4.2 A 13.8-kV, 50-MVA, 0.9-power-factor-lagging, 60-Hz, four-pole Y-connected synchronous generator has a synchronous reactance of 2.5 Q and an armature resistance of 0.2N. At 60 Hz, its friction and...

Extracted text: 4.2 A 13.8-kV, 50-MVA, 0.9-power-factor-lagging, 60-Hz, four-pole Y-connected synchronous generator has a synchronous reactance of 2.5 Q and an armature resistance of 0.2N. At 60 Hz, its friction and windage losses are 1 MW, and its core losses are 1.5 MW. The field circuit has a dc voltage of 120 V, and the maximum I, is 10 A. The current of the field circuit is adjustable over the range from 0 to 10 A. The OCC of this generator is shown in Figure P4-1. cos (6)-0.S 4.3 Assume that the field current of the generator in Problem 4-2 has been adjusted to a value of 5 A. (a) What will the terminal voltage of this generator be if it is connected to a A-connected load with an impedance of 24Z25° 2? (b) Sketch the phasor diagram of this generator. (c) What is the efficiency of the generator at these conditions? (d) Now assume that another identical A-connected load is to be paralleled with the first one. What happens to the phasor diagram for the generator? (e) What is the new terminal voltage after the load has been added? O What must be done to restore the terminal voltage to its original value? it characteristic


Extracted text: I value? it characteristic 18 16 14 12 10 4 0. 1 3 4 6. 7. 8. 6. 10 Field current (A) 20 69 00 Open-circuit voltage (kV)