1. Three – Phase Power System

2. Three-Phase Power

3. Definitions 4 wires –3 “active” phases, A, B, C –1 “ground”, or “neutral” Color Code –Phase ARed –Phase BBlack –Phase CBlue –NeutralWhite or Gray

4. Balanced Three – Phase System

5. Phasor Diagram Positive Phase Sequence abc

6. Phasor Diagram Negative Phase Sequence acb

7. Delta-Connected Sources V line = V  Line Voltages V line V ab V bc V ca Phase Voltages V Φ V a V b V c

8. Currents for the Delta Connection Line Current I line Phase Current I Φ I line = √3I Φ

9. Y-Connected Sources Line Voltages V line V ab V bc V ca Phase Voltages V Φ V a V b V c V line = √3V Φ

10. Currents for the Y - Connection Line Current I line Phase Current I Φ Line Current = Phase Current ----I line = I Φ

11. Power in a Balanced Three – Phase System Total Power is equal to 3 times the power per phase!

12. Power in a Balanced Three – Phase System (Continued) For a Balanced Y – Connected System

13. For a Balanced Δ – Connected System,

14. Three-Phase Bridge Rectifier

15. Conduction Sequence

16. Average Output Voltage, V dc

17. rms Output Voltage

18. Diode Currents

19. Transformer Secondary Current

20. Instantaneous Output Voltage