it works for my powcon inverter welder just fine.
i do use a 10hp balanced RPC to run it, i might add.
i might be able to get away with a balanced 7.5hp for short periods of time i would surmise .
i really didn't feel like a lot of experimentation with my selection of the RPC motor, i went heavy.
dependent on type of welder and amps you draw, you just may have similar results