A copper bare wire, stranded, size 4/0 AWG is being tested in a laboratory (free air test), where the ambient temperature is 30 C (86 F). It is assumed that the damage temperature for this wire is 200 C. According to the results of previous tests, a factor h = 28 W/(㎡ K) can be used for a simplified first-order approximation. Using the simplified model described in class: a. Determine what would be the cable's ampere rating (IN) for a rated temperature of 65 C and the given ambient temperature
b. Determine the cable's minimum damage current (Id)
c. Determine the rt=Ky of the wire (approximated damage curve)
d. Plot the approximated damage curve in a log-log scale
e. Plot the "exact" (Approximation 1) damage curve in the same graph and compare. For which current value the two curves are practically equal?
f. Determine and plot the second approximation for the damage curve (T-Ind27t=K',d). Compare the plots of all the three damage curves