1. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 1 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I 7 AC Power

2. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 2 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 7.1 Circuit for illustration of AC power

3. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 3 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 7.11 The complex power triangle S P av Q Z P 2 +Q 2 =V. I |S| = P av = VI cos Q =VIsin ~~ ~~ ~~

4. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 4 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 7.18 + ~ – R jX L + – V ~ S V ~ L ~ I S

5. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 5 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 7.19 Im Q= 119 VAR 60 ReP = 68.4 W

6. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 6 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 7.20 Power factor correction

7. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 7 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 7.22

8. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 8 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 7.23

9. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 9 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 7.38 Ideal transformer n 1 :n 2 or 1:N PrimarySecondary ++ __ V ~ 1 V ~ 2 ~ I 1 ~ I 2

10. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 10 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 7.39 Center-tapped transformer

11. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 11 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 7.40 Operation of an ideal transformer

12. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 12 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 7.41 Impedance reflection across a transformer

13. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 13 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 7.46 Balanced three-phase AC circuit

14. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 14 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 7.47 Positive, or abc, sequence for balanced three-phase voltages Im Re V ~ an V ~ bn V ~ cn

15. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 15 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 7.48 Balanced three-phase AC circuit (redrawn)

16. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 16 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 7.49 Delta-connected generators a + _ b c A delta-connected three-phase generator with line voltages V ab,V bc,V ca + _ ~ + _ _ + V ~ ab V ~ bc V ~ ca

17. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 17 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 7.52 Balanced wye generators with balanced delta load

18. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 18 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 7.56 Line voltage convention for residential circuits Hot Neutral + _ Hot _ + V ~ W = 0 0 (Neutral) V ~ B = 120 0 (Hot) V ~ R = 120180 (Hot) orV ~ R =–V ~ B ~ ~V ~ B V ~ R

19. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 19 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 7.64 Structure of an AC power distribution network