Intoduction to Electrical Engineering Tut 2

7/28/2019 Intoduction to Electrical Engineering Tut 2

1/12

Introduction to Electrical Engineering

Shiv Nadar University, School of Engineering, Department of Electrical Engineering Page 1

Tutorial 2 (AC Circuits and 3 Phase)

1. For the oscilloscope display:a. Determine the period of each waveform.

b. Determine the frequency of each waveform.

c. Find the rms value of each waveform.d. Determine the phase shift between the two waveforms and which leads or lags.

2. The voltage across a 1-mF capacitor is 30 sin 200t. What is the sinusoidal expression forthe current?

3. Determine the sinusoidal expression for the source voltage and for currents i1 and i2

4. Perform the following operations and give your answer in rectangular form for a,b and cand in polar form for d and e


2/12



5. Find the sinusoidal expression for the voltage va ifein =120 sin(wt+30)

Vb= 30 sin (wt+60)

Vc=40sin (wt+120)

6. Find the sinusoidal expression for the current i1 for the system, ifis=0.018sin (377t+180)

i2=0.008sin (377t-180)i3=2i2

7.


3/12



8.

9. a. Find the total admittance YT in polar form.b. Draw the admittance diagram.c. Find the value of C in microfarads and L in henries.

d. Find the voltage E and currents IR, IL, and IC in phasor form.e. Draw the phasor diagram of the currents Is, IR, IL, and IC, and the voltage E.

f. Verify Kirchhoffs current law at one node.

g. Find the average power delivered to the circuit.h. Find the power factor of the circuit, and indicate whether it is leading or lagging.

i. Find the sinusoidal expressions for the currents and voltage.


4/12



j. Plot the waveforms for the currents and voltage on the same set of axes.

10.

a. Calculate E, IR, and IL in phasor form.

b. Calculate the total power factor, and indicate whether it is leading or lagging.

c. Calculate the average power delivered to the circuit.

d. Draw the admittance diagram.e. Draw the phasor diagram of the currents Is, IR, and IL, and the voltage E.

f. Find the current IC for each capacitor using only Kirchhoffs current law.

g. Find the series circuit of one resistive and reactive element that will have the sameimpedance as the original circuit.

11.Find the element or elements that must be in the closed container of Fig to satisfy thefollowing conditions. (Find the simplest parallel circuit that will satisfy the indicatedconditions.)

a. Average power to the circuit is 3000 W.

b. Circuit has a lagging power factor.


5/12



12.

13.

Find the unknown quantities marked in the circuit diagram.

14.Find I1, V1 and average power delivered to network


6/12



15.

a.Find the total impedance ZT and the admittance YT.

b. Find the source current Is in phasor form.

c. Find the currents I1 and I2 in phasor form.

d. Find the voltages V1 and Vab in phasor form.e. Find the average power delivered to the network.

f. Find the power factor of the network, and indicate whether it is leading or lagging.

16.a. Find the total impedanceb. Find V1, I1 and Is

17.Find I1


7/12



18.

19.

a. Find total P, Q and S, Power factor.b. Draw the power Triangle and find Is.

20.

a. Find the average, reactive, and apparent power for the 20 ohm resistor.b. Repeat part (a) for the 10 ohm inductive reactance.c. Find the total number of watts, volt-amperes reactive, and volt-amperes, and the

power factor Fp.

d. Find the current Is.


8/12



21.

a. Find the average power delivered to each element.b. Find the reactive power for each element.c. Find the apparent power for each element.d. Find the total number of watts, volt-amperes reactive, and volt-amperes, and the

power factor of the circuit.

e. Sketch the power triangle.f. Find the energy dissipated by the resistor over one full cycle of the input voltage.g. Find the energy stored or returned by the capacitor and the inductor over one half-

cycle of the power curve for each.

22.

23.a. Find the total number of watts, volt-amperes reactive, and volt-amperes, and pf.b. Find the current Is.c. Find the type of elements and their impedance in each box. (Assume that the elements

within each box are in series.)


9/12



24.

a. Find the total number of watts, volt-amperes reactive, and volt-amperes, and pf.

b. Find the voltage E.

c. Find the type of elements and their impedance in each box. (Assume that the elements

within each box are in series.)

25.

The phase sequence for the Y-Y system of Fig. is ABC.a. Find the angles 2 and 3 for the specified phase sequence.b. Find the voltage across each phase impedance in phasor form.

c. Find the current through each phase impedance in phasor form.d. Draw the phasor diagram of the currents found in part (c), and show that their phasor

sum is zero.

e. Find the magnitude of the line currents.

f. Find the magnitude of the line voltages.


10/12



26.

Find the magnitude of the unknown voltages and currents.27.

a. Find the magnitude and angle associated with the voltages EAN, EBN, and ECN.

b. Determine the magnitude and angle associated with each phase current of the load: Ian,Ibn, and Icn.

c. Find the magnitude and phase angle of each line current: IAa, IBb, and ICc.

d. Determine the magnitude and phase angle of the voltage across each phase of the load:Van, Vbn, and Vcn.


11/12



28.

For the Delta-connected load of Fig:

a. Find the magnitude and angle of each phase current Iab, Ibc, and Ica.

b. Calculate the magnitude and angle of each line current IAa, IBb, and ICc.c. Determine the magnitude and angle of the voltages EAB, EBC, and ECA.

29.

Find the total watts, Volt amperes reactive, volt amperes and power factor.

30.For the three wire system, properly connect a second wattmeter so that two measure thetotal power delivered to the load.


12/12



31.Find the magnitude and angle of the phase currents, line currents. Determine reading ofeach wattmeter and the total power delivered to load.

Documents

Intoduction to Electrical Engineering Tut 2