Here's why:
* Excitation refers to the process of creating a magnetic field in the rotor of the synchronous motor.
* Field current is the current that flows through the rotor windings to create this magnetic field.
Therefore, the field current is the current responsible for the excitation of the rotor magnetic field.
In simpler terms:
* Excitation current is the general term for the current needed to create the magnetic field in the rotor.
* Field current is the specific current that flows through the rotor windings to achieve this excitation.
While the terms are often used interchangeably, understanding their connection is crucial for grasping the working principle of synchronous motors.
