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EE 221 Circuits Laboratory II

Laboratory Report

Laboratory Experiment No.2

Reactance, Magnitude and Phase

Written by: Eric Krage Date Performed: Thursday, January27

Lab Partner: Reece C. Lab Section: 2Thursday. 9:00-12:00 am

Instructor: Mr. Rabindra Maharjan

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Introduction:

In this laboratory procedure the goal is to become more proficient in using the fluke 41 power

analyzer to measure phase angle lag and lead. These types of measurements would be made to

R, L, & C circuits as well as RLC circuits. The measurements made would include the reactance

inductance as well as the capacitance in the RC circuit.

Apparatus:

Power Bench 2 (PWB)

ALB Station 2 (automated load bank)

2 Fluke 41 (Type of digital multi-meter that measure current voltage power and more)

Simpson Bench Mate (Source of the power benchs power which measures current & voltage)

Lab View (Computer program which was used to drive the ALB & display values of W, I, V)

MMI (Man Machine Interface acts as distribution center)

2 Sets of cables.

Variable Capacitor bank.

Inductor variable

Procedure:

Part A:

Inductive reactance is given by Eq. 1 in where Eq. 2 gives the frequency. The frequency f is

60Hz the complex reactance is given by Eq. 3 in .

Then with the power off the 120 is connected to the reactance. Setting the reactance to

50 answer the following questions.

a) What is the inductance for this value of reactive ohms?

b) If , what should the line current be, assuming that the voltage is 120 Vrms?

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c) If we assume that the inductor is ideal, what should the phase shift between the currentwith respect to the voltage be, given that ?

d) Assuming the inductor is ideal, what should the power in Watts to the inductor be?

Inductance Line Current Phase Shift vs. V Power Watts

Theoretical 0.1329297 2.4 2.4

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This figure is an exact match to how the circuit was set up. But instead of using a common

ground for all the components they each had their own respective ground so that the values of

phase angle current a power can be measured respectively for each component.

Starting with the power off the circuit above was connected then the ALB and power bench

where connected together. Then the power was turned on and the ALB set to 200 watts. The

source voltage, current, inductor, capacitor and ALB currents where measured and displayed in

the table below.I believe that the sum of the inductor, capacitor, and ALB currents should be

equal to the source power. But in this case since the capacitor and inductor act as power

sources this does not hold true with simple KVL. When the power probe is moved to the place

in front of the inductor the measurement should be the total power in the circuit. The phase

shift of the source current was found to be 47 degrees.

Source Inductor Capacitor ALB

Voltage 120.9 120.8 121.0 121.0

Current 2.73 2.47 4.28 1.74

Power 220 21 -.02 224

Phase angle 47 -86 92 4

Compared to the value of the ALB power that was set by the VI it is off but compared to the

fluke meter it is nearly identical.

ALB VI Calculated

.89% 3.2% 225.1 % difference Vs.

calculated

The value measured by the fluke is closest and this is what would be expected due to the exact

calculation of the power given the current and voltage of the source. The values from steps 3

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and 5 can be assumed as an ideal circuit because no true ideal circuit can be formed due to

imperfections in the materials .

Results and Analysis:

Calculations:

Inductive Reactance Eq1

Complex Reactance Eq2

Capacitive Reactance Eq3

Complex reactance Eq4

Ohms Law Eq5

Power Eq. 6

Percent ErrorEq. 7

Propagation of ErrorEq. 8

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So error is

Conclusion:

This lab tested our ability to successfully set up the PWB and connect it through Lab View to the

ALB by the MMI. And taught us how to set up the capacitor and inductor with the AC power

source. By doing so the RLC circuit was set up in shunt and values where found for the source

current, voltage, and power. Then thorough kirchoffs laws we found the total supplied power

and voltage.