How are synchronous motors typically started?

Synchronous motors are typically started using the amortisseur winding, which is also known as the auxiliary or damper winding. This winding is usually embedded in the rotor and consists of conductors that are short-circuited at the ends. When the synchronous motor is powered up, this amortisseur winding helps the rotor to experience a torque that aligns it with the magnetic field produced by the stator.

Initially, as the motor accelerates, the amortisseur winding allows the rotor to "slip" through the magnetic field, providing the necessary torque to bring the rotor up to near synchronous speed. Once the rotor reaches that speed, the synchronous motor can then lock into synchronism with the magnetic field, achieving stable operation. This method of starting is particularly important since synchronous motors do not have inherent self-starting capabilities.

Using other methods for starting a synchronous motor might not provide the required starting torque or could lead to operational issues. For instance, using an external power supply or direct line voltage can create difficulties because synchronous motors require the rotor to be at synchronous speed to take advantage of the magnetic field effectively. A resistive starter may not be suitable for synchronous motors due to their unique operational characteristics. In summary, the utilization of the amortisseur winding is