(2)计算功率P(三种方法) ①P= UCos(p 220×492c0s26.50 I RI R =9680W U jxL -jXo ②P=12R1+L2R2 I1↓I =442×3+222×8 =9680w BP=UL, cos530+ULcos (-370) =9680w例题分析 （2）计算功率P（三种方法） ①P=UIcos =220×49.2cos26.5o =9680W ②P=I1 2R1+ I2 2R2 =442×3+ 222×8 =9680W ③P=UI1cos53o+UI2cos（-37o） =9680W R1 R2 jXL -jXC • U • I I1 • I2 •