In the earlier AIG TIG 200P thread here, I posted some testing I did with a good AC/DC current probe and an oscilloscope on my budget welder. The point of the testing was to see what current it 'really' puts out when the Amps knob is set, then I got a few images of the current waveforms to workout the AC frequency in AC TIG mode, and see if it was square-wave AC output or something else. It did show a couple of interesting things (to tech nerds like me anyway).

This thread is kind of related to that one, in that I just repeated my current tests and waveform recording on a high end machine belonging to a good friend to see how it 'compared'.
There isn't any agenda other than it's nice to see what a higher cost purely digital controlled machine looks like in this way, and share it with anyone interested.

What started out my interest in the 'current output verses the machine setting', was a suspicion that my budget machine was a fair bit higher than it said.
This machine however, is very very close to what the control setting says, so close in fact I'm not prepared to argue one way or the other as it's lower in apparent error than the claimed accuracy of my borrowed current probe (a Tektronics A622)

Output current measured verses what was selected on the welders digital display.
Metalmaster_215_Elite_DC_TIG_output_verses_selected.jpg

A selection of waveforms captured in both DC and AC TIG modes below. In AC TIG all the 215 Elites special waveforms were captured towards the end.

DC TIG @ 80Amps - Oscilloscope trace is 50A per division on the vertical axis. We can see about the right current on the right hand side trace image, with an amount of ripple on top.
The left trace is a detailed view of the ripple. It shows about 8 Amps of ripple at 46Khz. I think I can deduce that the front-end inverter of the welder runs at 46Khz from this...
MM_DC_80A.jpg MM_80A_DC_ripple-trace_8Amps P-P.jpg

DC TIG Pulse mode at 50% duty cycle and 1 pulse per second. Very accurate. The right hand image shows a detailed view of a pulse transition. Looks very well controlled to me.
MM_80A_Pulse-On_50%.jpg MM_80A_DC_pulse-edge_transition.jpg

AC TIG - 60Hz AC - 30% AC Balance (normal balance on that machine). Middle image shows 10% AC Balance. The right hand image shows 50% AC Balance.
MM_80A_AC_60Hz_30%_Bal.jpg MM_80A_AC_60Hz_10%_Bal.jpg MM_80A_AC_60Hz_50%_Bal.jpg

AC TIG - 120Hz & 250Hz -30% AC Balance
MM_80A_AC_120Hz_30%_Bal.jpg MM_80A_250Hz_AC.jpg

Detailed view of 250Hz...
MM_80A_250Hz_AC_narrow_view.jpg


AC TIG 120Hz AC - Pulse mode at 10Hz.
MM_80A_120Hz_AC_Pulse-10Hz.jpg

Now the fun specialty stuff that a budget machine will never do...

AC TIG 80A at 60Hz AC - with AC+DC HYBRID Wave Mode - You can see here a small negative DC current offset between AC pulses.
MM_80A_60Hz_AC_in_AC+DC_Hybrid_wave.jpg



AC TIG 80A at 60Hz AC - with Soft Square Wave mode
MM_80A_60Hz_AC_Soft-Square_wave.jpg

AC TIG 80A at 60Hz AC - with Triangle Wave mode
MM_80A_60Hz_AC_Triangle_wave.jpg

AC TIG 80A at 60Hz AC - with Sine Wave mode
MM_80A_60Hz_AC_Sinewave.jpg

I'm out of time tonight. See what you guys make of that. I didn't see any HF bursts during transitions in the special waveforms, but they waveforms seem to cut through the zero current transitions very fast by design (I guess).
Attached Images




Read the full thread at metalworkforums.com...