Question

In a Submerged Arc Welding, the welding transformer is rated as 100 KVA at a constant secondary voltage of 40 V and the rated duty cycle is 60%. During welding operation, a welder uses 3000 Amps current. The total welding time if the are on time is 2 min is

• A. 2.4 min
• B. 3.6 min
• C. 1.2 min
• D. 4.8 min

Answer 1

The correct option is D 4.8 min

$P_r=100\text{KVA;}{V}_r=40V$

$\therefore I_r=\frac{100\times {10}^3}{40}=2500A$

$Now,I^{2}D=I_R{}^2{D}_r$

${3000}^2\times D={2500}^2\times 0.6$

$D=0.4167$

$\therefore$ Total welding time

$=\frac{\text{Arc on time}}{\text{Duty cycle}}=\frac{2}{0.4167}=4.8\text{min}$