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Homemade IGBT MIG welder with ATX PSU parts. [blown yet again][blown count: 5]
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Refrigerator:
The plot thickens...
Pulled the diodes apart and they're very different inside.
The diode closest resembling the original had a die of 5x7mm and was connected by four bond wires.
But the TO-247 diode was entirely different, it had a die of 6x6mm and was connected with a big copper tab bonded directly to the die.
So in terms of current handling the TO-247 diode should actually be the better choice because it not only has a bigger die (36mm2 vs 35mm2) but also the better connection to the die (copper tab vs four bond wires)
Also for a quick comparison, assuming he bond wires in the RJK5010 MOSFET and the aforementioned diode are the same then then it having four would mean that it can only handle about 80A.

But then again the TO-247 didoes aren't that great if they short out and die before any real current gets to go through them.

Meanwhile i had more of those TO-247 diodes arrive so i might test the reverse breakdown voltage on them.
Refrigerator:
Did a quick reverse breakdown test and the voltage is 35V at 135µA and 65V at 400µA.
That makes it a 30V diode, no wonder it blew, in a half bridge configuration this thing would see at least double the output voltage.
strawberry:
ESAB Arc251i uses current mode cotroller but they do not use this function by some reason. but rather relay on custom 30A semikron module (blows time to time).

sherman and similar chinese use sg3525 or tl494,  2..or more paralel IGBT in bridge configuration. even seen paralel output transformers.

without output inductor. if welding wires tangle/twist inductance will drop below minimum and overload IGBT
Refrigerator:

--- Quote from: strawberry on July 07, 2019, 02:20:41 pm ---ESAB Arc251i uses current mode cotroller but they do not use this function by some reason. but rather relay on custom 30A semikron module (blows time to time).

sherman and similar chinese use sg3525 or tl494,  2..or more paralel IGBT in bridge configuration. even seen paralel output transformers.

without output inductor. if welding wires tangle/twist inductance will drop below minimum and overload IGBT

--- End quote ---

Good thing that i put the inductor in then.

What about the rectifier diodes?
strawberry:
https://elektrotanya.com/esab_caddy_arc-251i_810-xxx.pdf/download.html#dl
rectifier 3pcs dual diode module (not popular brand)
Esab arc 251i only drawback is wimpy plastic case

KEMPPI mastertig 2200
controller protected and filtered I/O
discrete diodes dual TO-247
IGBT module
transformer ~4x U core
big heatsinks

Miller maxstar 200 SD
custom controller (bunch of OP and logic)
single custom integrated module semikron SKIIP (IGBT , 3F rectifier, tyristor, PFC)
DC link voltage 810VDC

Migatronic navigator 3000
controller ML4828IS
rectifier two pcs DSEI 2x101 06
IGBT bridge can be seen in picture under PCB (4pcs)

Sherman MIG 200
controller sg3525 and lot of LM324 and wires
Sherman MIG 261M/4R
no triger circuit protection (control borad VCC overvoltage can happen) , weak funktion switches prone to corosion
bunch of discrete IGBT
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