I see. Glad that we agree then.
Absolutely. I think (being a newbie to welding etc) that at 50-50 cycle, the amount od reverse polarity is excessive and leads to overheating of tungsten electrodes, without any benefit. So it is good to set cleaning (epecrode positive) to less than 50% of cycle.
That's right.
I bought my welding machine for $9.99 on ebay:
I also have pulsing. My welder is actually quite fancy, except for not having AC. All digital, etc.
i
That one?
Didn't know about that, but looks like fun! Prost!
Nick from Munich/Bavaria
-- Motor Modelle // Engine Models http://www.motor-manufaktur.de DIY-DRO -> YADRO
That's the one ! Cheers.
Steve
But this might also mean, that we are equaly ignorant. I'm not a welding-pro.
I just had a look in my welding book (not that much about TIG power sources in there). It says, that you get a diode (when welding Al, but even with steel) due to the oxyde in the puddle. That is the reason for having a DC offset (when welding with AC). It is there to compensate the diode effect. The offset doesn't seem to be very high. From the diagram, I guess about 30%.
I know, that's the reason for the "washing machine"
Seems that pulsing is only used with DC. If you would use it with your H-bridge, you should have to switch polarity in sync with the pulses. Can you adjust the base current and the max current?
LOL! "Digital". You have thumb wheels with digits. But looking at the wire nest in that machine, is is damned analog.
Nick
-- Motor Modelle // Engine Models http://www.motor-manufaktur.de DIY-DRO -> YADRO
That, too, although this is less of an issue with squarewave.
Yes, I can, and I cannot see why pulsing cannot be used with an inverter.
Yes, I mean digital settings.
i
I am glad that I understood it correctly.
Try left clicking on the image. It works for my firefox and also mozilla, I think.
Agreed.
Yes, but also at any given moment only one half of the secondary is supplying current, although in AC mode these halves alternate.
i
Thanks. After reading your post, I finally understood what IGBT was about. And I tried to understand before, but your post explained it very nicely.
As far as I understand, homogeneous (equal in all respects) IGBTs can actually be paralleled. Mine are homogeneous and mounted on same heatsink, etc. At low levels of current (say under 50%) they could be unbalanced, but that's not a reason to worry. They do balance out at higher currents. At least that's how I understood things.
i
Nah... that isn't necessarily so. But it can be. Like Cindy Crawford says on that furniture commercial, "I only want to do what I'm passionate about." (Why, oh, WHY couldn't she be passionate about my body????)
If you truly LOVE what you're doing as a hobby, making it a vocation isn't all that bad. I did fireworks for a hobby for years, then decided to make a living doing it. It was the best career decision I ever made!
'Pends on what you expect of it.
LLoyd
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