Armature Reaction and Synchronous Reactance — Lesson 1

This lesson covers the analysis of electrical machines, focusing on the synchronous machine. It explains the equivalent circuit of a synchronous machine, the impact of field current on induced voltage, and the role of armature current when the machine is loaded. The lesson also discusses the concept of terminal voltage and the difference between power factor angle and the angle by which armature current lags the field. It introduces the concept of resultant field and explains how it affects the induced voltage in the coils. The lesson further elaborates on the equivalent circuit of a synchronous machine, the concept of synchronous reactance, and the difference between cylindrical and salient pole synchronous machines. It concludes with a discussion on the phasor diagram of a synchronous machine.

Video Highlights

00:15 - Introduction to electrical machines and synchronous machine analysis
03:38 - Explanation of the equivalent circuit of a synchronous machine
08:32 - Introduction to the concept of synchronous reactance
13:57 - Difference between cylindrical and salient pole synchronous machines
25:08 - Discussion on the phasor diagram of a synchronous machine

Key Takeaways

- The equivalent circuit of a synchronous machine consists of the field current, induced voltage, armature current, and terminal voltage.
- The armature current plays a significant role when the machine is loaded, affecting the resultant field and induced voltage in the coils.
- The synchronous reactance, which is the sum of the armature reaction reactance and leakage reactance, is a crucial parameter in the analysis of synchronous machines.
- There are two types of synchronous machines: cylindrical and salient pole. The main difference between them is the uniformity of the air gap.
- The phasor diagram of a synchronous machine is a useful tool for understanding the relationships between different parameters in the machine.