Introduction
A synchronous motor is an AC motor in which the rotor rotates at the same speed as the rotating magnetic field of the stator. It is widely used in applications requiring constant speed.
Main Components
Stator:
- Stationary part containing three-phase windings.
- Produces a rotating magnetic field when AC supply is applied.
Rotor:
- Rotating part of the motor.
- Can be made of salient poles or cylindrical poles.
- Requires external DC supply for excitation.
Exciter:
- Provides DC supply to the rotor winding.
Shaft:
- Transfers mechanical energy to the connected load.
Bearings:
- Supports the rotor and ensures smooth rotation.
Frame:
- Protects and encloses the motor components.
Working Principle
- When three-phase AC voltage is applied to the stator, a rotating magnetic field is produced.
- The rotor is supplied with DC current, creating a fixed magnetic field.
- The rotor locks into the rotating magnetic field of the stator and rotates at the same speed (synchronous speed).
- The motor maintains constant speed regardless of load variations.
Types of Synchronous Motors
- Salient Pole Motor: Used in low-speed applications like hydroelectric generators.
- Cylindrical Rotor Motor: Used in high-speed applications like gas turbines.
Applications
- Power generation
- Pumps
- Compressors
- Industrial drives
- Clocks
Conclusion
Synchronous motors are known for their constant speed operation, efficiency, and precision. They are essential in applications where speed accuracy and stability are required.