Recent developments in design of arc welding generators

A DROOPING volt-ampere characteristic is required of an arc welding generator in order to overcome the instability of the arc due to its negative resistance characteristic. Where there are abrupt changes in the arc resistance, as in metallic arc welding, this requirement becomes complex and exacting. Other desirable design features are as follows: 1. Elimination of the external reactor sometimes used to smooth out current fluctuations. 2. Reflection of current impulses in the main circuit back i n t o the field to quicken field flux changes and thereby make the machine more responsive to changes in the external resistance. 3. Elimination of the exciter without resorting to the two-pole armature four-pole field structure. 4. Elimination of all regulating rheostats and switches without interfering with the desirable characteristics of the generator.