Voltage?

[David]

I've seen some machines using DC voltage and other use AC, what it the purpose of this and is there a transformer in the machines that automaticly convert between the two?


Thanks
David

[Mike Sherman]

David, this could turn into a very long a detailed answer if we are not careful. The short answer is that occasionally it is advantageous to use the AC sine wave when welding. The most common examples are when welding SMAW and you have serious arc blow, switching to AC will eliminate it. The other is when GTAW aluminum, the combination of the cleaning action (ionization) of the positive side of the sine wave and the penetration of the negative side make welding aluminum much easier. As to how the sine wave is rectified there are several ways to do that and I don't believe any of them are automatic. You must always flip the switch yourself. You would never want to change while you are actually welding. I hope this answers your questions satisfactorily and that I have not led you astray.

[Roger]

Cheapest way to make welder that plugs into outlet is, AC electricity from outlet to transformer that lowers voltage to what is safer and needed for welding with AC electricity out from welding machine for welding.
To change AC (alternating current) to DC (direct current) diodes are used. Diodes let electricity flow in one direction and resists flow in opposite direction. You can change 1/2 of AC synewave to DC or better for welding full synewave to DC. This results in pulsating DC. Capacitors and inductors are used to smooth out DC pulses for smoother better welding DC current.

Can generate DC electricity with DC generator.