Hi Griff!
I seriously do not think that Larry has given a biased opinion on the characteristics of the Miller Dynasty at all!!! :) :) :)
In fact I know that it is not a biased opinion because it is the same opinion I have regarding the Dynasty and it's capabilities when welding Aluminum!!!
Why??? Because, back in the days when transformer rectifiers were still king when it came to GTAW, I had the privilege of being at the right place, and at the right time (at least in the USA) when the very first inverters were being marketed and sold here in the early Eighties... During htat time, I was working for one of the largest independent welding distributors in the greater New York Metro area ,and we were about to become the first to market the Pow Con inverter type power sources as well as the Linde Union Carbide inverters which were also just bout to enter the market as well... Of course as the Technical Sales Representative of the company, I had no idea how these types of power sources were designed or much less, how to diagnose and troubleshoot them if a problem came up after selling one of them to our many customers...
I was eventually sent to learn how to service both brands of inverter type power sources, and after working on approximately twenty different warranty repairs on both brands, my company sent me to learn more about the Miller and Lincoln brand versions of inverter type power sources which were a heck of a lot different than the types of inverters that are sold today by a long shot!!! The differences were like comparing a pinto with a Corvette, a Fiat with a Ferrari, a - well, you get the picture I hope! ;0
The inverters of today are far more reliable than what I had to work with back in those days, and they were nowhere near as advanced, or came with as many capabilities as the current models being offered by a variety of different manufacturers today... In fact, the inverters of back in the day could compare in performance with such power sources as the Miller Synchrowaves, or both the Lincoln and Linde/L-Tec equivalents which were pretty good in their time when welding aluminum and a P&H back in those days was a smooth as on could come besides a Synchrowave when it came to welding Aluminum... The early inverters simply couldn't sustain the same type of consistency when it came to performance compared to the transformer-rectifier power sources available in the market back then.
Actually, it was Westinghouse during that time whom was at the forefront of coming up with more efficient types of rectification designs for their transformer type power sources in the Seventies when they were coming out with SCR & some of the very first thyristor type rectifiers, and they were just about to come out with their own version of an inverter type power source also, but they instead decided to get out of their welding products business all together and scuttled that division which was a real shame because the reports on what they were just about ready to market was exciting back in those days!!! :( :( :(
Nowadays, everything has reversed completely to the point where even the mighty Synchrowaves which were the "Gold standard" so to speak when it came to the ideal type of power source design to choose if one were to weld Aluminum... The newer, more efficient, and greater capability inverters out in the commercial market are soooo much better than the older technology transformer-rectifier power sources which can now weld both in AC as well as DC output current, leaving all of the commercially available transformer-rectifier type power sources in the dust with respect to their better features and capabilities with welding Aluminum - PERIOD!!!
Worldwide, there are to brands that exemplify the state of the art, and they are Fronius of Germany and OTC Daihen of Japan, although ESAB is no slouch either... Over here in the USA there are the Miller, Lincoln, and ESAB also which is made in Florence, SC @ the very same plant which made the very first plasma cutters & welders, and all of the former Linde Union Carbide/L-Tec welding and cutting equipment until ESAB took over and we cannot exclude the Thermal Arc inverters which do produce excellent arc welding capabilities, yet are not as relaible in design ruggedness IMHO when compared to the Blue, Red and Yellow brands... There are also a few other smaller companies which produce specialty type inverter power sources designed fro welding also, and Pow Con/Cyclomatics no longer produces the inverter that broke hte market wide open back in the day! :(
Now I have not had the opportunity to diagnose or troubleshoot the Fronius or OTC Daihen power sources, but I've worked on all of the other power sources as well as welded with them to find out just what sort of features and capabilities were being offered by these newer technology inverter type welding power sources... IMHO, the best power sources for Aluminum are being offered by Miller with Thermal Arc and ESAB running neck and neck and unfortunately Lincoln falling back to the end of the line. This is based on capabilities and features...
However when it comes to reliability and consistency is concerned, the Miller surprisingly took first place followed by the Lincoln, then almost tied for secon place was ESAB, and finally Thermal Arc last in line with respect to reliability... I still think that the Thermal Arc machine is an excellent inverter power source, yet it is obviously not as rugged as the other brands and for use out in the field, it weighs heavily in the reliability factor... This is not just based on my opinion either!!! This is based on the opinions of many different service personnel who regularly work on these types of inverter type power sources and currently have performed more work on these brands than I have recently.
Being able to both customize the balance control far beyond the capability of the older synchrowaves as well as being able to customize the wave form way beyond the capability of what is described by some as squarewave output, yet really obsolete when compared to the true squarewave output capabilities of the dynasty inverters... Then there is the capability to change the frequency output and increasing it way beyond what high frequency could offer in conventional transformer-rectifiers without having to use an overlapping superimposed and separate high frequency current in order to stabilize the arc as it transitions between half cycles along with total control of a separate pulsing feature also is brilliant!!! One cannot do this with a transformer rectifier like the synchrowave, and don't even get me started on asymmetrical capabilities of the Dynasty 700 amp power source!!!
The asymmetrical type inverter power sources are sort of an equivalent to the older variable polarity customizable waveform pulse power sources which were developed by NASA to weld a bunch of critical Aluminum structures found in the Space Shuttle program, and we are now experiencing the results of their advanced technology research in the newer Miller power sources. Now there are some even more exotic power sources out there which are even more capable than what is commercially available at comparable prices, and their capabilities are truly awesome, yet they are indeed cost prohibitive in many applications and are primarily used in very intricate and sophisticated applications that cannot be achieved with lesser capable equipment.
So I can definitely say with some sort of confidence that the current inverter type power sources do offer capabilities that were only available in some of our imaginations back in the heady days of when Synchrowave 350's & 500's, Squarewave 355's?, the old P&H's, the 330 ABP's, the Heliarc 350's, the older Hobart models and some of the other transformer rectifier AC/DC Hi Frequency power sources I forgot to mention were still King!!! :) :) :) There's just no comparison when it comes to what one can do with these newer inverters when it comes to welding Aluminum as well as other metals also!!! :) :) :) They are better made these days, and their pricing has come down substantially also which is refreshing as well!!! :)
Respectfully,
Henry