ENGR 43
Lab Activity
Student Guide
LAB 1 – What’s a Watt?
Student Name: ___________________________________________________
Overview
Getting Started
In this lab activity, you will make several
different measurements with the Kill-A-Watt
power monitor on common electrical and
electronic devices. You will compare your
measurements to rated values on the
devices, evaluate the data, draw conclusions
where possible, and save the data for use in
a later activity.
Lab Activity and Deliverables:
It should take students approximately 2
hours to complete the lab activity, and 1
hour of homework time to complete the lab
report.
Equipment & Supplies
Item
All equipment stations set up
by instructor
Before Starting This Activity
All online documents for the labs are on
GoggleDocs. A link to the master list of
documents is:
http://tinyurl.com/engr43-lablinks
This file has links to all of the other
documents needed for the lab activities.
When downloading documents, be sure to
right-click on the link and save the file to
your disk or flash drive before entering data.
Quantity
1
Special Safety Requirements


Learning Outcomes For Activity
Relevant knowledge (K), skill (S), or
attitude (A) student learning outcomes
Use common safety precautions when
working near fans and hot lights.
The Kill-A-Watt power monitor uses
standard electrical plugs and outlets, but
standard precautions should be used
whenever working near 120 VAC. Make
sure all plugs are fully connected. Don’t
touch the prongs as you plug or unplug a
connection.
Lab Preparation
1. The lab instructor will set up the devices
and power meters around the lab.
2. You may work individually or in groups
of two or three, but all students must
verify the measurements, examine the
ratings stickers on the units under test
(UUT), and record the values on their
worksheets.
K1. Identify basic electrical quantities and
units
K2. Compare measured data with rated
values
K3. Compare power consumption of
common devices
S1. Record data from a power monitor
S2. Enter data into a pre-defined
spreadsheet form
A1. Appreciate the impact of individual
devices on a home’s total energy
usage.
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ENGR 43
Lab Activity
Student Guide
Task #1 – Electrical Measurements
and Units
5.
Review the following online presentations to
better understand some of the electrical
quantities and units of measurement that you
will measure in this activity.
1. Power Factor
2. Power Factor Correction
Task #2 – Power Survey
You are assigned the role of a facilities
technician, with the responsibility for
reducing the monthly electricity bill. Your
supervisor has prepared a list of several
devices that are left on during the business
day, and several measurements that she has
requested that you take to determine areas of
potential savings.
1. Download the lab worksheet
Engr43Lab1.xlsx from the GoogleDocs
link. Open the file in Excel and print one
page to use as a worksheet as you collect
the data.
2. Locate each of the stations where a KillA-Watt power monitor is connected to a
unit under test (UUT). Note that the
three lamps and the solder fume fan are
all at the same station, each with an
individual Kill-A-Watt, and a fifth KillA-Watt connected to the outlet strip
powering the four UUTs.
3. Move among the stations and collect the
data as shown on the worksheet. You
may go to the devices in any sequence.
4. For each of the listed UUT, locate the
electrical rating sticker (usually near the
AC power cord, or stamped on the
lamps). Record the volt, amp, and/or
watt ratings for the device. Note that
many times one of the values will not be
listed. In the case of power supplies and
chargers, be sure to record the input
Lab 1 – What’s a Watt?
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7.
8.
2
(AC) ratings and not the output (DC)
ratings.
For each UUT and for the listed
conditions (“on,” “high,” “low,” etc.),
read the measured value from the Kill-AWatt. Push the button under the Kill-AWatt LCD display to select each value.
The watts/VA, Hz/PF, and KWH/Hour
buttons are toggle functions. Press once
to select function, and a second time to
see the other value. Be sure to look at the
LCD display to see which units are
being displayed:
Volts: The source voltage supplied to the
UUT, typically 115 to 120 Volts
Amps: The current flowing through the
UUT, displayed in Amps
Watts: The power consumed by the
UUT, displayed in Watts
VA: The apparent power, which is the
voltage multiplied by the amperage, in
VA
Hz: The frequency (cycles per second)
of the AC voltage, displayed in Hertz
PF: The power factor for the UUT
KWH: Kilowatt-hours, which is the total
energy consumed.
Hour: Total hours:minutes that the KillA-Watt has been monitoring the UUT.
After you have collected all the data in
Table 1, Re-open the Excel file
Engr43Lab1.xlsx.
Copy your handwritten data into the
cells in Table 1. Notice that some of the
values are automatically copied into
Table 2. This happens because Table 2
uses a cell reference to copy the data
from Table 1. Table 2 also uses a
function to add the values of the four
UUT.
The data from Table 2 are used to
produce the chart comparing the real
power and apparent power for the UUTs
connected to the outlet strip. Compare
this with the power factor, real power,
and apparent power for the outlet strip.
© 2012
ENGR 43
Lab Activity
Student Guide
9. After you have entered all the data, print
your worksheet, then save your file on
your USB drive.
10. Refer to your data worksheet and answer
the questions in the Power Survey
Report.
Deliverable(s)
Print and turn in your completed Excel
Worksheet. Answer the questions in the
Power Survey Report (below). Save your
work in your Lab Activity Binder.
Lab 1 Power Survey Report
Wattage
Which devices consume the most power? Which consume the least? What recommendations
would you make for reducing the monthly power bill in a facility that has several of all of these
devices? (Hint: If you left the Kill-a-Watt monitors connected for several days, what
measurement(s) may be more useful than power for making your recommendations)
There have been several public-service ads asking people to unplug their cell phone chargers
when not charging the phone. How effective do you think this would be? What other actions
could be more effective in saving power?
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ENGR 43
Lab Activity
Student Guide
Total Power Usage
Compare the total watts and VA from the outlet strip power monitor. How does it compare with
the added total wattage and VA of the four individual UUTs? Can you explain the significance of
the data? (Hint: It’s related to the Power Factor measurements.)
Rated vs. Measured Values
How do the rated values compare with your measured values?
Why do the rating labels often only list amperage or wattage? Why is voltage never omitted?
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© 2012