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Welding from a Listeroid/ST generator rig

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olNick:
Bruce,

Bit further on this, FWIW, my first shotgun repair attempt (simply replacing the IGBT's), lasted about 5 seconds before blowing up, since I did not check that I had pwm drive, before enabling the HV (SMPS-101 lessons here)

I bit the bullet, and read up to understand how inverters/SMPS work. Poking around I found that GDT had shorted/opened I don't remember.
Replacing that transformer brought back the PWM, and the thing started working again, with new transistors

The welder is/was quite advanced for a early 90's design, with a very high duty cycle. Specifically stated 8KVA generator minimum, my bad..
The "6KVA" chinese honda that did the damage, essentially almost stalled at that time...

anyway, I don't qualify for even 2nd group above, ha...
nick

BruceM:
olNick,
Bravo on that repair. 
I expect a 90's design with IGBT's would not be power factor correcting, so it would need a much higher rating on the generator head to cope.

Inverter-welders have always been at the cutting edge of power designs.  I can't imagine a more difficult power design application; high current arcing and shorts are normal. 

 


mikenash:
Fwiw we use a couple of $400 180A inverter welders at work (one of which belongs to me, personally) off of a Chinese generator and have done so for over a decade at the cost of just one welder, which was very second-hand at the time, anyway.  We use an 11kVA generator and it doesn't really notice when the load comes on - no real drop in revs or whatever.  I have been told that is the secret to looking after both generator and welder.  Our local hire company won't hire you anything smaller than about 15kW if you tell them you're welding - they say it "blows up" the generators sometimes too.   Cheers

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