Question

Circuit 375 - 1 180 mh mst 60 H2 1. Calculate the complex power absorbed by the load and draw the power triangle 2. Calculate the power factor of the load 3. Calculate the value of capacitor required to give a power factor of 1. 4. Calculate the value of capacitor required to give a power factor> 0.95 (lagging)

Answer 1

X_L = JWL = j times 2 times Pi times 60 times 180 times 10^-3 X_L = j67.858 Ohm I = V/Z = 60/75 + j67.858 = 60/101.142 angle 42.13 I = (0.593 angle -42 .13)_4 1 complex power observed by the load = V I = 60 times (0.593 angle -42 .13)^* = (35.593 angle 42.13) complex power = (26.397 + j23.876) VA 2 power factor Cos Phi_1 = Cos 42.13 Cos Phi_1 = 0.742 lag 3 Required power factor Cos Phi_2 = 1 theta_1 sh = p [tan PHi_1 tan Phi_2] theta_1 sh = 26.397 [tan 42.13 - tan 0] theta_1 sh = 23.876 VAR = V^2 /X_c x_c = (60)^2/23.876 = 150.775 Ohm But x_c = 1/2Pi fc implies c = 1/2 Pi f X_c c = 1/2 times PI times 60 times 150.775 = 17.593 mu F 4 Cos Phi_3 = 0.95 implies