Working of dc motor. uses and type of dc motor. a proper project file

1. CHAIL
PUBLIC
SCHOOL
CHEMISTRY REPORT
On
Cold drink available in the
Market

2. Submitted By - Shubham Saklani
Submitted To - PushpRaj Sharma

3. CONTENT Page no.
CERTIFICATE 1
ACKNOWLEDGEMENT 2
AIM OF PROJECT 3
INTRODUCTION 4-5
THEORY 6-11
OBSERVATION 12
CONCLUSION
13
APPLICATIONS OF EMI
14
PRECAUTIONS
15
BIBLIOGRAPHY
16

4. This is to certify that ShubhamSaklani, a student of class XII
of Chail Public School has successfully completed the
project under the guidance of Mr.OmkarSharma During
the academic year 2019-20 in partial fulfillment of physics
practical examination conducted by CBSE, New Delhi.
Teacher’s Signature Principal’s Signature

5. I would like to sincerely and profusely thank my Physics teacher
Mr.Omkar Sharma, for his able guidance and support in
completing my project.
I would also like to extend my gratitude to the principal for
providing me all the facility that was required.
Last but not the least, I would extend my gratitude toward all
teaching and non teaching staff of Chail Public School and
toward my friends who has supported me to complete this
project.
Shubham Saklani

6. INTRODUCTION
A DC motor is any of a class of rotary electrical
machines that converts direct current electrical
energy into mechanical energy. The most common
types rely on the forces produced by magnetic fields.
Nearly all types of DC motors have some internal
mechanism, either electromechanical or electronic, to
periodically change the direction of current flow in
part of the motor.
DC motors were the first form of motor widely
used, as they could be powered from existing
direct-current lighting power distribution
systems. A DC motor's speed can be controlled
over a wide range, using either a variable supply

7. voltage or by changing the strength of current in
its field windings. Small DC motors are used in
tools, toys, and appliances. The universal motor
can operate on direct current but is a lightweight
brushed motor used for portable power tools and
appliances. Larger DC motors are currently used
in propulsion of electric vehicles, elevator and
hoists, and in drives for steel rolling mills. The
advent of power electronics has made
replacement of DC motors with AC motors
possible in many applications.

8. PRINCIPLE
A machine that converts DC electrical power into
mechanical power is known as a Direct Current
motor.
DC motor working is based on the principle that when
a current carrying conductor is placed in a magnetic
field, the conductor experiences a mechanical force.
The direction of this force is given by Fleming’s
left-hand rule and magnitude is given by;
F = BIL Newtons
According to Fleming’s left-hand rule when an

9. electric current passes through a coil in a magnetic
field, the magnetic force produces a torque that
turns the DC motor.
The direction of this force is perpendicular to both
the wire and the magnetic field.
WORKING OF DC MOTER
Consider a part of a multipolar DC motor as shown in
the figure below. When the terminals of the motor
are connected to an external source of DC supply:
the field magnets are excited developing
alternate North and South poles
thearmature conductors carry currents.

10. Save
Part of a Multi-polar DC Motor
All conductors under North-pole carry currents in
one direction while all the conductors under South-
pole carry currents in the opposite direction.
The armature conductors under N-pole carry
currents into the plane of the paper (denoted as ⊗in
the figure). And the conductors under S-pole carry
currents out of the plane of the paper (denoted as ⨀
in the figure).
Since each armature conductor is carrying current
and is placed in the magnetic field, a mechanical
force acts on it.
On applying Fleming’s left-hand rule, it is clear that
force on each conductor is tending to rotate the
armature in the anticlockwise direction. All these
forces add together to produce a driving torque

11. which sets the armature rotates.
When the conductor moves from one side of a brush
to the other, the current in that conductor is
reversed. At the same time, it comes under the
influence of the next pole which is of opposite
polarity. Consequently, the direction of the force on
the conductor remains the same.
It should be noted that the function of a
commutator in the motor is the same as in a
generator. By reversing current in each conductor as
it passes from one pole to another, it helps to develop
a continuous and unidirectional torque.

12. Types of DC Motor
A DC motor (direct current motor) has a lot of
applications in today’s field of engineering and
technology. From electric shavers to automobiles –
DC motors are everywhere. To cater to this wide
range of applications – different types of DC motors
are used depending on the application.
The types of DC motor include:
Permanent Magnet DC Motor (PMDC Motor)
Separately Excited DC Motor
Self Excited DC Motor
Shunt Wound DC Motor
Series Wound DC Motor
Compound Wound DC Motor
Short shunt DC Motor
Long shunt DC Motor
Differential Compound DC Motor

13. Uses of DC Motor
Applications of DC Motors
The main applications of the three types of direct
current motors are given below.
Series Motors
The series DC motors are used where high starting
torque is required, and variations in speed are
possible. For example – the series motors are used in
Traction system, Cranes, air compressors, Vacuum
Cleaner, Sewing machine, etc.
Shunt Motors
The shunt motors are used where constant speed is
required and starting conditions are not severe. The

14. various applications of DC shunt motor are in Lathe
Machines, Centrifugal Pumps, Fans, Blowers,
Conveyors, Lifts, Weaving Machine, Spinning
machines, etc.
Compound Motors
The compound motors are used where higher starting
torque and fairly constant speed is required. The
examples of usage of compound motors are in
Presses, Shears, Conveyors, Elevators, Rolling Mills,
Heavy Planners, etc.
The small DC machines whose ratings are in fractional
kilowatt are mainly used as control device such in
Techno generators for speed sensing and in Servo
motors for positioning and tracking.