Answer to Question #201834 in Electrical Engineering for tala

Question

A three-phase system has an effective line

voltage of 240 V, and is connected to a

balanced delta load which draws 5 kW at a

power factor of 0.8, then the line current is:

Select one:

a. 13.88 A

b. 16.4 A

c. 12.89 A

d. 15.04 A

e. 12.03 A

Answer 1

Since 

$PF = \frac{P}{S} \implies S= \frac{ 5000}{0.8} - 6250 VA$ .

From the formula for apparent power 

$S = 3U_pI_p \implies I_p=\frac{ 6250}{3*240}= 8.681A.$  

Line current is $\sqrt{3}$ times greater then phase current 

$I_L=\sqrt{3}*8.681 =15.035 A$ (Option D)