example 15.3   
resistence of duct 0.016807ohms 
 voltage drop in duct 529.2V 
 current 31487.4A 
current density 52920.000000A/m^2 
short circuit current 89964.0A 
short current density 151200.000000A/m^2 
 power 47.608949MW 
power delivered to load 30.945817W 
 loss in duct 16.663132W 
efficiency is 0.650000 
maximum power delivered to load 34MW