2. Units to analyze
Unidad 1
Analysis of
electrical circuits
in AC.
•Phasors
•RCL Circuits
•mesh analysis
•power factor
•Design and simulation of AC circuits
Unit 2
Electric Power
Supply.
•AC generation principles
•Power supply, metering and monitoring features
•Transformer Principles of Operation and Equivalent Circuit
•Alternate sources of generation.
Unit 3
Residential,
Commercial and
Industrial Electrical
Installations
• Performance of electrical plans.
• Installation design and its validation.
• Facility computer-aided design and simulation software.
• Energy saving.
4. Industrial electricity?
• Branch of physics and engineering specialization that applies
mathematical knowledge in the study of systems whose
operation is based on the conduction and control of the flow of
electricity.
6. Basic concepts of electrical variables
• Electric charge
The charge of an electron and that of a
proton are equal in magnitude. Electric
charge, an electrical property of matter
that exists by virtue of excess or
deficiency of electrons, is symbolized
by "Q"
7. Materials with charges of opposite polarity attract
each other, and materials with charges of the same
polarity repel each other, as shown in the figure.
A force acts between the charges, evidenced by attraction
or repulsion. This force, called the electric field, is made up
of invisible lines of force, as shown in the figure below.
8. * Voltage
There is an attractive force between a positive and a negative charge. A certain
amount of energy, in the form of work, must be applied to overcome this force and
separate the charges by a certain distance.
All opposite charges have some potential energy due to the separation between
them. The potential energy difference per charge is the potential difference or
voltage. In electrical circuits, voltage is the driving force and is what establishes the
current.
9. Exercise
• If 50 J of energy is available for every 10 C of charge, what is
the voltage?
10. * Current
• Voltage provides energy to electrons, allowing them to move
through a circuit. This movement of electrons is current, which
produces work in an electrical circuit.
11. The attractive force produced by the positive voltage on the far right pulls the
free electrons to the right. The result is a net movement of free electrons from
the negative end of the material to the positive end.
12. The movement of these free electrons from the negative end of the material to
the positive end is the electric current, symbolized by I.
“Electric current is the speed of the flow of charge”
In a conducting material, the number of electrons (number of charge) that pass
a certain point in a unit of time determines the current.
13. • One ampere (1 A) is the amount of current that exists when a
certain number of electrons, whose total charge is one coulomb
(1 C), pass through a given cross-sectional area in one second
(1 s).
14. Exercise
Ten coulombs of charge flow past a certain point on a wire in 2 s.
What is the current in amperes?
15. * Resistance
When there is current in a material, free electrons move in it and
occasionally collide with atoms. These collisions cause the
electrons to lose some of their energy, thereby restricting their
movement.
The more collisions there are, the more the flow of electrons is
restricted. This restriction varies and is determined by the type of
material. The property of a material to restrict or oppose the flow of
electrons is called resistance, R.
16. Resistance is the opposition to the current. Resistance is
expressed in ohms, symbolized by the Greek letter omega (
).
There is one ohm (1) of resistance if there is one ampere (1 A) of
current in a material when a volt (1 V) is applied to the material.
The schematic symbol of resistance is shown in the figure
.
17. * Ohm's law
Ohm's Law mathematically describes the relationship between voltage,
current, and resistance in a circuit.
Ohm's law is expressed in three equivalent ways depending on what
quantity is required to be determined. As you will see, current and
voltage are linearly proportional. However, current and resistance are
inversely proportional
18. Ohm determined experimentally that if the voltage across a resistor
increases, the current through the resistor will increase; and likewise, if
the voltage decreases, the current will do the same.
“If the voltage doubles, the current will double. If the voltage is cut in half, the current
will too. "
19. • Ohm also determined that if the voltage is held constant, less
resistance produces more current, and more resistance produces less
current.
“If the resistance is cut in half, the current doubles. If the resistance doubles, the current is cut in
half ”.
20. • Ohm's law states that current is directly proportional to voltage
and inversely proportional to resistance:
• With a constant value of R, if the value of V increases, the value
of I increases; if V decreases, I decreases. If V stays constant
and R increases, I decreases. Likewise, if V remains constant
and R decreases, I increases
21. • In resistive circuits, current and voltage are linearly proportional.
Linear means that if one of the quantities increases or decreases by
a certain percentage, the other will increase or decrease by the same
percentage, assuming that the resistance value is constant.
The linear relationship of current and voltage
22. Exercise
Show or demonstrate that if the voltage present in the circuit of the
following figure is increased to three times its present value, the
current will triple its value
23. Example
Suppose you are measuring current in a circuit that operates with 25 V. The
ammeter reads 50 mA. Later, it is observed that the current has dropped to
40 mA. Assuming that the resistance did not change, it must be concluded
that the voltage source has changed. How much has the voltage changed
and what is its new value?
24. Example
Suppose five resistors are placed on
a prototype board as shown in Pic.
Connect them in series so that,
starting from the positive terminal (),
R1 is first, R2 is second, R3 is third,
and so on. Draw a diagram showing
this connection.
25. Suponga que se colocan cinco resistencias en una placa prototipo como se muestra en
la figura 5-3. Conéctelos en serie de modo que, comenzando por el terminal positivo (),
R1 sea el primero, R2 el segundo, R3 el tercero, y así sucesivamente. Dibuja un
diagrama que muestre esta conexión.
26. Red eléctrica
Una red interconectada que tiene el propósito
de suministrar electricidad de los proveedores
a los consumidores. Consta de tres
componentes principales, plantas generadoras
que producen electricidad a partir de
combustibles fósiles (carbón, gas natural,
biomasa) o no fósiles (eólico, solar, nuclear,
hidráulico); Líneas de transmisión que llevan la
electricidad desde las plantas generadoras
hasta los centros de demanda y
transformadores que reducen el voltaje para
que las líneas de distribución puedan entregar
la energía al consumidor final.
