Abstract
The efficiency values of the wedding arc (the ratio of heat absorbed by the base metal to the electrically supplied arc energy) were measured using 'a certain electrode (B-17 of the Robe Seikosho, the diameter of the core wire is 4mm) under v-arious'conditions : different kinds of current (a. c. and d. c., straight and reverse polarity) different welding currents (100A, 120A and 160A), different arc voltages obtained by maintaining different arc lengths. The results (Fig. 8 and Table 1) which are quite reasonable from the theory of arc phenomena, show that the efficiency value decreases as the arc voltage increases, yet it is independent of the current employed.
Among the electrodes coated with calcium carbonate, barium carbonate, alumina and boric acid respectively, those which give higher arc voltage show lower efficiency values and it gives also lower efficency value for given electrode when the polarity of higher arc Voltage is used, e. i. BaCO3 coated electrode under straight polarity and Al2O3 coated electrodes under reverse polarity (Fig. 9) show low efficiency value.
