The document discusses the principle of rotating magnetic fields used in AC motors. It demonstrates how a rotating magnetic field is created by having two phases with magnetic poles that alternate between north and south, out of phase with each other. This causes the magnetic field to rotate, which can turn the motor shaft and produce torque. Reversing the direction of one phase reverses the direction of rotation of the magnetic field and the motor.

1. Rotating Magnetic Field
Principle of AC Motors

2. Phase 1

3. Phase 1
Positive Half Cycle
Negative Half Cycle
North
South
South
North

4. Phase 2
Positive Half Cycle
Negative Half Cycle
North South
NorthSouth

5. Phase 1
Phase 2
1 2 3 4 5 6 7 8 1

6. Phase 1
Phase 2
1
N
S

7. Phase 1
Phase 2
2
N
S
N
S

8. Phase 1
Phase 2
3
N
S

9. Phase 1
Phase 2
4
N
S
N
S

10. Phase 1
Phase 2
5
N
S

11. Phase 1
Phase 2
6
N
S
N
S

12. Phase 1
Phase 2
7
N
S

13. Phase 1
Phase 2
8
N
S
N
S

14. Phase 1
Phase 2
1
N
S

15. Phase 1
Phase 2
1
N
S

16. Phase 1
Phase 2
2

17. Phase 1
Phase 2
3
N
S

18. Phase 1
Phase 2
4

19. Phase 1
Phase 2
5
N
S

20. Phase 1
Phase 2
6

21. Phase 1
Phase 2
7
N
S

22. Phase 1
Phase 2
8

23. Phase 1
Phase 2
1
N
S

24. Phase 1
Phase 2
1
N
S

25. Phase 1
Phase 2
2

26. Phase 1
Phase 2
3
N
S

27. Phase 1
Phase 2
4

28. Phase 1
Phase 2
5
N
S

29. Phase 1
Phase 2
6

30. Phase 1
Phase 2
7
N
S

31. Phase 1
Phase 2
8

32. Phase 1
Phase 2
N
S
N
S
Synchronous Motor
Induction Motor

33. COMMENTS?

34. Reversing the direction
Of a 2 Phase Motor

35. Phase 2
N
S
1

36. Phase 2
2

37. Phase 2
N
S
3
Anti-Clockwise

38. Phase 2
N
S
1

39. Phase 2
N
S
2
N
S

40. Phase 2
N
S
3

41. Phase 2
N
S
1

42. Phase 2
2

43. Phase 2
N
S
3

44. Phase 2
N
S
3
Clockwise

45. COMMENTS?