The document discusses the history, construction, types, working principle, merits and demerits of DC motors. It traces the origins of DC motors back to Michael Faraday's work in the 1830s. It describes the key components of a DC motor including the field poles, frame, armature, commutator and brushes. It also discusses the different types of DC motors like shunt, series and compound motors. Finally, it provides the working principle and highlights the merits like high starting torque and speed control capabilities, and demerits such as high costs.

1. DC MOTOR

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

3. 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

4. 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.

5. 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)

6. • 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

7. TYPES OF DC MOTOR
• SHUNT MOTOR –
Shunt Motor in which the
field winding is connected
in parallel with the
armature

8. • SERIES
MOTOR- Series
Motor in which
the armature and
field winding are
connected in
series

9. • COMPOUND
MOTOR- This type of
motor has two field
winding, one of which is
c6nnected in parallel
with the armature and
other in series with it

10. 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

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