Basic Circuit Theory the PF, and the impedance in each phase of the A- connected load if the line voltage is 120V and (a)P1=-500W,P2=1300W;(b)P1=1300W,P2=500W 8 Fig. 1 1-26 shows a balanced three-phase three-wire system with positive phase sequence. Let V BC=120 260V andR =0.6Q2. If the total load(including wire resistance)draws 5k Va at PF=0. 8 lagging. Find(a) the total power lost in the resistance, and(b)v R R Fig. 11-26 For prob. 8 9 Fig. 11-27 shows a balanced three-phase three-wire circuit Letr =0 and v an=200 V Each phase of the load absorbs a complex power, Sp=2-jl kVA( i.e. Pp= 2kW, Qp=lk R R Fig. 11-27 For prob. 9 10 In the balanced three-phase system of Fig 11-26, let Z p=12+j5Q2 and 1 bB=20 A with phase sequence. If the source is operating with a power factor of 0.935, find(a)R, v and V AB; (b) the complex power supplied by the source DaLian Maritime UniversityBasic Circuit Theory Chpter11Problems the PF, and the impedance in each phase of the ∆ - connected load if the line voltage is 120V and (a) P1= - 500W, P =1300W; (b) P1=1300W, P =- 500W. 2 2 8 Fig. 11-26 shows a balanced three-phase three-wire system with positive phase sequence. Let =120 V and R = 0.6 . If the total load (including wire resistance) draws 5k VA at PF=0.8 lagging. Find (a) the total power lost in the resistance, and (b) . V BC • o ∠60 w Ω V an • - + C a b N c A B n V a n • V b n • V c n • R w R w R w Z p Z p Z p + − + − Fig. 11-26 For prob.8. 9 Fig. 11-27 shows a balanced three-phase three-wire circuit. Let R = 0 and =200 V. Each phase of the load absorbs a complex power, = 2 – j1 kVA ( i.e. P = 2kW, Q =- 1k VAR). If positive phase sequence is assumed, find , Z , and . w V an • o ∠60 − S P P P V bc • P I aA • - + Z C a b c A + B n V a n • V b n • V c n • R w R w R w p Z p Z p + − − Fig. 11-27 For prob.9. 10 In the balanced three-phase system of Fig. 11-26, let Z = 12+j5 P Ω and = 20 A with “ + ” phase sequence. If the source is operating with a power factor of 0.935, find (a) R , , and ; (b) the complex power supplied by the source. I bB • o ∠0 w V bn • V AB • DaLian Maritime University 2