Between 120 VAC and 230 VAC line voltage, the latter is significantly more efficient. To this one can also add the resistive losses from carrying double the amps over the house wiring for the same ...
https://hackaday.com/2021/06/07/intels-atx12vo-standard-a-study-in-increasing-computer-power-supply-efficiency/
The theory behind the "strange" voltage numbers like 277v and 208v stem from the way the sine wave of the power produces useful voltages which are approximately the cubed root of the peak voltage. In short, 208, 220, 240 all the same as far as your welder is concerned.
https://www.quora.com/What-is-the-difference-of-208-volts-220-volts-230-volts-240-volts-and-250-volts
How do you get 208 voltage? The formula is volts times the square root of 3, which happens to be rounded off to 1.732. For 2 lines each carrying 120 volts, the calculation for this is 120 volts times 1.732, and the result is rounded up to 208 volts. That's why we call it a 208 volt three phase circuit, or a 208 volt 3 phase line. In respect to ...
https://www.thermalcorporation.com/208-volts-is-a-weird-voltage-where-did-it-come-from
it usually means depending on the terminal wiring connection that the motor will operate satisfactorily at either 208 or 230 volts. This usually means the motor is 3 Phase so you will need to know if you have a 3 Phase service if you are going to operate the motor
https://www.quora.com/What-does-230-208-voltage-mean
doc for "208 230 460 volt meaning".(Page 1 of about 18 results)