Electrical Power and Machines
Lecture 1
Dr.Azza Nour El-Dien
Cairo University Faculty of Engineering
Computer Engineering Department
1
Course Content
I. Single Phase Circuits(R,L, C Circuits)
II. 3-Phase Circuits(Star Connection, Delta
III.
Connection, Power Measurement)
IV. Magnetic Circuits(B,H B/H curve, Reluctance
V.
MMF calculation)
VI. Single Phase Transformer(Theory, Equivalent
VII. Circuit, Performance, Regulation ,Efficiency
VIII.
tests)
IX. 3-Phase Induction-Motor (Theory, Construction,
Types, Power flow Diagram, Torque/speed
C/C,Stability, Starting)
2
Current
◎ DC
◎ DC current
◎
◎
AC
Root Mean Square (R MS)
For any sin or cos wave The RMS= Max/2
1-phase AC Circuits
Pure Resistance
Z=R
coil
◎ Z=jwl
Capacitance
Z=1/jwc
Cairo University Faculty of Engineering
Computer Engineering Department
5
Circuit Components
resistance
I inphase
with voltage
coil
capacitor
I lag voltage by I lead voltage
90
by 90
6
Power Factor
https://www.electricaltechnology.org/2013/0
7/power-factor.html
7
Power-Trinagle
Active Power=P (KW), Reactive Power(KVAR), Apparent Power(KVA)
https://www.electricaltechnology.org/2013/0
7/power-factor.html
8
Power Factor Correction
Adding capacitor between the source and the load improves PF
P (KW) does not change , only Q changes and we get the
the corresponding required value of capacitance
9
To calculate the required capacitance to get certain PF
The following formula is used
10