An experimental power source for spot welding is designed to deliver current as a ramp function of\ntime: I = 100,000 t, where I = amp and t = sec. At
An experimental power source for spot welding is designed to deliver current as a ramp function of
\r\ntime: I = 100,000 t, where I = amp and t = sec. At the end of the power-on time, the current is
\r\nstopped abruptly. The sheet metal being spot welded is low carbon steel whose unit melting energy
\r\n= 10 J/mm3. The resistance R = 85 micro-ohms. The desired weld nugget diameter = 4 mm and
\r\nthickness = 2 mm (assume a disc-shaped nugget). It is assumed that 1/4 of the energy generated
\r\nfrom the power source will be used to form the weld nugget. Determine the power-on time the
\r\ncurrent must be applied in order to perform this spot-welding operation.
\r\n