The following information is given for a 300-kW, 600-V, long-shunt compound generator : Shunt field resistance = 75 Ω, armature resistance including brush resistance = 0.03 Ω, commutating field winding resistance = 0.011 Ω, series field resistance = 0.012 Ω, divertor resistance = 0.036 Ω. When the machine is delivering full load, calculate the voltage and power generated by the armature
Power output = 300,000 W
Output current = 300,000/600 = 500 A
Long Shunt DC compound Generator with divertor resistance
Ish = 600/75 = 8 A,
Ia= 500 + 8 = 508 A
Since the series field resistance and divertor resistance are in parallel, their combined resistance is = (0.012 × 0.036) / 0.048 = 0.009 Ω
Total armature circuit resistance = 0.03 – 0.011 + 0.009 = 0.05 Ω
Voltage drop = 508 × 0.05 = 25.4 V
Voltage generated by armature = 600 + 25.4 = 625.4 V
Power generated = 625.4 × 508 = 317,700 W = 317.7 kW