Basic EE Module 123

LEARNING MODULE SURIGAO STATE COLLEGE OF TECHNOLOGY
Module No. 1
COURSE INTRODUCTION
I. Topic: Course Introduction
II. Time Frame:2 hours
III. Introduction:
This course focuses on the environmental systems in buildings. Lecture discussions include
building electrical systems, natural and artificial lighting, and building telecommunications.
Reducing operational loads and integrating high performance energy systems into buildings
offers solutions towards achieving a sustainable and secure energy future. Engineers must
understand the interrelationship between a building and its subsystems and need sufficient
knowledge of building systems and design alternatives to recommend appropriate solutions
that suit the site, climate, building type, and occupants. They must coordinate the work of
the engineering disciplines that carry the sustainability concept forward through building
design, construction, commissioning, operation and, ultimately, demolition, recycling and
reuse.
In this section, we are going to name and define the electrical terminologies and give
examples in the real world scenario.
IV. Objectives:
At the end of the lessons the student should be able to:
1. Name and define common electrical terminology;

2. Give example of the electrical terminologies in the real world scenario.
V. Learning Activities
COMMON ELECTRICAL TERMINOLOGY
Alternating Current (AC) — An electric current that reverses its direction many times a
second at regular intervals.
Ammeter — An instrument for measuring the flow of electrical current in amperes.

Ammeters are always connected in series with the circuit to be tested.
Ampacity — The maximum amount of electric current a conductor or device can carry
before sustaining immediate or progressive deterioration.
Ampere-Hour (Ah) — A unit of measure for battery capacity. It is obtained by multiplying

the current (in amperes) by the time (in hours) during which current flows. For example, a
battery which provides 5 amperes for 20 hours is said to deliver 100 ampere - hours.
ES-141 ENGINEERING UTILITIES 1 (ARCH. MARLON C. SOLLOSO - ASSISTANT PROFESSOR III)

Ampere (A) — A unit of measure for the intensity of an electric current flowing in a circuit.
One ampere is equal to a current flow of one coulomb per second.
Apparent Power — Measured in volt-amperes (VA). Apparent power is the product of the
rms voltage and the rms current.
Armature — The movable part of a generator or motor. It is made up of conductors which

rotate through a magnetic field to provide voltage or force by electromagnetic induction. The
pivoted points in generator regulators are also called armatures.
Capacitance — The ability of a body to store an electrical charge. Measured in farads as

the ratio of the electric charge of the object (Q, measured in coulombs) to the voltage
across the object (V, measured in volts).
Capacitor — A device used to store an electric charge, consisting of one or more pairs of
conductors separated by an insulator. Commonly used for filtering out voltage spikes.
Circuit — A closed path in which electrons from a voltage or current source flow. Circuits
can be in series, parallel, or in any combination of the two.
Circuit Breaker — An automatic device for stopping the flow of current in an electric circuit.
To restore service, the circuit breaker must be reset (closed) after correcting the cause of
the overload or failure. Circuit breakers are used in conjunction with protective relays to
protect circuits from faults.
Conductor — Any material where electric current can flow freely. Conductive materials,
such as metals, have a relatively low resistance. Copper and aluminum wire are the most
common conductors.
Corona — A corona discharge is an electrical discharge brought on by the ionization of a

fluid such as air surrounding a conductor that is electrically charged. Spontaneous corona
discharges occur naturally in high-voltage systems unless care is taken to limit the electric
field strength.
Current (I) — The flow of an electric charge through a conductor. An electric current can be
compared to the flow of water in a pipe. Measured in amperes.
Cycle — The change in an alternating electrical sine wave from zero to a positive peak to
zero to a negative peak and back to zero. See Frequency.
Demand — The average value of power or related quantity over a specified period of time.
Dielectric constant — A quantity measuring the ability of a substance to store electrical

energy in an electric field.
Dielectric strength — The maximum electric field that a pure material can withstand under
ideal conditions without breaking down (i.e., without experiencing failure of its insulating
properties).

Diode — A semiconductor device with two terminals, typically allowing the flow of current in
one direction only. Diodes allow current to flow when the anode is positive in relation to the
cathode.
Direct Current (DC) — An electric current that flows in only one direction.
Electrolyte — Any substance which, in solution, is dissociated into ions and is thus made
capable of conducting an electrical current. The sulfuric acid - water solution in a storage
battery is an electrolyte.
Electromotive Force — (EMF) A difference in potential that tends to give rise to an electric
current. Measured in volts.
Electron — A tiny particle which rotates around the nucleus of an atom. It has a negative
charge of electricity.
Electron theory — The theory which explains the nature of electricity and the exchange of
"free" electrons between atoms of a conductor. It is also used as one theory to explain
direction of current flow in a circuit.
Farad — A unit of measure for capacitance. One farad is equal to one coulomb per volt.
Ferroresonance — (nonlinear resonance) a type of resonance in electric circuits which

occurs when a circuit containing a nonlinear inductance is fed from a source that has series
capacitance, and the circuit is subjected to a disturbance such as opening of a switch. It
can cause overvoltages and overcurrents in an electrical power system and can pose a risk
to transmission and distribution equipment and to operational personnel.
Frequency — The number of cycles per second. Measured in Hertz. If a current completes
one cycle per second, then the frequency is 1 Hz; 60 cycles per second equals 60 Hz.
Fuse — A circuit interrupting device consisting of a strip of wire that melts and breaks an
electric circuit if the current exceeds a safe level. To restore service, the fuse must be
replaced using a similar fuse with the same size and rating after correcting the cause of
failure.
Generator — A device which converts mechanical energy into electrical energy.
Ground — The reference point in an electrical circuit from which voltages are measured, a
common return path for electric current, or a direct physical connection to the Earth.
Ground Fault Circuit Interrupters (GFCI) — A device intended for the protection of
personnel that functions to de-energize a circuit or portion thereof within an established
period of time when a current to ground exceeds some predetermined value that is less
than that required to operate the overcurrent protective device of the supply circuit.
Henry — A unit of measure for inductance. If the rate of change of current in a circuit is one
ampere per second and the resulting electromotive force is one volt, then the inductance of

the circuit is one henry.
Hertz — A unit of measure for frequency.Replacing the earlier term of cycle per second
(cps).
Impedance — The measure of the opposition that a circuit presents to a current when a
voltage is applied. Impedance extends the concept of resistance to AC circuits, and
possesses both magnitude and phase, unlike resistance, which has only magnitude.
Inductance — The property of a conductor by which a change in current flowing through it

induces (creates) a voltage (electromotive force) in both the conductor itself (self-
inductance) and in any nearby conductors (mutual inductance). Measured in henry (H).
Inductor — A coil of wire wrapped around an iron core. The inductance is directly
proportional to the number of turns in the coil.
Insulator — Any material where electric current does not flow freely. Insulative materials,
such as glass, rubber, air, and many plastics have a relatively high resistance. Insulators
protect equipment and life from electric shock.
Inverter — An apparatus that converts direct current into alternating current.
Kilowatt-hour (kWh) — The product of power in kW and time in hours. Equal to 1000
Watt-hours. For example, if a 100W light bulb is used for 4 hours, 0.4kWhs of energy will be
used (100W x 1kW/ 1000 Watts x 4 hours). Electrical energy is sold in units of kWh.
Kilowatt-hour Meter — A device used to measure electrical energy use.
Kilowatt (kW) — Equal to 1000 watts.
Load — Anything which consumes electrical energy, such as lights, transformers, heaters
and electric motors.
Load Rejection — The condition in which there is a sudden load loss in the system which
causes the generating equipment to be over-frequency. A load rejection test confirms that
the system can withstand a sudden loss of load and return to normal operating conditions
using its governor. Load banks are normally used for these tests as part of the
commissioning process for electrical power systems.
Mutual Induction — Occurs when changing current in one coil induces voltage in a second
coil.
Ohm — (Ω) A unit of measure of resistance. One ohm is equivalent to the resistance in a
circuit transmitting a current of one ampere when subjected to a potential difference of one
volt.
Ohm's Law — The mathematical equation that explains the relationship between current,
voltage, and resistance (V=IR).

Ohmmeter — An instrument for measuring the resistance in ohms of an electrical circuit.
Open Circuit — An open or open circuit occurs when a circuit is broken, such as by a
broken wire or open switch, interrupting the flow of current through the circuit. It is
analogous to a closed valve in a water system.
Parallel Circuit — A circuit in which there are multiple paths for electricity to flow. Each
load connected in a separate path receives the full circuit voltage, and the total circuit
current is equal to the sum of the individual branch currents.
Piezoelectricity — Electric polarization in a substance (especially certain crystals) resulting

from the application of mechanical stress (pressure).
Polarity — A collective term applied to the positive (+) and negative ( - ) ends of a magnet
or electrical mechanism such as a coil or battery.
Power — The rate at which electrical energy is transferred by an electric circuit. Measured
in Watts.
Power Factor — The ratio of the actual electrical power dissipated by an AC circuit to the
product of the rms. values of current and voltage. The difference between the two is caused
by reactance in the circuit and represents power that does no useful work.
Protective Relay — A relay device designed to trip a circuit breaker when a fault is
detected.
Reactive Power — The portion of electricity that establishes and sustains the electric and
magnetic fields of AC equipment. Exists in an AC circuit when the current and voltage are
not in phase.Measured in VARS.
Rectifier — An electrical device that converts an alternating current into a direct one by
allowing a current to flow through it in one direction only.
Relay — An electrical coil switch that uses a small current to control a much larger current.
Reluctance — The resistance that a magnetic circuit offers to lines of force in a magnetic
field.
Resistance — The opposition to the passage of an electric current. Electrical resistance

can be compared to the friction experienced by water when flowing through a pipe.
Measured in ohms.
Resistor — A device usually made of wire or carbon which presents a resistance to current
flow.
Rotor — The rotating part of an electrical machine such as a generator, motor, or

alternator.

Self Induction — Voltage which occurs in a coil when there is a change of current.
Semiconductor — A solid substance that has a conductivity between that of an insulator

and that of most metals, either due to the addition of an impurity or because of temperature
effects. Devices made of semiconductors, notably silicon, are essential components of most
electronic circuits.
Series-Parallel Circuit — A circuit in which some of the circuit components are connected
in series and others are connected in parallel.
Series Circuit — A circuit in which there is only one path for electricity to flow. All of the
current in the circuit must flow through all of the loads.
Service — The conductors and equipment used to deliver energy from the electrical supply
system to the system being served.
Short Circuit — When one part of an electric circuit comes in contact with another part of
the same circuit, diverting the flow of current from its desired path.
Solid State Circuit — Electronic (integrated) circuits which utilize semiconductor devices
such as transistors, diodes and silicon controlled rectifiers.
Transistor — A semiconductor device with three connections, capable of amplification in

addition to rectification.
True Power — Measured in Watts. The power manifested in tangible form such as
electromagnetic radiation, acoustic waves, or mechanical phenomena. In a direct current
(DC) circuit, or in an alternating current (AC) circuit whose impedance is a pure resistance,
the voltage and current are in phase.
VARS — A unit of measure of reactive power.Vars may be considered as either the

imaginary part of apparent power, or the power flowing into a reactive load, where voltage
and current are specified in volts and amperes.
Variable Resistor — A resistor that can beadjusted to different ranges of value.
Volt-Ampere (VA) — A unit of measure of apparent power. It is the product of the rms
voltage and the rms current.
Volt (V) — A unit measure of voltage. One volt is equal to the difference of potential that
would drive one ampere of current against one ohm resistance.
Voltage — An electromotive force or "pressure" that causes electrons to flow and can be
compared to water pressure which causes water to flow in a pipe. Measured in volts.
Voltmeter — An instrument for measuring the force in volts of an electrical current. This is
the difference of potential (voltage) between different points in an electrical circuit.
Voltmeters have a high internal resistance are connected across (parallel to) the points

where voltage is to be measured.
Watt-hour (Wh) — A unit of electrical energy equivalent to a power consumption of one

watt for one hour.
Watt (W) — A unit of electrical power. One watt is equivalent to one joule per second,
corresponding to the power in an electric circuit in which the potential difference is one volt
and the current one ampere.
Wattmeter — The wattmeter is an instrument for measuring the electric power (or the
supply rate of electrical energy) in watts of any given circuit.
Waveform — A graphical representation of electrical cycles which shows the amount of

variation in amplitude over some period of time.
VI. Self-Evaluation:
Answer thefollowing question:
1. Give at least 10 unit of measurement used in electrical utilities and define each.
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VII. Review of Concept:
Alternating Current (AC) — An electric current that reverses its direction many times a
second at regular intervals.
Ampacity — The maximum amount of electric current a conductor or device can carry
before sustaining immediate or progressive deterioration.
Capacitance — The ability of a body to store an electrical charge. Measured in farads as

the ratio of the electric charge of the object (Q, measured in coulombs) to the voltage
across the object (V, measured in volts).
Circuit — A closed path in which electrons from a voltage or current source flow. Circuits
can be in series, parallel, or in any combination of the two.

Circuit Breaker — An automatic device for stopping the flow of current in an electric circuit.
To restore service, the circuit breaker must be reset (closed) after correcting the cause of
the overload or failure. Circuit breakers are used in conjunction with protective relays to
protect
Current (I) — The flow of an electric charge through a conductor. An electric current can be
compared to the flow of water in a pipe. Measured in amperes.
Cycle — The change in an alternating electrical sine wave from zero to a positive peak to
zero to a negative peak and back to zero. See Frequency.
Dielectric strength — The maximum electric field that a pure material can withstand under
ideal conditions without breaking down (i.e., without experiencing failure of its insulating
properties).
Direct Current (DC) — An electric current that flows in only one direction.
Electron theory — The theory which explains the nature of electricity and the exchange of
"free" electrons between atoms of a conductor. It is also used as one theory to explain
direction of current flow in a circuit.
Ground Fault Circuit Interrupters (GFCI) — A device intended for the protection of
personnel that functions to de-energize a circuit or portion thereof within an established
period of time when a current to ground exceeds some predetermined value that is less
than that required to operate the overcurrent protective device of the supply circuit.
Ohm's Law — The mathematical equation that explains the relationship between current,
voltage, and resistance (V=IR).
Open Circuit — An open or open circuit occurs when a circuit is broken, such as by a
broken wire or open switch, interrupting the flow of current through the circuit. It is
analogous to a closed valve in a water system.
Parallel Circuit — A circuit in which there are multiple paths for electricity to flow. Each
load connected in a separate path receives the full circuit voltage, and the total circuit
current is equal to the sum of the individual branch currents.
Semiconductor — A solid substance that has a conductivity between that of an insulator

and that of most metals, either due to the addition of an impurity or because of temperature
effects. Devices made of semiconductors, notably silicon, are essential components of most
electronic circuits.
Series-Parallel Circuit — A circuit in which some of the circuit components are connected
in series and others are connected in parallel.
Series Circuit — A circuit in which there is only one path for electricity to flow. All of the
current in the circuit must flow through all of the loads.
VIII. References

Book and e-book
• Grondzik, etal., 2019, Mechanical and Electrical Equipment for Buildings 13th
Edition, Wiley, USA
• Wujek, etal., 2010, Mechanical and Electrical Systems in Architecture, Engineering
and Construction. 5th edition, Pearson, USA
• Janis, etal., 2018, Mechanical & Electrical Systems in Buildings, 6th edition, Pearson,
USA
• Salavana, George, 1999, Architectural Utilities 2 Electrical and Mechanical
Equipment, JMC Printing press, Philippines

Module No. 2
ELECTRICAL THEORY
I. Topic:
• Unit of Electric Current
• Unit of Electric Potential
• Unit of Electric Resistance
• Circuit Arrangements
• Direct Current And Alternating Current (D-C) And (A-C)
• Electric Power Generation
II. Time Frame:4 hours
III. Introduction:
Working as an engineer requires many skills. The physical demands of the job are one
important part of the skills needed to succeed. Reading and communication skills are other
aspects one must develop and improve to be a successful worker in the electrical field.
Electrical theory is a basic building block that every potential electrician must understand
from the start. Electricity makes no sound, doesn’t have an odor, and can’t be seen, so
understanding the power you’re dealing with in theory, helps to make you and others safe.
Electrical theory is important to understand the function and operation of electrical
equipment to ensure proper installation and to complete tasks such as troubleshooting
electrical systems and equipment. Much has to be learned to fully understand electrical
theory, and it takes years to master. This activity plan will cover the basics, and it should be
understood that students will need to continue to develop their math and science
proficiencies if they intend to become an engineer.
IV. Objectives:
At the end of the lessons the student should be able to:
1. Elaborate the electrical theories;

2. Calculate energy and cost of operation of electrical equipment; and
3. Name, describe and distinguish between types of electrical circuits and compute
circuit loads.
V. Learning Activities
WHAT IS ELECTRICITY ENERGY
In terms of natural resources electricity is an expensive form of energy. Since the efficiency
of heat-to-electricity conversion, on a commercial scale, rarely exceeds 40%. Electricity
constitutes a form of energy itself which occurs naturally only in unusable forms such as
lightning and other static discharges or in the natural galvanic cells, which cause corrosion.
The primary problem in the utilization of electric energy is that, unlike fuels or even heat, it
cannot be stored and therefore must be generated and utilized at the same instant.

UNIT OF ELECTRIC CURRENT
THE ''AMPERE"
When electricity flows in a conductor, a certain number of electron pass a given point in the
conductor in 1 second. Numerically, an ampere of current flows in a conductor when 6.25 x
1018 electrons pass a given cross section in 1 second. Current or amperage is abbreviated
Amp, Amps or a. (on 120 volt service, the ordinary 100 Watt lamp filament carries about
0.833 amp, the motor for a desk calculator. about 1.00 amp.} Current is represented in
equations by 1.
It is convenient to establish an analogy between electric systems and mechanical systems

as an aid to comprehension. Current, or amperage, is a measure of flow and, and such,
would correspond to water flow in a hydraulic system. The correspondence is not complete,
however, since in the hydraulic system the velocity of water flow varies, whereas in the
electric system the velocity of propagation is constant and maybe considered
instantaneous; hence, the need to utilize the electric energy the instant it is produced.
UNIT OF ELECTRIC POTENTIAL

THE "VOLT" OR "V"
The electron movement and its concomitant energy, which constitutes electricity is caused
by creating a higher positive electric charge at one point on a conductor than exists at
another point on that same conductor. This difference in charge can be created in a number
of ways. The oldest and simplest method is by electrochemical action, as in the battery. In
the ordinary dry cell, or in a storage battery, chemical action causes positive charges {+}to
collect on the positive terminal and electrons or negative charges (-J to collect on the
negative terminals. There is a definite force attraction, or tendency to flow, between the
electrified particles concentrated at the positive and negative terminals. Potential difference
or Voltage is the name given to this electromotive force {emf}. This force is analogous to
pressure in a hydraulic or pneumatic system. Just as the pressure produced by a pump or
blower causes water or air to flow in a connecting pipe, so too the potential (emf, voltage)
produced by a battery (or generator) causes current to flow when the terminals between
which a voltage exists are connected by a conductor.

The higher the voltage (pressure}, the higher the current (flow) for a given resistance
(friction).
UNIT OF ELECTRIC RESISTANCE:

THE OHM
The flow of fluid in a hydraulic system is impeded by friction; the flow of current in an
electric circuit is impeded {resisted) by resistance, which is the electrical term for friction. In
a direct-current circuit (d-el this unit is called resistance and is abbreviated R; in an
alternating current circuit (a-c) it is called impedance and is abbreviated Z. The unit of
measurement is called the ohm.
Materials display different resistance to the flow of electric current. Metals generally have
the least resistance and are therefore called conductors. The best conductors are the
precious metals-silver, gold, and platinum-with copper and aluminum only slightly inferior.
Conversely, materials that resist the flow of current are called insulators. Glass, mica,
rubber, oil, distilled water, porcelain, and certain synthetics such as phenolic compounds
exhibit this insulating property and are therefore used to insulate electric conductors.
Common examples are .rubber and plastic wire coverings, porcelain lamp sockets, and oil-
immersed switches.
OHM'S LAW
The current I that will flow in a d-e circuit is directly proportional to the voltage V and
inversely proportional to the resistance R of the circuit. Expressed as an equation, we have
the basic form of Ohm's law that v I = -R that is, a current 1 is produced that is proportional
to the electric pressure V and inversely proportional to the electric friction R.
CIRCUIT ARRANGEMENTS

A) Series Circuits
The elements are connected one· after the other in series. Thus, the resistance and
voltages add.
An electric circuit may be defined as a complete conducting path that carries current from a
source of electricity to and through some electrical device (or load} and back to the source.
A current can never flow unless there is a complete (closed) circuit.
In any series circuit, the total Resistance R is the sum of the resistance around the circuit.
Thus,
The battery voltage may be called Vab = 120v The voltage across the load resistance, V cd
= 115v The resistance of the two wires rbc = rda = 0.04 ohm.
A practical application of series circuits is found in an incandescent lamp street lighting

circuits. The figure below explains that loss of one lamp can disable the entire circuit.
Furthermore, the point of fault is difficult to pinpoint, necessitating individual testing oflamps.
B.) Parallel Circuits
When two or more branches or loads in a circuit are connected between the same two
points, they are said to be connected in parallel or multiple. Such an arrangement and its
hydraulic equivalent are shown below.
From the circuit shown below, it should be apparent that multiple loads are across the same
voltage and, in effect, constitute separate circuits. From this we conclude that in the circuit
is the sum of the individual currents flowing in the branches that is,

Loads connected in parallel are equivalent to separate circuits superimposed into a single
connection. Each load acts as an independent circuit unrelated to, and unaffected by the
other circuits. Notice that the total current flowing in the circuit is the sum of all the
branches, but that the current in each branch is the result of a separate Ohm's Law
calculation. Thus in the 10-ohm load a 12·amp current flows and so forth.
V 120
I= I= = 12 amps Branch 1
R 10
120
I= = 1 amps Branch 2
120
120
I= = 10 amps Branch 3
12
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23 amps total current
The parallel connection is the standard arrangement in all building wiring. A typical lighting
and receptacle arrangement for a large room is shown below.

Here the lights constitute one parallel grouping, .and the convenience wall outlets constitute
a second parallel grouping. The fundamental principle to remember is that loads in parallel
are additive for current, and that each has the same voltage imposed.
Current is inversely proportional to resistance. Thus as resistance drops, current rises

under ordinary conditions that circuit will carry 10 amp.and will operate normally.But.if by
some mischance, a connection appears between points a and b, the circuit is shortened so
that there is no resistance in the circuit. The current rises instantly to a very high level, and
the condition constitutes a short circuit. If the circuit is properly protected, the fuse or circuit
breaker will open, and the circuit will be disabled, If not, excessive current will probably start

a fire.
DIRECT CURRENT AND ALTERNATING CURRENT (D-C) and (A-C)
Direct current- whenever the flow of electric current takes place at a constant time rate,
practically unvarying and in the same direction around the circuit. The terms universally
accepted are "d-e voltage" or "d-e current". The d-e voltages of 1.5v positive polarity, and
1.0v negative polarity is shown below,
a) GRAPHIC representation of d-e voltages with positive and negative polarity
b)CIRCUIT SYMBOL representation of BATTERY SOURCE
Alternating Current -whenever the flow of current is periodically varying in time and in
direction, as indicated by the symmetrical positive and negative loops or sine waves as in
the figure 2, it is called an alternating current.
Atoms of different elements differ from one another in the number of electrons and protons
− +
The distance along the time axis spanned by a positive and negative a-c loop is called one

cycle of time. Modern a-c systems in the United States operates at 60 ~cycles per second,
or 60 hertz. This means that current at 60 hertz'(Hz} is delivered to the consumer. In a-c,
instead of resistance, the corresponding parameter in an a-c circuit is impedance, which is
also measured in ohms. Thus for an a-c circuit, the equivalent to Ohm's Law is
V
I = ZWhere z is the symbol normally used for impedance
ELECTRIC POWER GENERATION
a) Direct Current-Since the d-e generator is in reality an a-c generator with a device
(commutator), attached, which rectifies the a-c to d-c, the battery is still the only major direct
source of direct current. The d-e generators are used where accurate speed control is
desired, for example, for elevators, or where d-e is required on a larger and more sustained
basis than would be economical for batteries. Of course, a rotating d-e generator unlike a
battery, must be driven to produce power. The prime mover can be a motor, engine,
turbine, or any other device that will provide the required input power.
Another source of d-e power is rectification of a-c that can be accomplished on any desired
scale to provide as much d-e power as there is available a-c power. Various types of
rectifiers are in commercial use, including selenium, silicon and copper-oxide types.
b) Alternating Current-Alternating current is produced commercially by an a-c generator,

called an alternator. The prime mover, as in the case of the d-e units may be any type of
engine or Turbine. The process by which electricity is produced is shown in • the figures
below. This principle of electromagnetic induction states that when an electrical conductor
is moved in a magnetic field, a voltage is induced in it. The directions of the movement
determine the polarity of the induced voltage as shown.

Voltage is picked off with sliding contacts, called "slip-rings".
It does not matter whether the conductor moves and the magnetic field is stationary, or vice
versa, as long as there is relative motion between the two.
VI. Self-Evaluation
Answer the following questions:
1. What are the types of circuit arrangement? Describe each?

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2. Differentiate direct current from electric current.
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VII. Review of Concept:
• Electricity is an expensive form of energy. Since the efficiency of heat-to-electricity

conversion, on a commercial scale, rarely exceeds 40%.
• Ampere (A) is a unit of measure for the intensity of an electric current flowing in a

circuit. One ampere is equal to a current flow of one coulomb per second.
• The higher the voltage (pressure}, the higher the current (flow) for a given resistance
(friction).
• The flow of fluid in a hydraulic system is impeded by friction; the flow of current in an
electric circuit is impeded {resisted) by resistance, which is the electrical term for
friction.
• OHM’s Law “The current I that will flow in a d-e circuit is directly proportional to the
voltage V and inversely proportional to the resistance R of the circuit.”
VIII. References
Books and e-book
Edition, Wiley, USA
USA

Module no. 3
ELECTRICAL MATERIALS
I. Topic:
• Building Electrical Service Equipment
• Power and Energy
• Power in Electric Circuits
• Energy in Electric circuits
• Electric Load Control
II. Time Frame: 3 hours
III. Introduction:
Electrical materials are important in engineering utilities. All of electrical engineering is

founded on the interaction of electricity and magnetism within material systems. Materials
and components permit the realization of concepts imagined by humankind. They also
determine the limits of this realization.
IV. OBJECTIVES:
At the end of the lesson, the students should be able to:
1. Name the electrical material used in electricity; and

2. Solve energy from power and time.
3. Discuss the different types of electric load control.
V. LEARNING ACTIVITIES:
BUILDING ELECTRICAL SERVICE EQUIPMENT
Service Entrance Conductors

Underground or overhead service entrance conductors carry power from the transformer
through a metering device to the building’s service disconnects. Overhead wires extend
from a pole-mounted distribution transformer to the building’s service entrance and are
generically referred to as the service drop.
Service Entrance
The service entrance includes the components that connect the utility-supplied wiring (the
service lateral or service drop) to the service disconnect, excluding the utility’s conductors.
The electric meter is an instrument that is used by the utility company to measure and
record electrical energy consumed.
A service disconnect is a required part of the service entrance equipment that allows
electrical service from the utility company to be switched off so that power is disconnected
to the building installation.

Switchboards
A switchboard is a large cabinet or assembly of metal cabinets in which is connected
disconnecting switches, overcorrect protection devices (fuses or circuit breakers), other
protective devices, FIGURE 18.2 A typical service entrance/panelboard configuration in a
simple residential building electrical system consists of several circuits extending from the
panelboard to outlets throughout a building, much like branches extend from a tree’s trunk.
The main disconnect (contained behind the door of the panelboard) is not shown and
instruments designed to divide large amounts of electrical current into smaller amounts of
current used by electrical equipment. It contains one or more devices that can be used to
manually and automatically disconnect a circuit from its power source.
Panelboards
A panelboard is one or more metal cabinets that serve as a single unit, including buses,
automatic overcurrent protection devices (fuses or circuit breakers). It is equipped with or
without switches for the control of light, heat, and power circuits. By definition, a panelboard
is a cabinet or cutout enclosure placed in or against a wall or partition that is accessible
from the front.
Building Transformers
Transformers are used in transmitting and distributing power from the power plant to a
substation. The operation of a large commercial installation depends on power distribution
and phase of electrical power nearby and within a building. Building transformers are rated
in kVA. Typical sizes used in buildings include 3, 6, 9, 15, 25, 30, 37.5, 45, 50, 75, 112.5,
150, 225, 300, 500, 750, 1000, 1500 kVA, and larger. Every transformer comes with a
nameplate that typically identifies:
• Rated kVA

• Primary and secondary voltage

• Impedance (if 25 kVA or larger)
• Required clearances (if it has ventilating openings)
Circuit Breakers
A circuit breaker is an overcurrent protection device that serves two purposes: It acts as a
switch that can be opened and closed manually, and most importantly, it automatically “trips
off,” which opens the circuit when current flowing through it exceeds the circuit rating. This
action instantaneously interrupts current flow. Once it trips, it can be reset (closed like a
switch) and will continue to allow electricity flow as long as the current flowing through it
does not exceed the circuit rating. Various types of circuit breakers are shown in Photo
18.7.
Fuses
A fuse is an overcurrent protection device that consists of a strip of metal with a low melting
temperature. Under normal operation, electricity flows through the metal strip.
Outlets, Receptacles, and Plugs

In an electrical system, an outlet is the location in a branch circuit where electricity is used.
For example, a lighting outlet is the location in a branch circuit where conductors provide
power to a light fixture. A receptacle is a female connecting device with slotted contacts. It
is installed at an outlet or on equipment, where it is intended to easily establish an electrical
connection with an inserted plug. A plug is a male connecting device that has two or more
prongs that are inserted into a receptacle to connect to an electrical circuit. A plug is
typically connected to a flexible cord that is attached to a portable appliance, light, or
equipment. Receptacles and plugs offer a simple way to attach or detach an appliance or
piece of equipment to/from an electrical outlet.
Switches
A simple switch is a device placed between two or more electrical conductors in a circuit to
safely and intentionally open or close the circuit or to redirect the path of current in a circuit.
Contacts in a switch open (switches off) a circuit, close (switches on) a circuit, or divert
current from one conductor path to another. Switches are rated by purpose, voltage, and
amperage, and are classified for AC or DC.
Safety switches are used in building electrical systems. They are designed to reduce the
possibility of contact with bare electrical conductors and have current interrupting capability.
CONDUCTORS

Wire
An electrical conductor is any material that conducts electrical current. A wire is a common
electrical conductor. Most conductors used in building applications are classified according
to a wire gauge standard and on the cross-sectional area of the wire in units called circular
mils. A mil is equal to 1>1000 inch, so one circular mil (cmil) is equal to the cross-sectional
area of a 0.001 in diameter circle.
Buses
A bus, sometimes called a bus bar, is an electrical conductor (usually copper or aluminum)
that serves as a common connection for two or more electrical circuits. Buses are typically
solid bars used for power distribution. They are commonly found in panelboards,
switchboards, and other power distribution equipment
Conductor Insulation
Conductors are covered with insulation that provides electrical isolation and some physical
protection of the conductor material. It prevents loss of power and the danger of short
circuits and ground faults. The type of insulation protecting a conductor determines the
environment in which it can be used safely.
Cable
A cable contains more than one conductor bundled together in a factory assembly of wires.
An outer sheathing encases and protects the conductors, simplifying installation of multiple
wiring.
Cords
Cords are made of stranded conductors within a flexible insulated sheathing material. They
are designed for flexibility andbending. Cords are generally manufactured of a lighter gauge
(e.g., No. AWG 18 or No. AWG 16) stranded conductors. They are designed for use on
power tools, large stationary equipment, or detachable computer power cords. Extension
cords are made of stranded wires because they require flexibility, allowing the cord to be
bent and twisted without stressing the conductors. Concealed Knob-and-Tube
Wiring
Concealed knob-and-tube (K&T) wiring consists of an old style wiring technique using
insulated conductors strung between glass or porcelain knobs and tubes. In this wiring
method, the ungrounded (hot) wire is run along one side of the joist/stud bay and the
neutral is run along the other. To secure it to the wood, the wire is wrapped around ceramic
knobs spaced every 18 in or so. To penetrate a joist/stud and prevent abrasion, the wire is
separated from the wood joist/stud by a ceramic tube.
POWER AND ENERGY

Energy-is the technical term for the more common expression-work. In terms of power, it is
the product of power and time, that is
Energy or work = power x time
In practical terms, energy is synonymous with fuel and therefore also cost. Thus energy can
be expressed as barrels (tons) of oil, cubic feet (cu. Meters) of gas, tons of coal, kilowatt
hours of electricity usage, and dollars/pesos of operating cost. The concept of energy

efficiency of structures can be stated in terms of annual usage of oil, gas, and electricity or
alternatively in terms of$, 'P'or of total fuel cost. In technical terms. Energy is expressed in
units of Btu {calories), foot-pounds (joules), and kilowatt-hours.
Power is the rate at which energy is used, or alternatively, the rate at which work is done.
Since energy and work are synonymous.
The term power implies continuity, that is, the use of energy at a particular rate, over a given,
generally considerable, span of time. Thus multiplying power by time yields energy. Typical
units of power in the English-system are horsepower, Btu per hour, wall and kilowatt. In the
metric or Sl System the corresponding units are joules per second, calories per second, watts
and kilowatts. In physical terms power is also the rate at which fuel (energy) is used. Thus
power can also be expressed as gallons (liters) of oil per hour, cubic feet (cu. meters) of gas
per minute, and tons of coal per day.
POWER IN ELECTRIC CIRCUITS
The unit of electric power is the watt (W}. A larger unit of 1000 watts is the kilowatt (kw). The
power input in watts to any electrical device having a resistance R and in which the current is
I is given by the equation:
Wattage W =I2R or W = I (IR)
This is true for both a-c and d-e circuits. However, since the resistance of an item is generally
not known, but tile circuit voltage and current are known. It would be preferable to calculate
Power in this equation.
By Ohm's Law V = IR R in Ohms

and since W = I (IR) W in Watts
W = I (V) I in amperes
V in Volts
Example: Incandescent lamp = 66 ohms Resistance

115V Supply
𝑉 115
I = = = 1.74
𝑅 66
d-c W = VI= 115 (1.74) = 200watts
power drawn
in a-c multiply x pf.

Example:
Calculatethe current and power in two branches of the circuit and the total circuit current assume a
120 v a-csource.
a)Power= VI
P= 150 + 150 + = 300 w 300 W = 120 x I

300
I= = 2.5 amperes
120
𝑉 120
R= = 48 ohms
𝐼 2.5
b) Second branch is 10 amp. 0.8 pf load
Power = V x amp x pf
= 120 X 10 X 0.8 = 960 W
but the circuit volt - ampere

is. 120 x 10 = 1,200 Va.
ENERGY IN ELECTRIC CIRCUITS
Since power is the rate of energy use, it follows that energy = power x time. Therefore theamount of
energy used is directly proportional to the power of the system and to the lengthof time. It is in
operation. Since power is expressed in either watts or kilowatts, and time inhours (second and
minutes are too small for use), we have for units of energy: watt-hours (wh) or kilowatt-hours (kwh)
energy used for one hour.
Example:
a) Find the daily energy consumption of the appliances listed below if they are used daily for the
amount of time shown.
Toaster (1340 w) or 1.34 kw 15 min. or % hr.

Percolator (500 w) or 0.5 kw 2 hr.
Fryer (1560 w) or 1.56 kw 39 min. or Y.! hr.
Toaster = 1.34 kw x % hr. = 0.335 kwh

percolator = 0.5 kw x ~hr. = 1.00 kwh
fryer = 1.56 kw. x Y.! hr. = 0.78kwh
iron = 1.40 kw x % hr. = 0.70 kwh
Total = 2.815·kwh
b) If the average cost of energy is per kilowatt-hour, find the daily operating cost
2.815 kwh x /kwh= Ᵽ________.
c) If considering an average power demand of a household is 1.2 kw. Calculate the monthly electric

bill of such a household, assuming the rate of per kilowatt hour = Ᵽ________.
Monthly energy consumption
. 24 hr. 30 days
= 1.2 kw x x = 864 kwh.
day month
Electric power bill.

= 864 kwhX Ᵽ________/kwh = Ᵽ_________.
ELECTRIC LOAD CONTROL
A method of load control for efficient utilization of available energy to produce a high load factor.
This results in a lowering of demand charge, (levying of a charge for power (kw) in addition to the
normal energy (kwh} charge. This demand charge is primarily useful in encouraging users to reduce
to their peak loads. In so doing, energy use is also reduced somewhat}. and secondarily in a
reduction of energy costs. (An ancillary, but important, benefit is the maximum utilization of electrical
power equipment, which normally runs underloaded. This results in smaller equipment, lower first
cost, and less space utilization). The control devices and systems are variously referred to as load
shedding control, peak demand control, peak load regulation, power use control, and permissive
load control.
a) Levei1-Load scheduling and duty-cycle control
The simplest and most applicable to all types of facilities. The installation's electric load are
analyzed and then scheduled to restrict demand. Thus large loads can be shifted to off-peak hours
and controlled to avoid coincident operation. The user can also take advantage of special-night and
weekend-utility rates for loads that do not require immediate operation, such as battery charging
and transfer pumping. Control can be entirely manual or automated by use of a duty-cycle
controller. This device is essentially a program clock with switching for a number of circuits or loads.
Typical applications of this device are control of HVAC (heating, ventilation, aircon) loads, lighting
load and process loads. Although such as analysis is a necessary first step in all levels of electric
load control its efficacy is limited since many of the loads are automatically controlled. Thus
compressors controlled by pressure switches, fans controlled by thermostats, ·and pumps controlled
by float switches cannot be scheduled with this type of duty-cycle controller and coincident
operation cannot be prevented.

THE HEART OF A DUTY-CYCLE CONTROLLER

Is the program drum andassociated controlled contacts. The terminalstrips are wired to the
drum contactsand then to the controlled loads.
USEFULNESS OF DUTY - CYCLE
1. Eliminating energy waste by shutting down units when not required.

2. Automatic control such as preheat and precool, which results in lower power and energy levels.
3. Establishment of efficient equipment scheduling without continual manual supervision
c) Level 3-Automatic Instantaneous Demand Control
This type of control {also called "rate control") is, in effect, an automated version of the level-2
system. The unit accepts instantaneous kw load information from the utility system either in the form
of continuous current readings or in the more sophisticated form of pulsed energy data. It then
compares this information to the preset Kw limit (rate control) and acts automatically to disconnect
and reconnect loads as required. These units do not recognize the utility's metering interval of 15 or
30 min., but act continuously on the basis of load comparison data. The first step in setting up this
system is to separate the controllable ("sheddable") loads from those that must remain
uninterrupted. Depending on the type of facility the two lists that follow are typical.
"SHE DOABLE"
Non-essential lighting Sewage Ejectors with

Ventilation fansappropriate level controls
Space heating Transfer pumps
Comfort Cooling Any device with
Non-critical batch flywheel effect
Process equipment (Electric snow melting)
Electric Boilers
NONSHEODABLE"
Essential lighting Process equipment

Elevators Material bandling
Refrigeration Equipment
Compressors Office machinery

The nonsheddable loads are fed directly from the power line. The sheddable loads are fed via a
panel of control relays that respond to on/off instructions from the demand controller. The facility's
operator will then analyze the sheddable loads and determine a minimum coincident kw load for this
group. This figure when added to total coincident ofthe nonsheddableloads, becomes the kw rate
control or the set point.
BLOCK DIAGRAM of a system of Automatic electric power control. The demand controller receives
instantaneous load data from the metering equipment, compares it to present limits, and
disconnects and reconnects controllable loads automatically to keep load within these limits.
To avoid excessive cycling of loads a variable width Kw band around the set point is used. Note that
the controller acts to reduce maximum loads (peaks) and in low points(valleys) 15% of energy is
saved.
This demand control unit operates on

the rate control principle, keeping the
demand within a band around the set
point.
d) Level 4-ldeal Curve Control

This demand control unit operates on the rate control principle, keeping the demand within a band
around the set point.
This controller operate by comparing the actual rate of energy usage to the ideal rate and controls
kw demand by controlling the total energy used within a metering interval.
GRAPH of a cumulative energy use over a demand Interval. (Energy use is the time integral of
power; i.e., kwh=kw x time)
The desirable of energy use is the“ Ideal Curve” as

shown in this figure.
Graph (b) showing an offset, which establishesan"

ideal curve" to which actual energy use
willbe compared by the controller. In
decidingwhether to shed or add loads.

e)Level 5-Forecasting Systems
These systems are the most sophisticated, the most expensive, and the most effective. They are
best applied to large structures where the number of loads, load patterns, and complexity of
operation precludes the partially manual operation of the preceding systems. As a result of the large
amount of load data, these systems frequently are installed as part of the computerized Central
control facilities in. large Industrial plants, skyscrapers, and very large institutional facilities. The
units operate by continuously forecasting the amount of energy remaining in the demand interval,
based on kwhpulse data received. They then examine the status and priority of each of the
connected loads and decide on a course of action.
ELECTRICAL MEASUREMENTS
To measure energy, the factor of time must be introduced, since ... energy = power x time. a-c watt-
hour meters are basically small motors, whose speed is proportional to the power being used. The
number of rotations is counted on the dials which are calibrated directly in kilowatt-hours.
Schematic Arrangement of Wattmeter connections. Note that the current coil is in series with the
circuit load, whereas the voltage loads are in parallel.

TYPICAL INDUCTION-TYPE Kwh. Meter with Kw demand dial. Decade dials register total disc revolutions that are
proportional to energy. Disc speed is proportional to power.
VI. SELF EVALUATION
Answer the question:
1. What are the types of electric load control? Define each.

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VII. REVIEW OF CONCEPT
• Energy-is the technical term for the more common expression-work.

• The unit of electric power is the watt (W}.
• Therefore the amount of energy used is directly proportional to the power of the
system and to the length of time
• Electric load control is a method of load control for efficient utilization of available
energy to produce a high load factor
IX. REFERENCES:
Books and e-books
Edition, Wiley, USA
USA

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LEARNING MODULE SURIGAO STATE COLLEGE OF TECHNOLOGY

I. Topic: Course Introduction

II. Time Frame:2 hours

At the end of the lessons the student should be able to:

1. Name and define common electrical terminology;

COMMON ELECTRICAL TERMINOLOGY

Ammeter — An instrument for measuring the flow of electrical current in amperes.

Ampere-Hour (Ah) — A unit of measure for battery capacity. It is obtained by multiplying

ES-141 ENGINEERING UTILITIES 1 (ARCH. MARLON C. SOLLOSO - ASSISTANT PROFESSOR III)

Armature — The movable part of a generator or motor. It is made up of conductors which

Capacitance — The ability of a body to store an electrical charge. Measured in farads as

Corona — A corona discharge is an electrical discharge brought on by the ionization of a

Dielectric constant — A quantity measuring the ability of a substance to store electrical

ES-141 ENGINEERING UTILITIES 1 (ARCH. MARLON C. SOLLOSO - ASSISTANT PROFESSOR III)

Ferroresonance — (nonlinear resonance) a type of resonance in electric circuits which

Generator — A device which converts mechanical energy into electrical energy.

ES-141 ENGINEERING UTILITIES 1 (ARCH. MARLON C. SOLLOSO - ASSISTANT PROFESSOR III)

the circuit is one henry.

Inductance — The property of a conductor by which a change in current flowing through it

Inverter — An apparatus that converts direct current into alternating current.

Kilowatt-hour Meter — A device used to measure electrical energy use.

Kilowatt (kW) — Equal to 1000 watts.

ES-141 ENGINEERING UTILITIES 1 (ARCH. MARLON C. SOLLOSO - ASSISTANT PROFESSOR III)

Ohmmeter — An instrument for measuring the resistance in ohms of an electrical circuit.

Piezoelectricity — Electric polarization in a substance (especially certain crystals) resulting

Resistance — The opposition to the passage of an electric current. Electrical resistance

Rotor — The rotating part of an electrical machine such as a generator, motor, or

ES-141 ENGINEERING UTILITIES 1 (ARCH. MARLON C. SOLLOSO - ASSISTANT PROFESSOR III)

Semiconductor — A solid substance that has a conductivity between that of an insulator

Transistor — A semiconductor device with three connections, capable of amplification in

VARS — A unit of measure of reactive power.Vars may be considered as either the

Variable Resistor — A resistor that can beadjusted to different ranges of value.

ES-141 ENGINEERING UTILITIES 1 (ARCH. MARLON C. SOLLOSO - ASSISTANT PROFESSOR III)

where voltage is to be measured.

Watt-hour (Wh) — A unit of electrical energy equivalent to a power consumption of one

Waveform — A graphical representation of electrical cycles which shows the amount of

Answer thefollowing question:

VII. Review of Concept:

Capacitance — The ability of a body to store an electrical charge. Measured in farads as

ES-141 ENGINEERING UTILITIES 1 (ARCH. MARLON C. SOLLOSO - ASSISTANT PROFESSOR III)

Semiconductor — A solid substance that has a conductivity between that of an insulator

ES-141 ENGINEERING UTILITIES 1 (ARCH. MARLON C. SOLLOSO - ASSISTANT PROFESSOR III)

Book and e-book

ES-141 ENGINEERING UTILITIES 1 (ARCH. MARLON C. SOLLOSO - ASSISTANT PROFESSOR III)

II. Time Frame:4 hours

At the end of the lessons the student should be able to:

1. Elaborate the electrical theories;

WHAT IS ELECTRICITY ENERGY

ES-141 ENGINEERING UTILITIES 1 (ARCH. MARLON C. SOLLOSO - ASSISTANT PROFESSOR III)

UNIT OF ELECTRIC CURRENT

It is convenient to establish an analogy between electric systems and mechanical systems

UNIT OF ELECTRIC POTENTIAL

ES-141 ENGINEERING UTILITIES 1 (ARCH. MARLON C. SOLLOSO - ASSISTANT PROFESSOR III)

UNIT OF ELECTRIC RESISTANCE:

ES-141 ENGINEERING UTILITIES 1 (ARCH. MARLON C. SOLLOSO - ASSISTANT PROFESSOR III)

A practical application of series circuits is found in an incandescent lamp street lighting

ES-141 ENGINEERING UTILITIES 1 (ARCH. MARLON C. SOLLOSO - ASSISTANT PROFESSOR III)

B.) Parallel Circuits

ES-141 ENGINEERING UTILITIES 1 (ARCH. MARLON C. SOLLOSO - ASSISTANT PROFESSOR III)