submission:Here is what I do.  just out side my garage i drove 3 8' ground rods, then soldered 1/2' thin wall copper pipe over each end and connected them all together using 1/2" copper pipe and fittings soldered together.  Then I run a 3 wide copper strap (20 gauge) into the garage. the strap is soldered to the 1/2' copper pipe.  The strap then runs up the wall and to the ground bars on my work bench, and radio cabinet.  now because it is impratical to solder the strap to the copper buss bars, a put some DeOxit electrical cleaner/enhance at each connections (come in a little tube but way worth it).  then from each buss bar I run low impeadence copper braid to each item I want grounded, never daisy chain (run ground from one piece of equipment to the next and then the last one to ground.  each piece of equipment get its own run to ground, it never has to go thru something else; this reduces what is called a ground loop). I also run some #4 ground wire to my sub panel in the garage.  I treat my welder just the same as  I do my radio equipment, I ground to the chassis of the welder, I also run a seperate ground to the welding table.  The idea behind all of this is I want to give the stray RF a low impeadence path to ground, I want it gone!  also I ground my air compressor and any other power tools in the same fashion.  Now I realize this take time and money, but I have doe also most all of this by visitinghte scrap yard often, I am amazed at what is being scrapped!  I buy sheets of copper and rip then down to make the strap.your will never know if your ground system is working unless you don't have a good one!I have different sensitive test equipment for working on electronics,(spectrum analyzers, oscopes, signal generators, etc, and lots of radios and associated parts, as well as computers and the LAN switches for my house all out in the garage,  I cant have any thing emiting stray RF, it cause problems and gets into everything else not good!also if you cant drive a ground rod system, then try diggins a trench about 12' deep and as long as pratical and lay 1/2" copper pipe then tie the ground system to that.  that works too.ok hope this helps,  oh and make sure you ground your computer too
Reply:Haven't broken any electronics with my HF start yet, but it does make my battery tenders freak out (charge light starts flashing like it's topping off) and my computer wireless connection in the house 30 feet away gets interrupted (weak signal to start with.)
Reply:Digging a ditch 12' deep and as long as "pratical" seems a little more difficult than driving a ground rod into the ground.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:Originally Posted by SundownIIIDigging a ditch 12' deep and as long as "pratical" seems a little more difficult than driving a ground rod into the ground.
Reply:Originally Posted by shovelonI personally have not had any problems with electronics ever since I sold off all my transformer tigs with points.
Reply:Go to Millers web site and look up the owners manual to any syncrowave tig welder.Inside is a very good diagram on how to ground a work space. The very least to do. Drive a ground rod next to the welder. one cable or strap to the case of the welder, one to your work table. one to any conduits near the welder. Any more will depend on if you have a wood or metal building.Cutting machines with HF start don't have problems because they have a very good grounding system. The valid reason for the trench is shallow soil. bed rock or boulders under the dirt.makes it impossible to drive a rod. Caution before driving a rod, make sure there aren't any utilities below.
Reply:ccawgc tnx for answering the trench issue.  the ditch is the alternative to hard pan problems.  to really get a good idea on a good ground system trying googleling RF ground systems, or radio ground systems.  I was talking to a friend of mine to other day he told me about a tower base that he had pour for a comm site.  it was something like 40 cubic yards  and all the rebar had been cad welded, over 4000 cad shots!  In communication sites problems add up quickly so poor connections can not be tolerated even if it is just rebar barley touching it causes problems.  I know this is over kill for our welding but the way I look at is, I have enough to do just fixing the things I want to work on, I dont need more thing to cause me a head ache.  Good luck,  keep your runs short!
Reply:The single best way to deal with this is a GOOD ground.