Square wave Welding?

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My experience with sine-wave configuration is with solar inverters – I’ve run my home on both square-wave and “true” wave power supplies, but I have no experience with welding that made the distinction between different sine-wave configurations.  While looking for a TIG/STICK welder, I came across several ads boasting a square wave welder.  How do welders act between the different sine-waves?
Reply:To ME anyway I see no difference at all....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Thanks for the info, zapster and 7A749!  Yes, that is a good perspective: thinking of it as the difference between analog and solid state machines gives me a better footing when trying to better understand just what I am getting into as I shop for a stick welder.  I suppose a square AC is closer to DC welding than the true 60/50HZ power – though, why AC is better than DC in some cases, and DC is better in other cases is beyond my understanding.  I need to get an AC/DC welder and start playing.
Reply:In AC welding a plain old sine wave 60HZ machine would loose its arc 120 times a second, then have to reestablish. Most "transformer" machines add an overrunning high voltage/high frequency circuit. This helps establish the arc, and prevent it from going out so often. Square wave power drops to zero and reestablishes voltage in reversed direction so quickly the arc doesn't go out. In aluminum welding, where "transformer" machines without "chopper technology" you are stuck at 50/50 AC balance. As the oxide on aluminum is not very conductive, it can be difficult to "fire" the workpiece negative arc. Ultimately this "half" of the cycle is weaker than EN. It makes the machine very sensitive to dirt or oxide contamination.
Reply:Originally Posted by Willie BIn AC welding a plain old sine wave 60HZ machine would loose its arc 120 times a second, then have to reestablish. Most "transformer" machines add an overrunning high voltage/high frequency circuit. This helps establish the arc, and prevent it from going out so often. Square wave power drops to zero and reestablishes voltage in reversed direction so quickly the arc doesn't go out. In aluminum welding, where "transformer" machines without "chopper technology" you are stuck at 50/50 AC balance. As the oxide on aluminum is not very conductive, it can be difficult to "fire" the workpiece negative arc. Ultimately this "half" of the cycle is weaker than EN. It makes the machine very sensitive to dirt or oxide contamination.
Reply:Originally Posted by Willie BIn AC welding a plain old sine wave 60HZ machine would loose its arc 120 times a second, then have to reestablish. Most "transformer" machines add an overrunning high voltage/high frequency circuit. This helps establish the arc, and prevent it from going out so often. Square wave power drops to zero and reestablishes voltage in reversed direction so quickly the arc doesn't go out. In aluminum welding, where "transformer" machines without "chopper technology" you are stuck at 50/50 AC balance. As the oxide on aluminum is not very conductive, it can be difficult to "fire" the workpiece negative arc. Ultimately this "half" of the cycle is weaker than EN. It makes the machine very sensitive to dirt or oxide contamination.
Reply:Originally Posted by DennisKGosh, I think I am actually learning something!  In a true sine, the off/on would be longer that a square cycle.  But then, why not weld with DC exclusively?
Reply:Originally Posted by MinnesotaDaveAC Chopper technology for aluminum? Maybe I'm missing something?
Reply:Well, I thank you folks for your responses.  I got much from this thread.  Funny how a different perspective can turn the lights on.Last edited by DennisK; 04-15-2014 at 01:22 AM.Reason: spelling
Reply:Originally Posted by DennisKThanks for the info, zapster and 7A749!  Yes, that is a good perspective: thinking of it as the difference between analog and solid state machines gives me a better footing when trying to better understand just what I am getting into as I shop for a stick welder.  I suppose a square AC is closer to DC welding than the true 60/50HZ power – though, why AC is better than DC in some cases, and DC is better in other cases is beyond my understanding.  I need to get an AC/DC welder and start playing.