A 100KVA, 220V, a star-connected alternator is loaded at full load and at 60% pf lagging. The effective AC resistance per phase is 0.01411Ω. If the synchronous reactance is 4.5 times the effect of the armature leakage reactance wherein the later is 0.046 Ω per phase, find (a) the phase voltage that would be generated at the load if the circuit were operating normally (b) What no-load open-circuit phase voltage must be present in order to circulate full-load current in short-circuit state while maintaining the same speed and field current? (c) What is the terminal phase voltage of the alternator when it is under a shorted load condition?
Synchronous Generator
In comparison to an asynchronous generator, it is a machine where the rotor speed is equal to the rotating magnetic field produced by the stator, i.e., mechanical speed is equal to the electrical speed, thus called synchronous, and not asynchronous.
Salient Pole Rotor
Salient pole rotor includes a large number of exposed poles mounted on a magnetic wheel. The construction of a bright pole is as shown in the image on the left. The proposed poles are made of metal laminations. The rotor winding is provided on these poles and is supported by pole shoes.
A 100KVA, 220V, a star-connected alternator is loaded at full load and at 60% pf lagging.
The effective AC resistance per phase is 0.01411Ω. If the synchronous reactance is 4.5
times the effect of the armature leakage reactance wherein the later is 0.046 Ω per
phase, find
(a) the phase voltage that would be generated at the load if the circuit were operating normally
(b) What no-load open-circuit phase voltage must be present in order to circulate full-load current in short-circuit state while maintaining the same speed and field current?
(c) What is the terminal phase voltage of the alternator when it is under a shorted load condition? Give an explanation in support of your response using just one sentence.
The IA phasor should be used as the reference one.
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