Operation of Synchronous Machines (Contd.) — Lesson 9

This lesson covers the fundamental aspects of synchronous machines, their construction, and operation. It delves into the balanced 3-phase winding of synchronous machines, the role of the stator and rotor, and the concept of field current. The lesson further explains the operation of a synchronous generator in isolation and as part of an infinite bus. It highlights the importance of maintaining the same voltage and frequency in the bus and the machine for successful synchronization. The lesson also discusses the process of connecting a synchronous machine to the bus using a synchronizing switch and the conditions required for successful synchronization. An example of a four-pole machine running at a speed slightly different from its synchronous speed to achieve synchronization is used to illustrate these concepts.

Video Highlights

00:25 - Explanation of stator and rotor in synchronous machines
03:41 - Operation of a synchronous generator in isolation
06:02 - Process of synchronizing a synchronous machine with the bus
15:01 - Conditions for successful synchronization
16:25 - Example of a four-pole machine achieving synchronization

Key Takeaways

- Synchronous machines have a balanced 3-phase winding and operate in the range of mega watts.
- The stator winding is similar to that of a three-phase induction motor, while the rotor has a winding through which DC current is passed, creating a magnetic field.
- Synchronous generators can operate in isolation or as part of an infinite bus. In the latter case, the terminal voltage of the machine must match the voltage in the bus.
- Synchronization of a synchronous machine with the bus involves adjusting the machine's speed to be very close to, but not exactly, its synchronous speed. This allows for the machine to be "pulled into synchronism" when the synchronizing switch is closed at the right moment.