Figure 10.f. 10.c.
Power
Power
I
I
V
V
Pure inductor
Pure capacitor
FIGURE 10.2
2.f. 10. circuit the power consumed given the product the volt-
age and current, because d.f. The power waveform obtained from
the product and every instant the cycle.6, the p.5, say that the p.05
π
Ω
∴
π
Ω
For (b):
Z X
Z
2
2 2
( )
(100 (53. is
lagging, and the current leads the voltage shown Fig.c.8
Waveform for the a.
If the current lags the voltage shown Fig.) defined the cosine the phase angle between the
current and voltage:
p. cos
φ
Definition
Power factor (p. can seen that the
power waveform reverses every quarter cycle, indicating that energy alter-
nately being fed into and taken out the inductor and capacitor. cos R
T
φ
R
Z
V
V
The electrical power circuit the product the instantaneous values of
the voltage and current.f.f. 10.c.Alternating current theory and electrical machines
201
For (a):
X
fC
X
C
C 6
1
2
( )
1
2 50Hz F
53.f. When con-
sidered over one complete cycle, the positive and negative portions are equal,
showing that the average power consumed pure inductor capacitor is
zero.2
Ω
∴ Ω
Ω
For (c):
I
V
Z
I
(A)
230 V
113.) defined the
cosine the phase angle between
the current and voltage.8 shows the voltage and current waveform
for pure inductor and pure capacitor.05 113.This shows that inductors and capacitors store energy during one part of
the voltage cycle and feed back into the supply later the cycle. is
said leading. Inductors
store energy magnetic field and capacitors electric field. power purely inductive
and purely capacitive circuits. From the trigonometry the impedance triangle shown
in Fig.7, p.
.
In electric circuit more power taken from the supply than fed back
into it, since some power dissipated the resistance the circuit, and
therefore:
P )
In any d. circuit voltage and current are phase. also equal to:
p.f.03A
∴
Ω
Power and power factor
Power factor (p
