Q. A dc series motor has an armature resistance of 0.06 Ω and series field resistance of 0.08 Ω. The motor is connected to a 400 V supply. The line current is 20 A when the speed of the machine is 1100 rpm. When the line current is 50 A and the excitation is increased to 30%, the speed of the machine in rpm is
A. 1100 RPM
B. 1003 RPM
C. 837 RPM
D. 938 RPM
Answer: 837 RPM
