The same power ac motor is more expensive than the dc
Ac motor only has stator winding is copper wire! The rotor is cast aluminum bars! The cost is much lower! Simple process! Dc motor stator rotor is copper wire winding, and commutator. (commutator), it is copper. The process is complicated! Therefore same power dc motor is more expensive than ac motor!
Is the same power ac motor more expensive or more expensive? The price is of course the dc welder. But you welding, non-ferrous metal or welding have special requirements that you must use dc welding machine, because it has high no-load voltage. The arc easy. Wide range of welding current. Steady arc. The weld appearance, etc. If you weld a regular iron plate that's all you need to do with the ac welder.
Of course, dc is expensive, dc motor is much more complicated than the three-phase squirrel-cage ac motor.
