When operating from a 230 V dc supply, a DC series motor operates at 900 rounds per minute with a line current of 75 Amps. Its armature-circuit resistance is 0.13 Ohms, and its series-field resistance is 0.09 Ohms. Due to saturation effects, the flux at an armature current of 25A is 45 percent of that at an armature current of 75 Amps. Find the motor speed when the armature voltage is 230 V and the armature current is 25 A.
V = Ea + (Ra+Rf)*Ia
Ea = k*Phi*W
V = Terminal voltage; Ea = Armature Voltage;
Ra=0.13 Ohms, Rf = 0.09 Ohms; Ia ...
The solution is provided step-by-step equationally.