Republic of the Philippines

ILOILO SCIENCE AND TECHNOLOGY UNIVERSITY

La Paz, Iloilo City

College of Engineering and Architecture
Electrical Engineering Department

Name: Ivan John A. Biton Date Performed: August 15, 2023

Course and Year: BSEE 2-A1 Date Submitted: August 22, 2023

EE 22 ELECTRICAL MACHINES 1
DC Machines (LAB)

ACTIVITY NO. 01
Introduction to DC Machines, DC Motors and Generators

Objectives
At the end of the activity, the student possesses the ability to determine the
fundamentals of DC machinery, DC motors and generators, the different parts, and
electrical diagrams.

Discussion 1: Commutation and armature construction of DC Machines

In DC machines, the armature may take the form of a coil structure that freely
spins on the supporting bearings.The armature's coils produce the working torque and
EMF.The armature is made up of two basic components: the armature core and the ar
mature winding.The armature core may be a robust, hollow, circular structure built of
lean silicon steel lamination with good permeability.Spaces are cut into the center's ou
tside perimeter to carry the armature winding.Copper wires make up the armature win
ding.The two types of armature winding, namely lap winding and wave winding, depe
nd on the end connections of the armature conductors.The machine's voltage and curr
ent ratings are determined by the type of winding. The number of parallel channels for
current to stream in the case of lap winding is equal to the number of machine shafts.
In contrast, there are exactly two parallel pathways when using wave winding. The
commutator is one of the critical parts of the DC machine. It is fundamentally
mechanical rectifier. It may be a round and hollow formed device and is made up of
copper. The external periphery of the commutator has V-shaped spaces to carry
commutator sections. Where, the commutator sections are copper bars embedded
within the openings. These fragments are insulated from each other by mica. The
commutator is mounted on the shaft of the DC machine on one side of the armature.
The armature conductors are associated to the commutator portions with the
assistance of copper hauls.
The commutator performs the following two major capacities:
• It converts the rotating current of the armature into unidirectional current within
the outside circuit with the assistance of brushes, and vice-versa.
• In a DC generator, it collects the current from the armature conductor. In a DC
motor, it supplies the current to the armature conductors.

Discussion 2: Differentiate the Schematic diagram and Wiring Diagram. Give

specific samples.
Schematic diagrams illustrate the structure and operation of an electrical circuit
but do not show how the wires are physically laid out. Additionally, it shows how
efficiently and consistently a circuit operates. Schematic diagrams are used for
analyzing or designing control circuits to show how the circuit operates, although
these graphs don't show how the equipment is physically arranged or wired in the real
world.

SCHEMATIC DIAGRAM

Wiring diagrams, in any case,you are able to determine the relative location of
the wires and the way they should all be arranged physically. You can also see how
the wires are connected and where they must be based on the schematic. In motor
control installations, this type of diagram is frequently used to show the physical
connections between all the devices in the framework and the conductor
terminations between them. The electrical coherence of a circuit is displayed using
these diagrams, which use graphics to distinguish components and connector lines.

WIRING DIAGRAM
Discussion 3: List of safety measures to be observed while performing electrical
works.
All electrical threats cannot be completely eliminated by a safe working
environment. Workers must also exercise safety while working. Workplace safety
practices aid employees in reducing their risk of harm or death from workplace risks.
On the off chance that they are repairing electrical circuits. Dealing with electrical
instruments and equipment, they should follow safe work procedures. The safety
precautions used in their workplaces should be extremely familiar to all workers.
They must be able to use specific controls that help keep them safe. They have to also
exercise sound judgment and common sense.
All of us must follow a few safe work practices, such as keeping a safe distance
from moist working environments and being aware of other dangers, in order to
control electrical risks. Additionally, using the proper wiring and connectors, using
tools and wearing PPE while working are all examples of safe practices.
De-energizing and grounding lines while working close to them are other safety
precautions to include when dealing with electricity. Make sure the electrical
equipment is in excellent condition as well.

Discussion 4: Common abbreviation used in Electrical Design and Installation.

ATS Automatic Transfer Switch NC Normally Closed

ATC Automatic Temperature Control NEC National Electrical Code
AWG American Wire Gauge NFPA National Fire Protection Association
BTU British Thermal Units NL Night Light
C Conduit NO Normally Open or Number
CB Critical Branch P Pole
C/B Circuit Breaker PNL Pane
CCT Circuit (also: CIR, CKT) PWR Power
CCTV Closed Circuit Television
CD Candela
CKT Circuit (also: CCT, CIR)
CLF Current Limiting Fuse
CPT Control Power Transformer
IMC Intermediate Metal Conduit
INT Interlock
KCMIL Thousand Circular Mils
KVA Kilovolt-Amperes
KVAR Kilovolt-Amperes Reactive
LFMC Liquid Tight Flexible Metal Conduit
LTG Lighting
LRA Lock Rotor Amps
MC Metal Clad Cable
MCB Main Circuit Breaker
MCC Motor Control Center
MCP Motor Circuit Protection
MI Mineral Insulated
MLO Main Lugs Only
MW MegawattTMCB Thermal Magnetic Circuit Breaker
UG Under Ground
UL Underwriters Laboratory
V Volt
VA Volt-Ampere
VFD Variable Frequency Drive
VT Voltage Transformer
W Watt or Wire
WH Water Heater
WP Weatherproof or Waterproof
XFMR Transformer

Discussion 5: Different type of DC motors and its equivalent circuit.

Direct current (DC) motors are widely used in the mechanical sector
nowadays. Because of their extensive utility, small and medium-sized motoring
applications, from mechanical technology to vehicles, typically use DC motors.
Due of the great variety of DC motors that are available. Different varieties of DC
motors are appropriate for various mechanical industry applications, including
different duties. Additionally, knowing the many types of DC motors will enable
us to comprehend their use in a variety of applications and choose which type
may be appropriate for our needs application.

There are 4 main types of DC motors:

1. Permanent Magnet DC Motors
The permanent magnet motor uses a permanent magnet to form field flux.
This type of DC motor gives great starting torque and has great speed direction,
but torque is constrained so they are ordinarily found on low horsepower
applications.

2. Shunt DC Motors
In shunt DC motors the field is associated in parallel (shunt) with the
armature windings. These motors offer great speed direction due to the fact that
the shunt field can be energized independently from the armature windings,
which too offers simplified reversing controls.
3. Compound DC Motors
Compound DC motors, like shunt DC motors, have a independently
energized shunt field. Compound DC motors have good starting torque but may
encounter control issues in variable speed drive applications.

4. Series DC Motors
In a series DC motor, the field is wound with a number of turns of a huge wire
carrying the complete armature current. Regularly, series DC motors make an
expansive sum of starting torque, but cannot regulate speed and can indeed be
damaged by running with no load. These restrictions mean that they are not a great
option for variable speed drive applications.

Between the 4 types of DC motors, the potential applications are various.

Each type of DC motor has its qualities and shortcomings. Understanding these
can assist us understand which types may be great for our application.

Discussion 6: Different type of DC generators and its equivalent circuit.

An electrical equipment called a DC generator converts mechanical energy
into electrical energy as its main function. It also operates on the idea that when a
conductor coil is turned in a magnetic field, a voltage is initiated.
Where a small amount of electricity is needed, DC generators are used as
convenient generators. As dynamos, they are used in electric shavers, remote-
control cars, and motorcycles. These generators are also utilized in arc welding, a
process that involves extremely high voltage drops and continuous current.
Understanding the various types of DC generators will help us comprehend how
 they are used for various applications and which type may be applicable to our
application.

1. Permanent Magnet DC Generators

This kind of generator utilizing permanent magnets for making the flux within the
magnetic circuit is known as the Permanent magnet DC generator and is the foremost
fundamental type of generator. There are an armature and one or numerous permanent
magnets placed around the armature. This type cannot supply much power due to the
design of the generator and does not utilize it in industry applications. Permanent
magnet DC generators are commonly utilized in small applications, the same as
dynamos in motorcycles.

2. Series wound generators

The field winding is in series with armature conductors in series-wound
generators. The current within the field coil is the same as the load and flows in
both. Field windings are outlined with few turns and utilize thick wires to have
low electrical resistance. The circuit diagram for this type is as follows:

3. Long Shunt Compound DC Generators

In long shunt compound DC generators, the shunt windings are parallel with
both series field and armature. The circuit diagram for this type is as below:

4. Short Shunt-Wound DC Generator

 In short type, an armature is parallel with the shunt field windings, as
appeared within the following figure:

5. Shunt Wound DC Generators

The field windings are associated to the armature conductors parallelly to
energize the generator. Field windings are the insulated current-carrying coils that
create the required magnetic field for the excitation of the generator. A shunt
generator energizes by residual magnetism in poles, and the field windings have the
same voltage as the terminals within the shunt-wound generator, whereas the actual
value of this voltage depends on the load and its speed. The circuit diagram for this
type is as follows:

Summary and Recommendation:

I was able to become more familiar with the concepts pertaining to the
commutator and armature construction of DC machines by working on the lab
activity. I now know that an armature is a structure made of coils that can freely
rotate on bearings, whereas a commutator is a crucial component of a DC
machine positioned on the shaft of the DC machine on one side of the armature.
In connection with this, I was able to provide a list of safety precautions that
should be taken when undertaking electrical work. We all understand that having
a safe workplace isn't enough to eliminate all electrical dangers; employees also
need to operate safely in order to reduce electrical risks. there are a few safe work
guidelines that everyone must follow. I was also able to become familiar with
some of the popular acronyms used in electrical design and installation. The
ability to recognize the fundamentals of DC is something the learner has attained
by the end of the activity. the various components, electrical schematics, and
machinery, including DC motors and generators.
 Finally, I was able to identify and classify the various DC motor and
generator kinds, as well as get familiar with their comparable circuits. A series
DC motor, which creates a magnetic field flux using a permanent magnet, is one
type of DC motor. Shunt DC motors, in which the field is connected in parallel
(shunt) with the armature windings, are another type of motor in which the field
is wound with a number of turns of a large wire carrying the entire armature
current. There are several types of DC generators, including permanent magnet,
shunt wound, series wound, long shunt compound, and short shunt compound.

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%20plan,connections%20between%20all%
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