The effective armature resistance of a 3-phase, star connected, 500 kVA, 1100 V alternator is 0.1 per phase. Field current of 30 A produces the open circuit voltage of 400 V (line value) and the short circuit current of 200 A. Calculate the full load regulation at 0.8 power factor lagging.

Discuss the concept of power factor in AC circuits and its significance in power distribution.

A three-phase 25-kVA, 480-V, 60-Hz alternator, operating under balanced steady state conditions, supplies a line current of 20 A per phase at a 0.8 lagging power factor and at rated voltage. Determine the power triangle for this operating condition.

Determine the efficiency of a 1200 kVA, 4160 Volts, 3-phase, Y-connected alternator, which operates at rated output with a power factor of 83%. The DC armature resistance at 70 degree C between terminals is 0.10 ohm. The field takes 75 amps at 115 Volts from the exciter equipment. Friction and windage losses are 15 kW, iron loss is 40 kW and stray load losses is 1.75 kW. Assume the effective armature winding resistance is 1.65 times the DC value.

A 2 MVA, 2.3 kV, 3 phase Y connected alternator operates at rated kVA at a PF of 80%. The DC armature winding resistance between terminals is 0.08 ohms. The field takes 70 A at 125 V from an exciter equipment. Friction and windage loss is 20 kW, iron losses 36 kW and stray load losses are 2 kW. Calculate the efficiency of the alternator. Assume the effective armature winding resistance 12% of the DC resistance.

An 11-kV, 1000-kVA, 3-phase, Y-connected alternator has a resistance of 2 0 per phase. The open-circuit and full-load zero power factor characteristics are given below. Find the voltage regulation of the alternator for full load current at 0.8 p.f. lagging by Potier method? Field current 40 50 110 140 180 (A) O.C.C. 3350 4000 7200 7900 8650 voltage(V/ph) zero p.f. load 860 4900 6000 7200 voltage(V/ph)