1. The Magnetic Field of Synchronous Machines: Slides to Complement Class Notes by Constantine J. Hatziadoniu

2. Stator Carries a 3-phase ac winding, Rotor carries a dc winding

3. Machine with Salient Poles

4. The Rotor is supplied via slip rings

5. One phase with concentrated winding: Flux distribution is rectangular

6. One-phase distributed winding: Flux space distribution is closer to sinusoidal

7. Three phase stator: positive sequence currents

8. Phase a is excited by a sinusoidal current: Air-gap field is a sinusoidal (space) distribution pulsating in time

9. Phase a field is a two-pole magnet; The magnetic axis passes through the middle (axis) of the winding

10. Phase b bi-polar field

11. Phase c bi-polar field

12. All three fields added in the air-gap: The resulting field is a rotating sinusoidal distribution

13. The combined field (dashed line) moving around the air gap

14. …Continued

15. Instances of the rotating field: Field rotates ones around the air-gap within a complete electric period

16. The winding arrangement of a four-pole machine

17. Phase a of the 4-pole machine: The spatial distribution varies twice in a full cycle

18. Phase b of the 4-pole machine

19. Phase c of the 4-pole machine

20. The three distributions shown for the 4-pole machine

21. Combined field is a rotating distribution

22. The 4-pole field rotates ½ times around in one electric period— the machine speed is reduced to half the speed of a 2-pole machine

23. The Rotor Field of the 4-pole machine

24. Rotor and Stator Fields rotate in step inside the airgap