KING FAHD UNIVERSITY OF PETROLEUM & MINERALS
Department of Electrical Engineering
EE361: Electrical Energy Engineering- LAB
Semester: 232
Student Name AHMED HOSAMELDIN MOHAMED
Student ID # 201927410
Section # 56
Experiment No 1
Experiment Name
Introduction To CASSY Lab Software
Expt. Table No 5
Date 31/ 1/ 2024
Instructor Name Dr. FIROZ AHMAD
Objectives:
• To learn and experiment the measurement of electrical variables through the digital technology
Cassy data acquisition in connection with Cassy Lab computer interface.
• To measure, display and record DC and AC quantities then extract subsequent quantities online
and offline.
• To plot and analyze the results.
Introduction:
This laboratory exercise represents the inaugural experiment in course EE 361. It serves as a
foundational introduction to the course, encompassing an overview of laboratory safety protocols,
policy guidelines, grading criteria, and a comprehensive outline of the educational objectives and
core competencies to be developed throughout the course. Additionally, this session delineates the
primary instruments and tools that will be utilized, with a particular emphasis on the Cassylab2
software.
The experimental component of this session was bifurcated into two distinct parts. The initial
segment entailed the measurement of impedance in two different load scenarios: a purely resistive
load and an inductive load. This was accomplished using a digital multimeter. The impedance (Z)
of a load is a fundamental concept in electrical engineering, represented mathematically as:
Z = R + jX
(1)
where (R) is the resistance and (X) is the reactance. For a purely resistive load, the reactance (X)
is zero, thus simplifying the equation to (Z = R). In contrast, an inductive load introduces
inductance (L), altering the reactance component.
The second part of the experiment focused on quantifying electrical variables - specifically voltage
(V) and current (I) - for both the resistive and inductive loads. This was achieved by applying
Ohm's Law, a fundamental principle in electrical engineering, defined as:
V=ZxI
(2)
Subsequently, the Cassylab2 software was employed to graphically represent the relationship
between voltage and current, plotting (V) against (I), to elucidate the underlying electrical
characteristics of the loads. This graphical analysis serves as a visual interpretation of Ohm's Law
in practical scenarios. The detailed methodology, results, and analytical discussions of these
experiments are elaborated upon in the subsequent sections of this report.
Results and Analyses:
Table 1: Load Resistance measurements
Resistance control
Position (%)
100%
0%
Load1()
1.069K
23.5
Load2()
1.028K
23.9
Load3()
1.058K
23.6
Table 2: Inductance internal series resistances measurements
Inductance Value(H),
Current Rating (A)
1.2H, 0.5A
Load1()
21
Load2()
21.1
Load3()
20.9
A. DC Measurement:
Table 3: Recorded and calculated data for DC
𝒏
1
2
3
4
5
6
7
8
𝑹𝒆𝒔𝒊𝒔𝒕𝒊𝒗𝒆 𝒍𝒐𝒂𝒅 (%)
100
90
80
70
60
50
40
30
𝑽𝑳 (𝑽) 𝑰𝑳 (𝑨)
99.5
0.31
99.5
0.33
99.5
0.37
99.5
0.425
99.5
0.49
99.5
0.575
100
0.71
100
1.02
R(𝛀)
Power (W)
320.97
30.845
301.52
32.835
268.92
36.815
234.12
42.2875
203.06
48.755
173.04
57.2125
140.85
71
98.04
102
𝒄𝒂𝒍𝒖𝒄𝒂𝒍𝒕𝒊𝒏𝒈 𝒊𝒕𝒉𝒆𝒓 𝒑𝒓𝒂𝒎𝒕𝒆𝒓:
𝐸𝑞(3):
𝐸𝑞(4):
𝑉
𝐼
𝑃 = 𝑉𝐼𝑐𝑜𝑠(∅),
𝑅=
𝑐𝑜𝑠(∅) = 1 𝑎𝑠 𝐷𝐶 𝑏𝑒𝑒𝑛 𝑎𝑝𝑝𝑙𝑖𝑒𝑑
Figure 1: Graph of voltage & current vs n for DC
Note regarding to Figure 1: In the experiment where the voltage was held constant at 100
volts, a decrease in the resistive load from 100 ohms demonstrated an increase in current,
in accordance with Ohm's Law 𝑉 = 𝐼 × 𝑅 . This observation confirms the inverse
relationship between current and resistance; as resistance decreases, current increases,
provided the voltage remains unchanged. This result aligns with the theoretical predictions
of Ohm's Law, illustrating the fundamental principles governing electrical circuits.
Table 4: Current vs Power of DC recoded data
𝑰𝑳 (𝑨)
0.31
0.33
0.37
0.425
0.49
0.575
0.71
1.02
P(𝑾)
30.845
32.835
36.815
42.288
48.755
57.213
71
102
Figure 2: Graph of Power vs current for DC
For finding the slop of the power vs current we applied to horizontal line using set marker and
after that using draw slop tringle tool then figure 3 will show as follow:
Figure 3: Finding slop of the Power vs current in DC
𝑚 is representing the slop of the graph
∆𝑃
(P vs I) and it equal 𝑚 = , and for
∆𝐼
that we reach unit of W/A and that
resemble V
As the value above of 𝑚1 = 99.5𝑉 is almost what been adjusted to be set 𝑉𝑠𝑒𝑡 = 100𝑉 and using
hand calculation from Table 4 after choosing two values:
𝑚=
(48.755 − 42.288)𝑤𝑎𝑡𝑡
= 99.49230769𝑉 ≈ 99.5𝑉
(0.49 − 0.425)𝐴
with that it concludes to verify that 𝑉 =
𝑃
𝐼
using the graph above.
Figure 4: The values of the 𝑷𝑳 vs 𝑹𝑳 𝒄𝒖𝒓𝒓𝒆𝒏𝒕.
The relation between PL vs RL is 𝑃𝐿 =
𝑉𝐿2
𝑅𝐿
. The function in terms of RL is 𝑃𝐿 ∝
1
𝑅𝐿
which is a
parabola 1/𝑥.
B. AC Measurements:
Form the recorded data we as AC input, we plot 𝑉𝐿 and 𝐼𝐿 and cos (∅) vs the n and it shoe=ws in
figure 5 below:
Figure 5: Plot of 𝑷𝑳 and 𝑰𝑳 𝒂𝒏𝒅 𝒄𝒐𝒔(∅) vs 𝑹𝑳 𝒄𝒖𝒓𝒓𝒆𝒏𝒕.
Table 5: Recorded and calculated data for AC
R (%90)
100
90
80
70
60
50
40
30
𝒏
1
2
3
4
5
6
7
8
𝑰𝑳 (𝑨)
0.31
0.33
0.37
0.425
0.49
0.575
0.71
1.02
𝑽𝑳 (𝑽)
𝒄𝒐𝒔(∅)
100.8
0.62
100.5
0.65
100.7
0.7
100.5
0.73
100.1
0.77
100.4
0.82
100
0.85
99.8
0.91
It is important to observe in Figure 5 that the voltage, represented in black and aligned with the
left y-axis, remains relatively constant at approximately 100 V. Concurrently, the current and
power factor, depicted in red and blue respectively and corresponding to the right y-axis, exhibit
an increasing trend with the reduction of the resistive load percentage. This graphical
representation underscores the inverse relationship between resistive load and both current and
power factor in the circuit under analysis.
Finding 𝑍𝐿 , it needed to be calculated by using 𝑍𝐿 = √𝑅𝐿2 + (2𝜋𝑓𝐿)2 ,
And 𝑃𝐿 = 𝑉 × 𝐼 × cos(∅) , 𝑎𝑠 cos(∅) = 𝑝𝑓 and R L = 𝐼P2
Then the following table 6 below will demonstrate the critical value:
𝑎𝑠 𝐿 = 1.2𝐻 𝑎𝑛𝑑 𝑓 = 60𝐻𝑧.
Table 6: Recorded and calculated data for 𝒁𝑳 𝒂𝒏𝒅 𝑷𝑳 𝒂𝒏𝒅 𝑹𝑳 𝒗𝒔 𝒏
𝒏
𝒁𝑳 (𝛀)
𝑷𝑳 (𝐖)
𝑹𝑳 (𝛀)
1
545
13.015
303.911
2
546.6
14.113
306.793
3
549.9
15.89
312.641
4
549.1
17.278
311.166
5
545.3
19.725
304.516
6
539.7
22.968
294.266
7
530.8
26.205
277.669
8
509
35.605
233.208
Figure 6: plot of calculated data for 𝒁𝑳 𝒂𝒏𝒅 𝑷𝑳 𝒂𝒏𝒅 𝑹𝑳 𝒗𝒔 𝒏
Measuring power factor for changing the R to {100%,60%,30%} and calculate the delayed
between 𝐼𝐿 𝑎𝑛𝑑 𝑉𝐿
a. at 𝐑 = 𝟏𝟎𝟎%
Figure 7: plot of 𝑽𝑳 and 𝑰𝑳 vs time at 𝑹 = 𝟏𝟎𝟎%
𝜏 = (6.6 − 4.1) 𝑚𝑠 &
𝜃 = 𝜏 × 360 × 𝑓 = 54°
& 𝑝𝑓 = cos(𝜃) = 0.587
𝑹 (%)
𝒑𝒇 𝒐𝒇 𝑴𝒂𝒏𝒖𝒂𝒍
𝒑𝒇 𝒐𝒇 𝒂𝒖𝒕𝒐
𝒆𝒓𝒓𝒐𝒓 (%)
100
0.62
0.587
5.3%
b. at 𝑹 = 𝟔𝟎%
Figure 8: plot of 𝑽𝑳 and 𝑰𝑳 vs time at 𝑹 = 𝟔𝟎%
𝜏 = (6 − 4.1) 𝑚𝑠 &
𝜃 = 𝜏 × 360 × 𝑓 = 41.04°
& 𝑝𝑓 = cos(𝜃) = 0.754
𝑹 (%)
𝒑𝒇 𝒐𝒇 𝑴𝒂𝒏𝒖𝒂𝒍
𝒑𝒇 𝒐𝒇 𝒂𝒖𝒕𝒐
𝒆𝒓𝒓𝒐𝒓 (%)
100
0.73
0.754
3.1%
c. at 𝑹 = 𝟑𝟎%
Figure 9: plot of 𝑽𝑳 and 𝑰𝑳 vs time at 𝑹 = 𝟑𝟎%
𝜏 = (5.2 − 3.9) 𝑚𝑠 &
𝜃 = 𝜏 × 360 × 𝑓 = 28.08°
& 𝑝𝑓 = cos(𝜃) = 0.882
𝑹 (%)
𝒑𝒇 𝒐𝒇 𝑴𝒂𝒏𝒖𝒂𝒍
𝒑𝒇 𝒐𝒇 𝒂𝒖𝒕𝒐
𝒆𝒓𝒓𝒐𝒓 (%)
100
0.91
0.882
3.07%
Conclusion:
This laboratory in EE 361 successfully demonstrated the measurement and
analysis of electrical variables using Cassy data acquisition and Cassylab2
software. The experiments conducted provided a practical understanding of
impedance in resistive and inductive loads, as well as the application of Ohm's
Law in DC and AC circuits. The results showed a consistent voltage around 100
V, while current and power factor increased inversely with the decrease in
resistive load percentage. The use of graphical representations, such as voltagecurrent and power-current plots, effectively illustrated these relationships.
Additionally, the experiment validated theoretical principles by observing the
power factor changes with varying resistive loads and calculating impedance and
power in AC circuits. Overall, the lab reinforced key concepts in electrical
engineering, demonstrating the practical application of theoretical knowledge in
real-world scenarios.