6
3.4) 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 ou-
tput 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:
STICK WELDING:
V OUT = 20 + 0.04 x I OUT
Es.: 22Vdc @ 50A
24Vdc @ 100A
28Vdc @ 200A etc.
DC TIG WELDING:
V OUT = 10 + 0.04 x I OUT
Es.:12Vdc @ 50A
14Vdc @ 100A
18Vdc@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 intermittent 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 ou-
tput current & output voltage and use correct resi-
stance value & power!
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