Excellent response as usual Larry!!! ;)
However I'm still curious as to why "Makeithot" does'nt see, and the key words here are: "don't see a noticeable difference in the arc" while playing around with the dial... Now I have'nt serviced any of the newer ac/dc squarewave inverters as of late but, I have serviced many a Synchrowave or 330ABP's, Miller Goldstar's and many other brand name transformer rectifier/Highfrequency AC/DC, CC power sources, and I know that if you "play around with the dial" where the high frequency adjustment is, you will most definitely see a noticable difference in the arc and I don't mean in the etching effect that Larry was describing... I'm talking about the effect of the continuous delivery of high frequency which aids in maintaining the arc in all of the sinosudial wave type power sources that I worked on... Please let me attempt to elaborate...
That "Dial" Makeithot is describing is basically a knob connected to a potentiometer that's mounted behind the sheetmetal plate where the dial is painted on... It's the potentiometer that controls the amount and intensity of high frequency current that is stored in the Hi -Freq capacitor that's also part of this circuit...
As one adjusts the placement of the knob at different locations situated on the dial, the intensity/amount of hi-freq will vary accordingly, and the effect will be noticeable but not in the same way Larry describes because, I also agree with Larry that the Hi Freq does'nt actually cause the "Etching"/cleaning effect on aluminum... It's the waveform's depth & time into the negative half cycle that causes the cleaning action... The high frequency only maintains the arc from extinguishing itself as it passes in to the negative half cycle whereby with out it, the arc would die out!!! Lawrence is also correct in describing the proper reason for the need to adjust the high frequency intensity, and this is why I'm curious as to why Makeithot does'nt see a noticeable difference in the arc!
So if one does'nt move the position of the power source, and it's within the recommended distance from the circuit breaker/wall panel box, should the high frquency adjustment from let's say - 15 to 70 have any noticeable effect in the arc characteristics??? You can almost bet that it will if the components that make up the high frequency circuit are "all" working properly!!!
In other words, if there is no noticeable change in any of the arc characteristics when adjusting the intensity of the hi-freq then there might be something wrong with the potentiometer or another component within the high Frequency circuit, even the old hi-freq contact electrodes could be worn out or need to be properly adjusted in the gap because, too much hi-freq intensity does cause a very volitile arc that exhibits much inconsistensy in the plasma stream almost like a pulsing effect on the puddle as the shielding gas inconsistently ionizes at a very intense rate.
The opposite occurs in the arc characteristics when there is not enough Hi-freq intensity: The arc tends to sputter at an erratic rate like it's having a hard time keeping the arc on, and depositing alot of "black soot" due to the inconsistent shielding gas arc plasma ionization if it occurs at all!!!
So in conclusion and based on what little Makeithot describes as to what is actually going on as far as the arc characteristics are concerned, if he's not noticing any difference in the arc when adjusting the hi-freq intensity then there's something happening within the High frequency circuit that's NOT working properly!!! I'm also presuming that he's not doing these adjustments while simultaneously welding, correct??? ;) Also, if it's a squarewave inverter type, then it could be something else all together because I'm not familiar with their internal circuitry ;) :) :)
Respectfully,
Henry