Question

In a gas tungsten arc welding process under steady state condition, the input voltage and current are measured as 18 V and 160 A, respectively. Heat loss during creation of arc is 40% of the input power. Heat loss through convection and radiation from the workpiece is 800 W. The effective power (in W) utilized to melt the workpiece is \(\underline{\hspace{2cm}}\). [round off to nearest integer]

Hint:

Always subtract arc losses first, then subtract surface heat losses to get the net weld melting power.

Answer 1

Correct Answer: 926 - 930

Input electrical power: \[ P_{in} = VI = 18 \times 160 = 2880\ \text{W} \] Heat lost during arc formation (40%): \[ P_{arc\ loss} = 0.40 \times 2880 = 1152\ \text{W} \] Remaining power reaching workpiece: \[ P_{rem} = 2880 - 1152 = 1728\ \text{W} \] Heat lost to convection & radiation: \[ P_{conv+rad} = 800\ \text{W} \] Effective power for melting: \[ P_{eff} = 1728 - 800 = 928\ \text{W} \] Thus, the effective melting power is: \[ \boxed{926\text{ to }930\ \text{W}} \]