For a 300 kVA, 380 V, 3-phase, 50 Hz synchronous generator, the short-circuit test shows that a field current of 2 amper
Posted: Sun May 15, 2022 8:29 pm
For a 300 kVA, 380 V, 3-phase, 50 Hz synchronous generator, the short-circuit test shows that a field current of 2 amperes (DC) at rated rotor speed is needed to produce the rating current (AC) on the armature windings. The open-circuit test shows that a filed current of 3 amperes at rated rotor speed leads a terminal voltage (line-to-line) of 400 volts. The DC test between two lines of the armature terminals gives a reading of 5 amperes (DC) on lines with a voltage of 3 volts (DC) between lines. Assume the AC resistance of the armature coil is 1.2 times that of the DC resistance. Estimate: (i) The per-phase synchronous impedance (resistance and reactance); (ii) The per-phase armature voltage drops (resistive and reactive) at rating current; (iii) The generated voltage (line-to-line) and the field current required when the generator is full-loaded at a power factor of 0.8 lagging. Assume the generator is linearly excited.