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1) A three-phase 16-pole alternator has a star-connected winding with 144 slots and 10 conductors per slot. The flux per pole is 0.03 Wb, sinusoidally distributed, and the speed is 375 rpm. Assuming a pitch factor of Kp=1, calculate i. the frequency ii. line induced e.m.f.
2) A 4-pole, three-phase, 50 Hz, star-connected alternator has 60 slots with 4 conductors per slot. Coils are short-pitched by 3 slots. If the phase spread is 600, find the line voltage induced for a flux per pole of 0.943 Wb distributed sinusoidally. All the turns per phase are in series.
3) A 500 kVA, three-phase star-connected alternator has a rated line-to-line voltage of 3300 V. The resistance and synchronous reactance per phase are 0.3 Ω and 4 Ω respectively. Calculate the line value of the e.m.f generated at full-load 0.8 power factor lagging.
4) A 2000 kVA, 11 kV, three-phase star-connected alternator has an armature resistance of 0.3 Ω and synchronous reactance of 5 Ω per phase. It delivers full load current at 0.8 lagging power factor at rated voltage. Compute the terminal voltage for the same excitation and load current at 0.8 power factor leading.
5) A three-phase star-connected alternator is rated at 1600 KVA, 13,500 V. The armature resistance and synchronous reactance are 1.5 Ω and 30 Ω respectively per phase. Calculate the percentage regulation for a load of 1280 Kw at 0.8 leading power factor.
6) In a 50 kVA star-connected, 440 V, three-phase, 50 Hz alternator, the effective armature resistance is 0.25 Ω per phase. The synchronous reactance is 3.2 Ω per phase, and the leakage reactance is 0.5 Ω per phase. Determine at rated load and unity power factor, the no-load voltage and percentage voltage regulation.