tig humming sound???

admin

I have a Lincoln PT 185. I have noticed a loud humming sound coming from the machine, right as the arc is struck. As I continue to weld, the hum goes away. It only last a couple seconds, then goes into the very faint hum of the normal higher pitch tig sound. Is this normal? I don't remember hearing it at my old shop, and have since noticed it after moving it. But it could have been happening all along, just never paid much attention to it. It seems to weld as normal, but never remember hearing the loud hum that disappears as I continue to weld. ???? Anybody know if this is normal and I am just freaking out over normal sounds? Thanks!
Reply:Does the machine have high frequency start?High freq makes it easier for the arc to make the initial connection, and once it is struck it goes away.  Some machines also make it an option to leave it on, it helps keep the arc stable with AC welding.Have we all gone mad?
Reply:Yes, it has high frequency start. It last just about two seconds after the arc is struck and then goes away. So I assume it is normal? Thanks for the quick response!
Reply:If it ain't broke, don't fix it! MM252 w/30AMM140 w/o AS w/SM100 w/CO2TA ArcMaster 185 TIG/StickTA 85 TIG/Stick LunchboxHobart (Miller) AirForce 625Hobart AirForce 250ciVictor O/A (bored)Lincoln Patriot AutoShade (freebie)45ACP for those stubborn jobs...
Reply:Ya, that sounds like high freq.  If you want to know for sure, take the torch and hold it to a metal object that is not connected to your ground cable in any way.  Then just step on the pedal and look at the high freq arc, the humming should continue as long as you hold the pedal down while the arc isnt striking.If your daring, hold it like you were going to weld on your fingernail and see what happens.  Just make sure you are not touching the ground, its acually a pretty neat trick.Have we all gone mad?