Khawaja Fareed University of Engineering &
Information Technology (KFUEIT) Rahim Yar Khan
Department of Electrical Engineering
Instructor name: ____________________ Dated: ________________
Semester: __________________________ Session: _______________
EE-171: Instrumentation and Measurement LAB
LAB7: TO MEASURE THE POWER AND POWER FACTOR BY THREE
AMMETER METHOD
Name Reg. No Report Viva Marks / Total/15
Marks / 10 5
__________________________
Instructor Signature
EE-171: Instrumentation and Measurement LAB Page 1
Khawaja Fareed University of Engineering &
Information Technology (KFUEIT) Rahim Yar Khan
To Measure the Power and Power Factor by three Ammeter method
Objective:-
To Measure the Power and Power Factor by three Ammeter method.
Conduct of Lab
The students are required to work in groups of three to four; each student must attempt to
understand and use the laboratory set-up and conduct at least one or two parts of the requirement
experimentation. The lab attendants and Teaching Assistants will be available to assist the
students.
In case some aspect of the lab experiment is not understood the students are advised to seek help
from the teacher, the lab attendant.
Apparatus:-
1) AC Supply
2) Different Wires or Connectors
3) Bread Board
4) Different kind of Potentiometers
5) Ammeters and voltmeter
Theory:-
A On analyzing the given circuit, the total current I1 is divided into I2 & I3. I 2 current is
passing through resistor therefore it is in phase with applied voltage, while I3 is passing
through inductor therefore it is lagged by angle φ with respect to applied voltage.
Graphically it can be represented as:
A A
A R
R L
EE-171: Instrumentation and Measurement LAB Page 2
Khawaja Fareed University of Engineering &
Information Technology (KFUEIT) Rahim Yar Khan
Resolve I into components & consider Δ ABC.
(𝐼1 )2 = (𝐼2 + 𝐼3 𝑐𝑜𝑠𝜑)2 + (𝐼3 𝑠𝑖𝑛𝜑)2
(𝐼1 )2 = 𝐼22 + 2𝐼2 𝐼3 𝑐𝑜𝑠𝜑 + +𝐼32 𝑐𝑜𝑠 2 𝜑 + (𝐼3 𝑠𝑖𝑛𝜑)2
𝐼12 − 𝐼22 = 2𝐼2 𝐼3 𝑐𝑜𝑠𝜑 + 𝐼32 (𝑐𝑜𝑠 2 𝜑 + 𝑠𝑖𝑛2 𝜑)
Now,
𝑐𝑜𝑠𝜑 = (𝐼12 −𝐼22 − 𝐼32 )/2𝐼2 𝐼3
Now again consider above equation
2𝐼2 𝐼3 𝑐𝑜𝑠𝜑 = (𝐼12 −𝐼22 − 𝐼32 )
2(𝑉/𝑅)𝐼3 𝑐𝑜𝑠𝜑 = (𝐼12 −𝐼22 − 𝐼32 )
(𝐼12 −𝐼22 − 𝐼32 )𝑅
𝑉𝐼3 𝑐𝑜𝑠𝜑 =
2
(𝐼12 −𝐼22 − 𝐼32 )𝑅
𝑃=
2
(𝐼12 −𝐼22 −𝐼32 )𝑅
Real Power= & Where R=150V/𝐼2
2
Procedure :-
1) Construct the circuit by placing the components as shown in figure.
2) Apply the input
3) Note down the values of current and voltage
4) Find the real power using formulae
EE-171: Instrumentation and Measurement LAB Page 3
Khawaja Fareed University of Engineering &
Information Technology (KFUEIT) Rahim Yar Khan
Observation and calculation:
Sr. No I1 I2 I3 V P
Conclusions & Discussion
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_____________________________________________________________________________________
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EE-171: Instrumentation and Measurement LAB Page 4
Khawaja Fareed University of Engineering &
Information Technology (KFUEIT) Rahim Yar Khan
Each student is required to perform the lab and submit the following Performa along with the lab report.
1= Unsatisfactory, 2= Fair, 3= Satisfactory, 4= Very good, 5= Excellent
Questions Rating Remarks
(1 to 5)
1. To what extent did you learn on the material in the lab?
2. Are you able to apply knowledge gained in the lab to
similar problems?
3. Are you able to analyze and interpret data recorded in the
lab?
4. Are you able to identify, formulate and solve electrical
engineering problems based on the knowledge acquired in
the lab.?
5. Can you design a system, component or process to fulfill
certain specifications based on the knowledge acquired in
the lab?
6. Were you able to function as a group in the lab?
7. Were you able to interpret effectively the procedures and
questions asked in the lab?
8. Comment whether your work in the lab has an impact on
the society.
EE-171: Instrumentation and Measurement LAB Page 5
Khawaja Fareed University of Engineering &
Information Technology (KFUEIT) Rahim Yar Khan
Additional Comments (if any):
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EE-171: Instrumentation and Measurement LAB Page 6
