ABSTRACT
ZT = Z1 + Z2 × Z3Z2 + Z3 Determine ZT in polar form, correct to 3 significant figures, when
Z1 = 5.5∠−21◦ ,Z2 = 2.6∠30◦ and Z3 = 4.8∠71◦ (8)
2. For the network shown in Figure RT8.1, determine
(a) the equivalent impedance of the parallel branches (b) the total circuit equivalent impedance (c) current I (d) the circuit phase angle (e) currents I1 and I2 (f) the p.d. across points A and B (g) the p.d. across points B and C (h) the active power developed in the inductive branch (i) the active power developed across the −j10
capacitor (j) the active power developed between points B
and C
Figure RT8.1
(k) the total active power developed in the network (l) the total apparent power developed in the network
(m) the total reactive power developed in the network (27)
3. An inductive load takes a current of 60A at a power factor of 0.643 lagging when connected to a 240V, 50Hz supply. It is required to improve the power factor to 0.80 lagging by connecting a capacitor in parallel with the load. Calculate (a) the new supply current, (b) the capacitor current, and (c) the value of the power factor correction capacitor. Draw the circuit phasor diagram.
