Difference Between AC and DC Welding:

The Difference between AC and DC welding is given in table below

Particulars DC Welding AC Welding
Equipment Motor-generator set or rectifier is required in case of availability of ac supply, otherwise oil engine-generator set is required. In case of availability of ac supply only a transformer is required. Transformer costs less and its maintenance cost is also low.
Prime cost Two to three times as compared to that of a transformer. Comparatively low.
Operating efficiency Low; consequently high cost of electrical energy. High (about 85%).
No-load voltage Low (safer). Frequently too high (dangerous).
No-load requirements Very high. Low (advantageous).
Power factor Comparatively higher. Low, requiring Capacitors for correction.
Arc blow Pronounced. Not so pronounced with ac (advantageous).
Electrodes Both bare (non-coated) and thus cheap electrodes can be used. Only coated electrodes—expensive ones.
Heating Uniform Not so uniform as in case of dc.
Connected load (cross-sectional area of conductors and fuses) Normal. Considerably higher because of low power factor.
Welding of non-ferrous metals Suitable. NA
Arc stability Higher. NA
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