Transcript Adventures in Electrical Engineering

Or
Or
Adventures
in
Adventures
in
How
I
Spent
How
I
Spent
Electrical
Electrical
My Summer
Summer
My
Engineering
Engineering
Vacation
Vacation
Thomas Reed
Poteet High School
E3 Summer Research Program
At Texas A&M
Determining Potential Power
Transmission Line Failure
Dr. Butler-Purry’s Research
For insight on this project and its goals, read the notes in PowerPoint edit mode.
Short-Term Monitoring Experiments
Complete Setup Diagram
Fe e de r
(7200 V)
Cable Late ral
Subs tation
M e as ure m e nt
Units
Fe e de rs
Dis tribution
Trans form e r
7200:120/240 V
Phas e Curre nt
Ne utral Curre nt
Phas e Voltage
Analog Signal
Conditioning Unit
Output
Signals
Loads
Digital Com pute r
(Data Acquis ition
Sys te m )
Signal Measurement Units

Two clamp-on current transducers (Pearson Electronics, Inc.). Ratio =
Connected to the primary side of the transformer.

Voltage measurement from secondary side.
0.1 V/A.
Pad Mounted Transformer
Secondary
Side
Primary
Side
Phase
Current
Neutral
Current
Online, non-destructive
Project on Electricity
“What is Going On?”
Explanation of Project
Through a series of experiments with circuits,
building different types circuits using
batteries and resistors, and collecting and
analyzing data, students will discover
relationships between voltage, current and
resistance. Also, they will look at what
effect power has on the system and do
analysis on current and power usage.
Phase 1 of Project
• Students, in groups of two, are to “build”
the required circuits, using up to four size
D batteries (1.5v) and different size
resistors.
• They will examine simple circuits and
circuits in series and in parallel, and
determine relationships and write
equations.
Phase 2 of Project
• Students will be introduced to Power and
its relationship to voltage, current and
resistance.
• Students will then look at the power usage
in their own homes and determine power
and current usages for several scenarios
and design a room around current and
power usage.
Phase 1
Circuit Builders Project
What is Happening?
Experiment procedure:
Start with one battery in holder.
Attach clips to the ends of the resistor attach clips to battery pack.
Take volts reading. Record data.
Take amp reading. Record data.
Detach clips from battery pack.
Insert another battery into battery pack.
Repeat procedure until done with all four batteries.
When doing resistors in series or parallel attach resistors in proper sequence before attaching to
battery.
Repeat procedure as before.
Procedures document. Along with this page, students are
given directions on how to set up circuits.
All the worksheet can be accessed by double clicking the Word Document Icon in PowerPoints edit mode.
This is the initial
experiment to get the
project running. Helping
either whole class or
with the groups,
students are carefully
monitored to insure
desired outcomes.
This experiment is to have data
to compare with the first so the
students will have more than
one example to draw from when
they are writing the general
equation.
Experiment 2. Page 2
From the two experiments, can you generalize the relationship using the variables for
voltage (V), current (I), and resistance (R)?
Experiment 2 (using equation developed)
b) Predict the current in amps (I) using the four voltages and a 10  resistor.
In this portion of the project
they are to derive the general
equation V=IR, or variant,
from previous experiments
and are to verify their
findings in another
experiment.
V
I
1.5
3
4.5
6
Run experiment using a 10 W resistor to confirm predictions.
V
I
Does the data collected agree with the predicted data? (Here you should put the voltage
found into the equation developed.)
Does the general equation hold up for this situation?
Here students will begin to
understand what happens when
resistors are put into series.
Now students will verify
previous findings and write
a generalized equation for a
general series.
Students explore resistors
in parallel. In groups,
students collect data. As
whole class, discuss
outcomes and relate to
previous experiments and
aide students in finding
correct relationship.
Here students explore
parallel resistors again.
They collect data and
determine formula for the
resistance of the circuit
with aide of teacher in
whole class discussion.
Phase 2
Home Project
Phase 2
POWER
P=VI and P=I2R are the equations for power (wattage used)
In this Phase of the project,
students take a look at
If you are given the wattage of a device, knowing the voltage, you can determine the
resistance and the current used. Using substitution and the numbers from fist
experiment, determine the wattage (W) used by the circuit.
POWER. They are given
How can you determine the current (amps) used in an electrical device if you are only given
its wattage (remember that most household outlets have 120v)?
How much current (amps) does a sound system rated at 100 watts use?
How much resistance (ohms) does a sound system rated at 100 watts use?
How much power (watts) does a device with a current of .5A use?
A typical light bulb draws 75 watts, how much current (amps) does it draw? What is its
resistance?
the power equation, P= VI &
P=I2R, and are to find for
missing value in several
situations.
Phase 2 Project
Part 1
In your home, select a room. Find the wattage of all electrical devices being used in
that room.
List items and their wattages, and give total wattage.
In this section of the
project, the students are
to look at the power
usage in their homes.
Determine the current (amps) required to run those devices, individually and
collectively.
List items and their current (amps) demands, give total amps required for room.
Phase 2
Phase 2
Part 2
Part 2, page 2
In your home, what room is most likely to throw a circuit breaker?
Find the combination of the MOST number of items that can be on before the circuit
breaker is tripped. List the items and their wattage and current demands.
Determine the power usage for each electrical device in the room and the current
required for each.
List items and their wattage and current demands.
Find the power usage for the whole room if everything was plugged in and on.
Find the current demand for the room.
What size circuit breaker does the room use?
Find the combination of the LEAST number of items that can be on before the circuit
breaker is tripped. List the items and their wattage and current demands.
In this part, students are to find out power
demands and current requirements for the room
the trips its circuit breaker most often. They are to
determine the maximum and minimum number
of items that can be plugged in and turned on
without tripping the breaker.
Phase 2
Part 3
In this portion of the project, you are to design a power/current
model for a room. You are to design the room around required
electrical items, plus any other items you wish to add to the room.
You decide what size and how many circuit breakers are needed for
the room. You must first find out the power usage for each electrical
item and its current draw (amps needed). Then you decide what size
circuit breaker and how many you would need to cover the room. In
this room you must have these items, you may have more, but the
following are required; a computer work station, including
monitor, cpu, and a printer, an entertainment center, including a
TV, a VCR and/or DVD player, a game station of some kind, and a
sound system of some kind, two light sources, and a clock or
clock radio. You are to list each item, giving the brand name, its
wattage and calculate its current need. On deciding what size breaker
to use, realize the larger the breaker, the higher the chance for over
heating the power lines in the walls. The largest size breaker should
be a 20A breaker; you may use 10A and/or 30A breakers as well.
This is the final stage
of the unit. The
students design the
electrical usage of a
room and decide on
number and type of
breakers needed.