Answer to Question #333769 in Electrical Engineering for Precious

Question

Consider a dc machine whose circuit model is drawn below. It is a separately excited

machine as its field coil (winding) is excited from a voltage source independent of the

armature circuit. A 25 kW, 250 V dc machine is separately excited. The field current

is held constant at a speed of 3000 rpm. The open circuit voltage is 250 V. Calculate

the terminal power, electromagnetic power and torque at terminal voltage of 255 V

and 248 V. The armature resistance is 0.05 W. Speed is held constant at 3000 rpm.