Separately Excited DC Motor
In a separately excited motor, as shown in Figure 4.8, the field supply is provided in a manner other than by an armature supply.
Since the field current is taken from a separate supply, field current is independent of the load.
The flux remains essentially constant and does not affect either the speed or the torque.
These types of motors are not used generally, as they require a separate field supply and also large variations in field current apart from the armature circuit.