A 1500kVA , 6.6 kVA 3- phase star connected alternatorhas effective armature resistance of 0.5 ohms per phase and a synchronous reactance of 5 ohms per phase. find the percentage change in terminal voltage when the rated output of 1500 kVA at
i) Unity power factor;
ii)0.8 lagging pf; is switched off.
Assume the speed and excitation remains unchanged.