241 17 Figure 9 For Questions 1510 For Questions 1516 In fig

24,1 17, Figure 9. For Questions 15,10 For Questions 15,16: In figure 9, the variable resistor Rr is adjusted util as much real power as possible is absorbed from the cireuit. 5. What is the value of of R (a) 17.9 (b) 241 (c) 482 (d) 300 (e) None of the above 16. How much real power is transferred to the resistor R (a) 37.5 W (b) 48.0 W (c)17.2 W (d) 234 W (e) None of the above For Questions 17,18 The magnitude of the phase voltage of an deal balanced 3-phase Y-connected source is 880 V(rms). The source has positive phase sequee The souroe is connected to a load through lines with impelance 4 +j4.5 /o The balanced 3-phase Y-connected load has impedance 63 +j51 /o- 17. Determine the line current I (a) 23.9/-2).1° A (rms) (b) 15.62-832° A (ms) (c) 7.78223.5 A (rms) (d) 10.1L-39.60 A (rms) (e) None of the above 18. Determine the line-to-line voltage Vca. (Note which phase is requested) (a) 1524130.00 V (rms) (b) 11324-325 V (rms) (c) 1263 -84-1° V (rms) (d) 1420.021494 V (ms) (e) None of the above

Solution

IN MAXIMUM POWER TRANSFER THEOREM

ZL=CONJUGATE OF ZS.

ZL=(24.1-j17.9) ohms.

15) RL=24.1 ohms.

16) POWER=(24.1-j17.9)*[(2.4<0*(24.1+j17.9))/(24.1+j17.9+24.1-j17.9)]^2.

POWER=(53.84+j39.99) watts.

real power=53.84 watts.

17) Vph=880 volts.

ZLINE=(4+j4.5) ohms.

ZLOAD=(63+j51) ohms.

IaA=[880<0/(4+j4.5+63+j51)]=10.1<-39.6 amps.

18) VAN=880<0 VOLTS.

VBN=880<+120 VOLTS.

VCN=880<-120 VOLTS.

VCA=VCN-VBN=880<-120-880<0=1524.2<30 VOLTS.