To Invertec or not to Invertec

Kodiak,

I'm giving you my opinion free. And likely over priced at that.

If I'm not mistaken"Invertec" is simply Lincoln's cute buzz word for "inverter technology". I am electrically challenged. Therefore, I can't give you a technical definition of what an inverter is/does.

But, as I conceptualize it, an inverter converts (inverts) DC to AC or vice versa by means of diodes and doo-dads rather than by copper windings.

The good result is small size, light weight, low power consumption, impressive duty cycle, and a very smooth arc.

On the other hand, I've heard several people say that when an inverter machine fails they're often not repairable. At least not at a reasonable price.

I have a Miller Maxstar 140 inverter machine. Plus I have several transformer machines. The Maxstar is a damned lovable little guy. I bought it last. If I'd bought it first I quite possibly wouldn't have bought any of the other machines.

However, I have always assumed that my as yet unborn grandchildren - and perhaps THEIR descendants - will be welding with the transformer machines. Or at least scrapping 'em for copper. I will be surprised (or at least I would be if I were still around) if they'll be welding with the Maxstar inverter machine.

I trust Miller inverters more only because I've had good luck with one. Don't know about the "Proline". But I sure wouldn't pay $2500 for it!

V

Lets cut through the Marketing stuff - The inverter units create high frequency so the high frequency cores (lighter...cheaper...

At this high frequency the power into the inverter isn't increased just frequency. With the high frequency, rectification and filtering is much easier. Power is directly related to the area under the curve (of the waveform). High frequency types it is easier to generate poly (many) phases and then rectify their outputs for even nicer DC without filtering.

HF power supplies were first developed for airplanes and then migrated to brute power supplies. Printers first then large electronic machines. The ones I helped design used dozens of 1000 watt inverter DC supplies - 2v, 5v mostly. Mostly negative! We didn't have the space, weight limit or such for heavy iron.

In reverse, the Navy was working on 28 cycles. Dad doesn't have marrow in one arm as 28 dives deep to the core under a short. Arm across two terminals of high power

28 cycle. The Navy didn't mind very heavy cores - needed them anyway to hold the boat down in the water... The Navy saw the problems and shut down the research.

Martin

Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH, NRA Life NRA Second Amendment Task Force Charter Founder

Robert Ball wrote:

Martin,

But you didn't explain the doo-dads!

Vernon

Have no idea what you are asking for. Talked to my Dad tonight. Issues with his driving now. I think his state is worrying about his age or eyes.

Martin - tons of toys and doo-dads in the shop. Many linear supplies and a few switchers. One a 100 amp 5V that is scary to plug in as it went directly into a printer.

Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH, NRA Life NRA Second Amendment Task Force Charter Founder

Vern> Martin,

Thanks for all the info guys. I would guess that to convert to higher frequency, you would have to convert to DC first (rectification of the 220VAC line to

360VDC) This is done using diodes or a full wave bridge. Then you chop that at 100KHz with a switching power supply that uses a much smaller transformer but more semiconductors, either SCR's or transistors, and step down that voltage to a high current low voltage winding. Then Filtering of the output required for this type might be alot smaller as well.

As Vernon said, this results in a much smaller, and lower weight unit, but I imagine it's much more complex, less reliable, and a bitch to get repaired. I also imagine this technology would not be accessible in the larger welders, as it would be too expensive for hobbyists.

Lincoln is claiming they have this "MICRO-START" technology on their precision TIG series welders. They say it uses an alternative low power supply that back-fills the main supply and helps start the arc and maintain it more easily. This translates into shorter HF starts, less trackmarcs, without HOT-starting or HF re-engagement during rampdown on crater fill. Essentially making the machine easier to use, especially for less experienced operators.

They also had some other comparisons to Millers' Synchrowave series that made it look real good. Can you guys tell me if I'm falling for a bunch of marketing hype or is this Lincoln stuff really superior?

- ...Kodiak