On page 3 it states that there are 10 voltage steps. Each of the three primary windings only has 4 tapping points, and yet the machine has 10 steps, so there must be some asymmetrical switching going on in the rotary switch.
( I learned this in post #26 of this thread:
Yes, the "off load" check of welding voltages means trigger pressed but not welding ( known as the Open Circuit Voltage OCV ). To get an accurate reading of the voltage across the arc during welding is difficult. Ideally, use a Digital Storage Oscilloscope ( DSO ) board with a slow timebase that...
www.mig-welding.co.uk
Those bridges join the "far" end of each of the three primary windings together, so that they have a common point. This would make it a Star ( also "Wye" or "Y" ) 3-phase configuration, which would be valid.
Surely if you delete the L2 and L3 links, as you marked in red, then those two primary coils, and the two sets of 4 moving switch contacts, will just be floating?
Eddie49 is right.
The scheme is correct, and mine is also correct in post no. 6.
It would be good to delete my previous two posts no.7 and no.9, since they are incorrect, so as not to confuse anyone.
Sorry for my mistake.