This document contains lecture notes for a Circuit Analysis course taught by Dr. Raja Masood Larik. It includes information about the instructor's educational background and research interests. The notes cover topics like polyphase circuits, three-phase generation and different three-phase connections including wye-wye, delta-delta, wye-delta and delta-wye. Diagrams are provided to illustrate balanced and unbalanced systems as well as how voltage and current values differ between line and phase quantities depending on the type of connection.

1. Circuit Analysis (EE-126)
Engr. Dr. Raja Masood Larik
rmlarik@neduet.edu.pk
• Class code: ak3xqba
MEET LINK: https://meet.google.com/lookup/g6rnx4hvb2
• B.E (Electrical Engineering), NED University of Engineering & Technology Karachi, Sindh-Pakistan. 1998.
• M.Engg (Electrical Engineering, CGPA 3.45/4.00), NED University of Engineering& Technology Karachi,
Sindh-Pakistan. 2006
• Doctor of Philosophy (Electrical Engineering) from University Technology Malaysia (UTM). CGPA
3.67/4.00 2019.
• Dr. Larik (Google Scholar Profile)
• https://scholar.google.com/citations?hl=en&user=7z1g_I0AAAAJ
Lecture Notes by Dr.R.M.Larik 1

2. • Engineering Circuit Analysis by William H. Hayt 8th edition (Text Book)
• Fundamentals of Electric circuits by Charles k Alexander (Reference Book)
• Introduction to Electric Circuits by Dorf, Richard C (Reference Book)
• Electric Circuits by Nilsson, James W (Reference BooK)
• Concepts in Electric circuits by Dr.Wasim Naseem (Reference BooK)
• Electric Circuits by Theodore F.Bogart (Reference BooK)
• Electric Circuits by H.Alex Romanowitz (Reference BooK)
Lecture Notes by Dr.R.M.Larik 2

3. 1.Poly Phase Circuits
2.Magnetically Coupled Circuits
3.Two Port Networks
Poly Phase circuits
➢ Balance Three Phase Voltages
➢ Balance Wye Wye Connection
➢ Balanced Wye-Delta Connection
➢ Balanced Delta-Delta Connection
➢ Balanced Delta-Wye Connection
➢ Power in Balanced System
➢ Unbalanced Three Phase Systems
Lecture Notes by Dr.R.M.Larik 3

4. Poly Phase Circuits
Learning Outcomes
▪ Be Familiar with ac single and three phase system
▪ The basics of ac generation from source (Generators/alternator)
▪ The basic difference between balanced and unbalanced three-phase system
▪ To analyse three phase circuits
▪ Connection pattern for three phase i.e. star/delta
Lecture Notes by Dr.R.M.Larik 4

5. AC Generation
Three things must be present in order to produce electrical current:
a) Magnetic field
b) Conductor
c) Relative motion
▪ Conductor cuts lines of magnetic flux, a voltage is induced in the conductor
Direction and Speed are important
Lecture Notes by Dr.R.M.Larik 5

6. What is 1 and 3 Phase?
• 1-Phase (voltage which appears between line to neutral is known as
phase voltage Range from 215-240 V) permissible limit 180V
• Wye or Star Connection
• 3-pahse (Voltage appears between any two lines is known as line
voltage line to line voltage the 3 phase voltage Range from 415-440 V
permissible limit 380V
Lecture Notes by Dr.R.M.Larik 6

7. Single Phase generation
Lecture Notes by Dr.R.M.Larik 7

8. Conductor and magnetic field
have zero degree angle (both
are parallel to each other
Lecture Notes by Dr.R.M.Larik 8

9. Lecture Notes by Dr.R.M.Larik 9

10. Lecture Notes by Dr.R.M.Larik 10

11. Lecture Notes by Dr.R.M.Larik 11

12. Lecture Notes by Dr.R.M.Larik 12

13. Lecture Notes by Dr.R.M.Larik 13

14. Negative Maximum
induced Voltage
Lecture Notes by Dr.R.M.Larik 14

15. Lecture Notes by Dr.R.M.Larik 15

16. No relative motion
between conductor
and magnetic field Lecture Notes by Dr.R.M.Larik 16

17. Lecture Notes by Dr.R.M.Larik 17

18. Advantages and importance of three-phase systems
An AC generator designed to develop a single sinusoidal voltage for each rotation of the shaft (rotor)
is referred to as a single-phase AC generator.
If the number of coils on the rotor is increased in a specified manner, the result is a Polyphase AC
generator, which develops more power than one AC phase voltage per rotation of the rotor
In general, three-phase systems are preferred over single-phase systems for the transmission of
power for many reasons.
1. The instantaneous power in three-phase system can be constant (not pulsating as in a single phase
circuit).
2. For the same transmitted power, three-phase systems consume less wires.
3. The lighter lines are easier to install, and the supporting structures can be less massive and farther
apart.
4. In general, most larger motors are three phase because they are essentially self starting and do not
require a special design or additional starting circuitry.
For the above reasons, most of the power distribution systems in US and over the world, use three-
phase systems.
The first three-phase electrical system was patented in 1882 by John
Hopkinson - British physicist, electrical engineer, Fellow of the Royal Society.
Lecture Notes by Dr.R.M.Larik 18

19. Lecture Notes by Dr.R.M.Larik 19

20. Three Phase generation
Lecture Notes by Dr.R.M.Larik 20

21. Lecture Notes by Dr.R.M.Larik 21

22. WHY WE STUDY 3 PHASE SYSTEM ?
ALL electric power system in the world used 3-
phase system to
GENERATE, TRANSMIT and DISTRIBUTE
One phase, two phase, can be taken from
three phase system rather than generated
independently
Lecture Notes by Dr.R.M.Larik 22

23. Three Phase generation
Lecture Notes by Dr.R.M.Larik 23

24. Lecture Notes by Dr.R.M.Larik 24

25. Important relation of Impedance
Lecture Notes by Dr.R.M.Larik 25

26. Lecture Notes by Dr.R.M.Larik 26

27. What is Phase? What is Line?
The voltage appears between line to neutral is termed as phase voltage
The voltage appears between any two lines (phases) is Line voltage.
We have commonly two types of connection (to connect windings) either we connect in star or delta pattern.
Both connections have certain advantages as well as disadvantages
Lecture Notes by Dr.R.M.Larik 27

28. What is Balanced and Unbalanced 3 Phase System?
Unbalanced 3 Phase System
Each impedance of all phase are dislike for example the impedances are
(4+j2)ohm ,(6+j3)ohm and (8+j5)ohm (Single Phase loads at homes and
Offices)
Balanced 3 Phase System
Balance 3 Phase System each impedance having same value for
example (3+j3)ohm (3+j3)ohm and (3+j3)ohm (3 Phase Induction motor
used in industry)
Lecture Notes by Dr.R.M.Larik 28

29. Lecture Notes by Dr.R.M.Larik 29

30. Single Phase, two and three wire Circuits
Lecture Notes by Dr.R.M.Larik
Two Phase 3 Wire
system ac sources
operates at different
phases
30

31. Three Phase 4 wire Circuits
Lecture Notes by Dr.R.M.Larik 31

32. Three Phase Generation
The three-phase generator has three induction coils placed 120° apart on the stator.
• The three coils have an equal number of turns, the voltage induced across each coil will have the
same peak value, shape and frequency. Internal impedance of a generator is usually inductive
(due to the use of coils).
Lecture Notes by Dr.R.M.Larik 32

33. Wye Connected Generator
Lecture Notes by Dr.R.M.Larik 33

34. Delta Connected Generator
Lecture Notes by Dr.R.M.Larik
The Line voltages are equals to
phase voltages while the line
current equals Under root 3
times phase current
34

35. Balanced 3 Phase Loads
Lecture Notes by Dr.R.M.Larik 35

36. Balanced 3 Phase Voltages
Lecture Notes by Dr.R.M.Larik 36

37. Balanced 3 Phase Voltages
Lecture Notes by Dr.R.M.Larik 37

38. 3 Phase Connections
Lecture Notes by Dr.R.M.Larik 38

39. 3 Phase Connections
Lecture Notes by Dr.R.M.Larik 39

40. Wye Connection
Lecture Notes by Dr.R.M.Larik 40

41. Balanced Y-Y Connections
Lecture Notes by Dr.R.M.Larik
• A balanced Y-Y system, showing the source, line and load impedances.
41

42. Balanced Wye Wye Connection
Lecture Notes by Dr.R.M.Larik 42

43. Balanced Wye Wye Connection
Lecture Notes by Dr.R.M.Larik 43

44. Wye –Delta Connection
Lecture Notes by Dr.R.M.Larik 44

45. Delta Delta Connection
Lecture Notes by Dr.R.M.Larik 45

46. Delta-Wye Connection
Lecture Notes by Dr.R.M.Larik 46