Comparison between AC and DC Welding Machines

There are two types of electric currents used for welding process viz. AC and DC. There are many differences between the AC welding machine and the DC welding machine.

AC Welding Machine Vs DC Welding Machine

The following table compares and contrasts the different features of AC and DC welding machines −

AspectAC Welding MachineDC Welding Machine
CostAC welding machine is less expansive.DC welding machine is 2 to 3 times costlier than AC welding machine.
Size & WeightAC welding machine is smaller in size and light in weight.DC welding machine is larger in size and heavier in weight.
OperationThe AC welding machine is simple to operate.The operation of DC welding machine is more complicated.
MaintenanceMaintenance of AC welding machine is easier and less costly. It is because it have no moving parts.As DC welding machine has moving parts. Thus, its maintenance cost is higher.
SuitabilityAC welding machine is not suitable for joining non-ferrous metals.DC welding machine can be used for all types of metals.
ElectrodeThe bare electrodes cannot be used with the AC welding machines. Only specially designed coated electrodes are used.All types of electrodes, i.e., bare or coated, can be used with DC welding machine.
Welding of sheet metalsAC welding machine is not used for welding of sheet metals due to difficulty in starting the arc.DC welding machine can be used for all types of work because the starting of arc is easier.
Arc blowIn AC welding machines, the problem of arc blow can be easily controlled.In DC welding machine, the problem of arc blow is severe and difficult to control.
EfficiencyThe efficiency of AC welding machine is high about 80 to 85 %.The DC welding machine is less efficient (30 to 40%).
Operating CostThe operating cost of AC welding machine is low.DC welding machine has higher operating cost.
Power FactorThe power factor of AC welding machine is very low about 0.3 to 0.4.The DC welding machine has high power factor of about 0.6 to 0.7.

Updated on: 23-Feb-2022

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