A short-shunt dc compound generator supplies 50 A at 300 V. If the shunt field resistance, series field resistance and armature resistance are 30 Ω, 0.03Ω, and 0.05 Ω respectively, determine the e.m.f. generated.

• A. 302.5 V
• B. 308.5 V
• C. 304.5 V
• D. 306.5 V

Answer: (C)

Here,
Vt = 300 V
Rse = 0.03 Ω, Rsh = 30 Ω, Ra = 0.05 Ω
I_L = 50 A

Vsh = V + I_L*Rse = 300 + 50*0.03 = 301.5 V
Ish = Vsh/Rsh = 301.5/30 = 10.05 A

Ia = Ish + I_L = 60.05 A

Eg = Vt + I_L*Rse + IaRa
Eg = 300 + 50*0.03 + 60.05*0.05 = 304.5025 V