Chapter 2, Problem 2.21P

Often, we encounter delta-connected loads such as that illustrated in Figure P2.21, in three-phase power distribution systems (which are treated in Section 5.7). If we only have access to the three terminals, a method for determining the resistances is to repeatedly short two terminals together and measure the resistance between the shorted terminals and the third terminal. Then, the resistances can be calculated from the three measurements Suppose that the measurements are Ras=12 $\Omega$ , Rbs=20 $\Omega$ , and Rcs=15 $\Omega$. c) Where Ras is the resistance between terminal a and the short between b and c, etc. Determine the values of Ra, Rb, and Rc. (Hint: You may find the equations easier to deal with if you work in terms of conductances rather than resistances Once the conductances are known, you can easily invert their values to find the resistances)

Figure P2.21