Basically in a field controlled dc motor, the armature current is kept constant (via some constant voltage source) while the field current is varied which will vary the field flux and interacts with the armature of motor and produce rotation. But why does the armature current not change when flux interaction is there with the armature and voltages are flowing around the motor. How does the armature current remain constant. Does the speed of rotor changes to bring the armature current back to the constant value?? What causes the armature current to not change from its constant value?