Selco Genesis 2200 PMC, Repair Manual

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9.4) Static load
Use of grid load can speed up fault tracing and machine testing.
Just remember that a fixed power resistor applied to machine's
output is somewhat equivalent to a welding arc, but only inside
of a narrow output voltage range, whose center value can be
determined by the formula:
TIG DC WELDING:
V OUT ≈ 10 + 0.04 x I OUT
Es.: 12Vdc @ 50A
14Vdc @ 100A
18Vdc @ 200A etc.
STICK WELDING:
V OUT ≈ 20 + 0.04 x I OUT
Es.: 22Vdc @ 50A
24Vdc @ 100A
28Vdc @ 200A etc.
MIG/MAG WELDING:
V OUT ≈ 14 + 0.05 x I OUT
Es.: 16Vdc @ 50A
19Vdc @ 100A
24Vdc @ 200A etc.
If output voltage goes too much above or below the rated value,
the generator could either saturate or go into arc force or other
special features could be performed (such as anti-flashing): in
both cases real output current could be much different from
expected value and the generator could even show an intermit-
tent output power.
Grid load resistor's rated power is also important, 'cos a 24Vdc/
100A grid load produces 2400W to be dissipated by air cooling.
So, when using grid load, pay attention to both
output current & output voltage and use correct
resistance value & power!