(i) The supply voltage of DC machine remains steady while that of AC machine is alternating from positive to negative.
(ii) DC welding machine has rotating parts inside while AC machine is static.
(iii) The voltage in AC is from main supply while that of DC is from petrol driven engine.
(iv) Troublesome magnetic field causing arc blow is eliminated in AC welding set during welding.
(v) The efficiency of AC welding machine is slightly greater than welding set of the same capacity
(vi) Slightly covered or base wire electrodes can be used in DC set while flux covered electrodes can only be used in AC machine.
