DC machines

Faradays laws, Lenz law, Fleming's Right hand and Left hand rule, principle and working of DC Generator and motor, back EMF, types of DC motor, Torque equation of dc motor, characteristics of DC shunt and Series motors, speed control of DC Shunt motor, industrial applications of DC Shunt and DC series motor.

1. UNIT 2
SYLLABUS









Prepared by
Prof. P. V. Thokal
Department of Electrical Engineering,
Sanjivani College of Engineering
Kopargaon.

2. Unit 2 Introduction to DC Machines
DC Generator:- A machine which converts
Mechanical Energy into Electrical energy is
called as “Generator”







DC
Generator
Mechanical
Energy
Electrical
Energy

3. Working Principle

6. Fleming’s Right Hand Rule








Application:- DC Generators

7. Fleming’s Left Hand Rule









Application:- DC Motors

10. Practical DC Machine

11. D.C. machine construction

13. Construction Details(Parts) of DC
Generator and DC Motor
•Yoke
•Armature
•Pole Core and Pole shoe
•Field winding
•Armature winding
•Commutator
•Brushes
•Bearings

14. Yoke

15. Yoke (Outer body)

18. Armature of DC Motor

19. Armature

20. Armature

22. EMF equation of DC Generator

23. EMF equation continued…….

24. Lap and Wave winding
Wave winding Lap winding

25. Comparison between Lap and Wave
Winding

26. Working Principle of DC Motor
Principle: Whenever a current carrying conductor
is placed in a magnetic field it experience a
FORCE.

27. Back EMF

28. Back EMF…continued

29. Types of DC Motors

1. DC Shunt Motor

2. DC Series Motor

31. Torque Equation of DC Motor

32. DC Motor characteristics
1. DC Shunt Motor

33. 2. DC Series Motor

34. 3. DC Compound Motor charact.
Electrical Charact. Mechanical Charact.

35. Necessity of Starter
•Starter is not used to start the motor.
•Motor Can Start without Starter also.
•Then What is the necessity of Starter?
•We know that, V= Eb + IaRa but If N=0, then Eb=0
•Then We get, V= 0 + IaRa
•Therefore Ia = V/Ra. If rated Volt is 230V DC and Ra=
1Ω (Assume)
•Then Ia= 230/1 = 230 Amp. If Such a very high curren
t flows through Armature at the time of start it may bur
n armature wdg, may damage brushes etc.
•Therefore, Starter is used to limit the very high sta
rting current taken by the motor at the time of start
.

36. Three Point Starter for DC Shunt Motor

37. 3 Point starter

38. Speed Control of DC shunt motor

•1. Flux Control

39. • 2. Armature Voltage Control Method or R
heostatic Control

40. Industrial Applications

41. DC motor Applications