Summary
An overview of how three-phase synchronous motors function, focusing on the roles of the stator and rotor in maintaining synchronous speed.
Principles of Three-Phase Synchronous Motor Operation
Highlights
Fundamental Operation
A three-phase synchronous motor operates by applying a three-phase supply to its stator windings to create a rotating magnetic field, while the rotor is supplied with direct current (d.c.) excitation.
Synchronous Speed Mechanics
Unlike induction motors, the rotor in a synchronous motor rotates at the same speed as the stator field. This is because the rotor field is generated externally and possesses a fixed polarity and strength, allowing it to become magnetically coupled to the stator's field and locked into synchronous movement.
Excitation Methods
The rotor's excitation current can be independently controlled to adjust magnetic strength. Common methods for providing this d.c. excitation include using d.c. shunt generators or brushless excitation systems.