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now, i can already feel the heat from the flaming i'll get..lol BUT, hear me out.. this is my theory.. i think i can DO this, but will actually end up just buying one anyway.. BUT, i'd like to get opinions on whether YOU guys think what i'll tell ya here is do-able. ok..now, i've given this some thought on both the good and not so good aspects of this.. i'll give you both..i think i could build TIG rig capable of high freq outputs for welding aluminum and exotics.. how? thru a simple motor freq drive.. power in = power out on transformers. transient waves and spikes also transfer in proportional ratios, therefore if a square wave power source was introduces to the transformers primary winding, a low voltage, high current square wave output will result. now, as you guys know (i'm still learning, as it's somewhat new to me..) is that the whole idea behind a square wave (as told to me be a miller rep, and my own reading) is for EN/EP pulse width control.. varying and manipulating the time that the electrode is positive or negative will affect the welding result.so, not onto the "eh" parts of it.. certain drives will not allow the PWM manipulation present in the machines with the smoothing adjusment.. i could program the controller to utilize whats called DC injection, which is primarily used as a braking voltage, but.. ya.. this is getting deep. loljust as well, the cost of a drive big enough to supply 50A at 240 V is like about $4000 or so!! another "eh".. now, granted.. i could build my own with "SCR"s out of a motor controller, and it would be cheap, reliable and work well, but that gets into the whole "just buy the darn thing" area now.. insread of wasting time on building a machine thats already in existance.. i guess what i'd like to know after presenting the deal is do YOU think it's possible to get good weld results if cost wasn't an issue and this contraption was made? thanks!! (oh, and like i said.. i'll end up just buying a good rig.. i just wanna know if it could be done!)http://kawispeed.com/ -moderator and tech deluxewww.myspace.com/trickortrack -cuz i have no life
Reply:WHY?Well go for it and see.Maybe you could desighn a new welding line weld it like you own it
Reply:Several problems with your conceptFor TIG, you want constant current, and these drives are not designed for continuous CC mode operationDC injection won't help, as you will need the output transformer, which will not pass the DC. Welding with a 240V source without the transformer will not be practical, as TIG arc voltage is generally less than 20V. Injecting DC on the output of the transformer will tend the core to saturation and dramatically affect the transfer function unless the transformer is carefull designed for this.The hardest part with inverters is current feedback and loop stability. With a traditional transformer-type supply, controlled magnetic coupling, magnetic saturation, or inductive ballasting (like a magnetic ballast for a fluorescent light fixture) were the most common current control methods. Later, SCR's came into play, but the current control was still done with relatively simple and stable electronic feedback (or open loop), and stabilized by the large inductances. Relatively much easier problem to make work and make reliable.
Reply:ahh.. you both bring good points.. i actually hadn't considered saturation time. Hmm.. very good point.. virtual rep points to ya.uh.. (thinkin..) hm... well, i wasn't planning on actaully welding with 240 V.. this would simply manipulate the power going into a buzzbux i've got that's dying to do some work.i would surmise after reviewing it in my head tho that the losses both in flux and in eddy corrent-generated CEMF would be astoomical, being thats it's a movable-core transformer.. it's te old skool sear craftsman type wit hthe vertically sliding handle..sounds like you'd understand the flux deviation in the core as well as i do.. maybe another welder xfmr is in order!! lol.. i am glad you brought up some reasons it WON'T work.. this is why it's theory!! but i also figured tat after i buy a nice, minty tig rig, that, good Lord forbid the thing blows up, ican at least make a backup if it's crunch time and i NEED a welding machine.http://kawispeed.com/ -moderator and tech deluxewww.myspace.com/trickortrack -cuz i have no life |
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发表于 2021-9-1 00:48:51