
16 Shipboard Electrical Power Systems
Example 1.7
Express the time-domain circuit in Figure E1.7(a) in the phasor domain with imped-
ances in ohms. Then, determine the current phasor I
˜
and the average power.
75 μF
12 Ω 12 Ω
340 cos(314t) V
60 Hz
80 mH
240 V
rms
–j 42.46 Ω
j 25.12 Ω
(a) (b)
SOLUTION
First, the voltage phasor’s rms value = 340 ÷ √2 = 240∠0° V (Reference for angle).
Angular frequency ω = 314, which gives f = ω/2 π = 50 Hz.
The loop impedance of the series R-L-C circuit in (a) is
Z j
j
= + −
= + −
−
12 314 0 080
1
314 75 10
12 25 12 4
6
×
× ×
.
( . 22 46 12 17 34 21 09 55 3. ) . . .= − = ∠ −j ohms
The phasor-domain circuit is shown in (b), from wh ...