1. A 15 kW. 400 V, 3-phase, star-connected synchronous motor has a synchronous impedance of 0.4 + j4 Ω. Find the voltage to which the motor should be excited to give a full-load output at 0.866 leading pf. Assume an armature efficiency of 93%. Also calculate the mechanical power developed.
2. A 3-phase, star-connected synchronous generator is rated at 1200 kVA, l l kV. On short-circuit a field current of 55 A gives full-load current. The OC voltage with the same excitation is 1580 V/phase. Calculate the voltage regulation at
(a) 0.8 lagging and
(b) 0.8 leading pf. Neglect armature resistance.