QUESTION I (17 points)

A three-phase, 13.2 kV, 60 Hz, 50 MVA, wye-connected cylindrical-rotor synchronous

generator has an armature reactance of 2.19

per phase. The leakage reactance is 0.137

times the armature reactance. The armature resistance is small enough to be negligible.

Also ignore the saturation. Assume that the generator delivers full-load current at the

rated voltage and 0.8 lagging power factor. Determine the following:

7.

QUESTION II (13 points)

.A three-phase synchronous motor is supplied by 100

A

at a leading power factor of 0.85

from a bus. Determine the following:

a. The current at unity power factor, if the bus voltage is constant. (4 pts)

b. The current at a lagging power factor of 0.85, if the bus voltage is constant. (4 pts)

c. What usually happens to the bus voltage as the power factor becomes more lagging?

(5 pts)

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