1. DC MACHINES
15/11/2016

2. DC MACHINES
Stator
Field system; brushes
Rotor
Armature & commutator

3. IMAGES -

4. Types Separately excited Self excited Shunt Series Compound Long shunt
Cumulative
Differential
Short shunt

5. IMAGES – Sectional view

6. Starters

7. WINDING DIAGRAM - LAP

8. WINDING DIAGRAM – LAP…

9. WINDING DIAGRAM - WAVE

10. WINDING DIAGRAM – WAVE…

11. ARMATURE REACTION

12. ARMATURE REACTION…

13. ARMATURE REACTION…

14. ARMATURE REACTION…

15. ARMATURE REACTION…

16. COMMUTATION

17. COMMUTATION… 1 3 5 7 9 11 13 15 17 19 21 23 25 27 2 4 6 8 10 12 14 16 18 20 22 24 26 28 1 3 5 7 9 11 13 15 17 19 21 23 25 27 2 4 6 8 10 12 14 16 18 20 22 24 26 28 1 2 3 4

18. COMMUTATION… I
2I=Ia 1 2 3 4 2I
I-Ic
2I-Ic Ic

19. Factors Affecting Commutation
Resistance of Copper Carbon contacts
Resistance of coil being commutation
emf induced in short circuited coil