1. LD COLLEGE OF ENGINEERING AHMEDABAD
DC MOTOR

2. Present By; NAME ENROLLMENT NO. RONIT PATEL 140280109084 SACHIN PATEL
SAGAR PATEL
SHREYA PATEL
VIDHIN PATEL

3. INDEX HISTORY & INTRODUCTION OF THE DC MOTOR WORKING OF DC MOTOR
CONSTRUCTION OF DC MOTOR
TYPES OF DC MOTOR
MERITS & DEMERITS OF DC MOTOR

4. Brief History of DC Motor
The history of DC Motor can be traced back to the 1830s,when Michael Faraday did extensive works on disc type of machine

5. INTRODUCTION OF DC MOTOR
A DC Motor is a machine which converts electrical energy into mechanical energy. It depends for its operation on the force which is known to exist on conductor carrying a current while situated in a magnetic field.

6. Working Principle Of DC MOTOR
Whenever a current carrying conductor is placed in a magnetic field, it experienced a force whose direction is given by Fleming’s Left Hand Rule.
It shows the field set up by the poles
It shows the conductor field due to flow of current in the conductor

7. Construction of DC MOTOR
FIELD POLES- The pole shoe acts as a support to the field coils and spread out the flux in the air gap and reduce the reluctance of magnetic field.
FRAME- The Frame is the stationary part of a machine in which poles, and rotor are stationed.
ARMATURE- The armature consist of core and winding. It is built up of thin lamination of low loss silicon steel(0.4 to 0.5)

8. Cont.
COMMUTATOR- A commutator converts alternating voltage to direct voltage. It is a cylindrical structure built up of segment made drawn copper.
BRUSHES- The use of brushes is made for machines designed for large current at low voltage.
ARMATURE WINDING- The winding must be designated with the most advantages utilization of the material in respect to weight and efficiency

9. Types of dc motors
The D.C motors are classified depending upon the way of connecting the field winding with the armature winding.
D.C motor
D.C compound motor
Long shunt
Short shunt
D.C series motor
D.C shunt motor

10. D.C series motor

11. D.C shunt motor

12. D.C compound motor
Long shunt motor
Short shunt motor

13. Characteristics of a DC Motor
Torque-Armature current(electrical) characteristic(T Vs Ia)
Speed-Armature current characteristic(N Vs Ia)

14. Characteristics of a DC Shunt Motor

15. Characteristics of a DC Series Motor

16. Characteristics of a DC Compound Motor
The compound motors are of two types namely the cumulative compound of differential compound motors.

17. DC Motor Applications:
Shunt motor application
printing machinery
Paper machines
Centrifugal and reciprocating pumps
Series motor application
Electric trains
Cranes
Hoists
Conveyers
Compound motor application
Elevators
Punches
Shears
planers

18. MERITS DEMERITS High starting torque
Speed control over a wide range, both below and above normal speed
Accurate seedless speed control
Quick starting, stopping
High initial cost
Increased operating and maintenance cost because of the commutator and brush gear

19. APPLICATIONS OF DC MOTORS
D.C. SHUNT MOTOR
LATHES , FANS, PUMPS DISC AND BAND SAW DRIVE REQUIRING MODERATE TORQUES.
D.C. SERIES MOTOR
ELECTRIC TRACTION, HIGH SPEED TOOLS
D.C. COMPOUND MOTOR
ROLLING MILLS AND OTHER LOADS REQUIRING LARGE MOMENTARY TORQUES.