1. At a location in Europe, it is necessary to supply 300 kW of 60-Hz power. The only power sources available operate at 50 Hz. It is decided to generate the power by means of a motor-generator set consisting of a synchronous motor driving a synchronous generator. How many poles should each of the two machines have in order to convert 50-Hz power to 60-Hz power?
2. A 480-V 200-kVA 0.8-power-factor-lagging 60-Hz two-pole Y-connected synchronous generator has a synchronous reactance of 0.25 W and an armature resistance of 0.03 W. At 60 Hz, its friction and windage losses are 6 kW, and its core losses are 4 kW. The field circuit has a dc voltage of 200 V, and the maximum IF is 10 A. The resistance of the field circuit is adjustable over the range from 20 to 200 W. The OCC of this generator is shown in Figure P5-1.
(a) How much field current is required to make VT equal to 480 V when the generator is running at no load?
(b) What is the internal generated voltage of this machine at rated conditions?
(c) How much field current is required to make VT equal to 480 V when the generator is running at rated conditions?
(d) How much power and torque must the generator's prime mover be capable of supplying?
