DC Motor Analysis and Control

This assignment delves into the analysis and control of DC motors, specifically focusing on series wound motors. It examines the fundamental principles of motor operation, applying Fleming's left-hand rule to understand magnetic field interactions. The assignment further explores speed regulation challenges in series wound motors and proposes solutions using pulse-width modulation (PWM) techniques for precise speed control.

Competency Demonstration Report
Career Episode 1

CE 1.1 Project Information
Name of the project: Study of principles of operation of series wound DC motor model
Location of the project: Faridabad, Haryana
Project Duration: June-December 2008
Organization: YMCA University of Science and Technology
Role and Designation during the time: Electrical Engineer
CE 1.2 Project Background
CE 1.2.1 Characteristics of the project
I had taken this project work to study the principles of operation of series wound DC
motor model. The motor is used to convert electrical energy to the mechanical energy. The
standard operation of the motor is dependent on easy electromagnetic law which assured that
magnetic field is being formed about the current carrying conductor. It interacts with exterior
field, and then there is creation of rotational motion. The operating performance of the series DC
motor is implicated by use of the mathematical models. Those models share inputs of current as
well as voltage to the automatic output of motor such as torque and also speed.
CE 1.2.2 Objectives developed for the project
Following are the objectives of this particular project work:
 To study the principles of operation of series wound DC motor model
 To determine the voltage and current of series DC motor

 To analyze the working principle of DC motor
CE 1.2.3 My area of work
I had concerned about assembly of series DC motor. It consists of some essential
components such as the field winding; rotor holds of the armature conductors, brush segments
that are attached to the DC motor. I had determined the application of series wound motor as it
delivers higher torque. I had analyzed the applications of the motor into industrial nature. I had
determined that the principle of operation of electrical motors is based on contact of two
magnetic fields. Firstly, the magnetic field is produced by motionless part of motor and secondly
the magnetic field is created by revolving part.
CE 1.2.4 Project Group
I had undertaken this development under the leadership of my guide Mr Nitin Goyal. In
this project, my guide has provided me full support to understand the principles of operation of
series wound DC motor model using the mathematical model. Those are related to inputs of
current as well as voltage to the mechanical output of motor, torque and speed.

Dr. Dinesh Kumar
(Vice Chancellor)
Mr. Ashok Arora
(Dean of the Department)
Mr. Nitin Goyal
(Guide and Instructor)
Ruchi Verma
(Electrical Engineer)
Figure 1: People involved in the project
CE 1.2.5 My responsibilities throughout the project
I had concerned in studying the principles of motor, back EMF and DC motor as a load
to conduct the project work. I had analyzed DC-DC converter operation and switch mode buck
and boost converter circuits. I had evaluated the electrical systems, components and also
applications by design and conduct of research problems. I had developed the electrical products
by study the customer’s requirements and assembly of mathematical models. I had assured the
quality of the electrical equipments and DC motor by designing of electrical testing methods and
capabilities of system.

CE 1.3 Distinctive Activity
CE 1.3.1 Comprehending the theory of the project
I had analyzed the development of series DC motor includes of current that carries
armature associated to delivery end throughout commutator as well as brushes. Armature is
being positioned among north south poles of an electromagnet. I had supplied of direct current
within the armature, and then the mechanical forces are acting on it because of electromagnetic
effects of the magnet. The field coils of the motor are being wound by means of few turning as of
the current passed throughout the field is termed as armature current. I had determined that the
wires are heavier as diameter is enlarged to offer smallest amount of electrical resistances to run
towards the fully armature current. The coils which run the motor are unaltered as the current all
through the field is higher to generate strong field for making of necessary torque. I had
calculated the voltage as well as current of series DC motor by use of following equation:
I had determined that E is the supply voltage and Itotal is the current that are provided to
the electrical port of DC series motor. The supply current is flowing throughout armature as well
as field conductor and calculated as: Itotal= Ise = Ia,
Where, Ise = series current keen on the field coil
Ia = armature current.
I had calculated the voltage of the DC motor as: E = Ea + IseRse + IaRse,
Where, Eb = back EMF,
Rse = series coil resistance,

Ra = armature resistance.
As, Ise = Ia, then, E = Eb+Ia (Ra+Rse), it is stated as the basic voltage equation of the series
wound the DC motor.
Figure 2: Diagram of Series wound DC motor
CE 1.3.2 Engineering knowledge and skills applied in the project
I had understood different operational modes which are existing into series wound DC
motor model and selecting of suitable operational mode. I had also understood the characteristics
of DC motor such as torque and speed curves with power curves. I had applied the knowledge of
electricity as well as electrical materials into my work. I had understood that the electrical motors
are operated with use of interaction among two magnetic fields.
CE 1.3.3 Accomplishment and task performed
I had chosen correct kind of DC motor for conducting this project work. Among various
motors, I had selected series wound DC motors for understanding its respective principles. I had
used of “Fleming’s left hand rule” in order to determine way of forces act on armature
conductors of the motor. I had utilized this physics law to produce magnetic field by the current

carries of conductor and same conductor is being put into external magnetic field. I had
determined that moving coil of wire consisted of a voltage when there is a change into magnetic
flux. When the magnetic forces are origin the armature to turn around then the voltage which are
shaped transversely windings into the armature, namely back EMF. At the time the DC motor is
at steady state, then the voltage is coordinated the supply voltage which are functional into the
motor.
CE 1.3.4 Identified issues and their solutions
1.3.4.1 Issues
I had not done detailed analysis on modelling of the series wound DC motor, therefore
selection of one particular DC motor model is critical. The information about the motor has
provided for no load conditions. When there is no power into DC motor, then there is no
armature current and therefore the voltage becomes equal to the armature voltage.
1.3.4.2 Solutions
I have to gain an considerate of the operating ideas of the series wound DC motor to
select a particular DC motor model. I had to understand the project details based on accelerating
the power as well as speed of the motor.
CE 1.3.5 Plan to produce creative and innovative work
I had realized that my study on selection of type of DC motor is critical, therefore I had
analyzed study on DC motor and series wound motor control with use of pulse width modulation
techniques. It is a creative work as this motor is used to control speed as well as reduce the
staring torque. I had used of short pulses for controlling the motor. Duration of the pulse is the
main factor that can control the speed of the motor. I had determined that DC series motor has

poor regulation of speed. When mechanical load is being additional to shaft, then the speediness
is reduced. Speed regulation is capability of a motor to convey its reduced speediness to its
unique value, the back EMF is calculated as: Eb= (PψZN)/60A, where N= reduction of speed N.
There is a reduction of back EMF and increase into net voltage E-Eb, then series current
is increased by: Ise = (E – Eb)/Ra+Rse. The assessment of series current becomes high which
likely to oversupply the magnetic core of field. The below figure shows that as the magnetic flux
links the coil is increased at lower rate as compared to an increased into current further than the
saturation regions.
Figure 3: Effect of load addition into DC series motor
CE 1.3.6 Collaborative work
I was focused on the timeline of the project to complete it on schedule time. After
completion of the project, I had shared the project report with my guide, Mr, Niton Goyal for
random check to ensure that everything is correct as per project requirements. On bi-weekly

basis, I had discussed the project progress with my project guide. I had prepared a fully fledged
project report and documentation on the project related components.
CE 1.4 Project Review
CE 1.4.1 Project Overview
I had understood the values of electrical motors which can operate with use of interaction
of two magnetic fields. I had also applied the knowledge on Fleming’s left hand rule to produce
magnetic field by current carrying conductor.
CE 1.4.2 My contribution to work
I had assembled details on the technical specifications of the development work and kept
working into the project report. I had reviewed the complete theory with the project researchers
to create a project plan to enhance that all project works are conducted within time.