Page 355 - Basic Electrical Engineering

Solution:

We will compare the voltage, n and current, i with the standard form

v = V sin ωt and
m
I = I sin ωt
m

From the data provided

V = 200, I 20, ω = 314
m
m
RMS values,

Figure 3.45

We have represented in Fig. 3.45 the voltage and current with respect to a

common reference axis. The voltage, V is leading the reference axis by π/3°,
i.e., 60°, while current I is leading the reference axis by 30°. The phase angle
between V and I is 30°. The current in the circuit lags the voltage by 30°.

Power factor, cos ϕ = cos 30° = 0.866 lagging
Average power,

P = VI cos ϕ = 141.4 × 0.866