Ignoramus8092 wrote:

Guy Macon "http://www.guymacon.com/" wrote:

You mention six secondary windings, but I only see 3 connections
to the transformer on your schematic. The schematic looks like one
of these:
http://www.ipes.ethz.ch/ipes/Thyrist.../e_ThyrB3.html

That's similar the schematic for the three phase rectifier firing
system that I have and am considering installing into my CyberTIG:

http://igor.chudov.com/tmp/firing/pcti-firing.jpg

..but the description (six secondaries, interphase transformer)
sounds more like one of these:
http://www.ipes.ethz.ch/ipes/Thyrist...ke/e_saug.html

Yes, that is what I have right now.

I am not sure whether this describes your Cyber Tig, , but I have
often seen see welder transformers that consist of a 3-phase wye
secondary (which may or may not bring the center tap out) and a
eperate 3-phase delta secondary, each driving 3 diodes or triggered
SCRs.

I do not think so, no, what describes my CyberTIG right now is

http://www.ipes.ethz.ch/ipes/Thyrist...ke/e_saug.html
http://igor.chudov.com/tmp/firing/6-phase.jpg

The the delta and wye are 60 degrees phase shifted from each
other. The advantage of this is that the rectifiers/SCRs send twice
as many pulses per cycle to the capacitor, lowering the ripple
amplitude, increasing the ripple frequency, and improving the power
factor -- which is the main reason for doing it in a welder.

Yes... You are correct...

It seems as though this PCTI firing system cannot be adapted to the
current 6 phase wiring. Rewiring is not a huge deal and can always be
reversed.

It seems to me that you are on the right track. I am currently
designing systems that are in the 50KW to 1MW range; I am doing the
embedded processing and precision analog bits, but one of my
coworkers is among the top names in power electronics. I will be
happy to run things past him if your current effort runs into a snag.
I don't think it will, though.

--
Guy Macon
"http://www.guymacon.com/"