Self and Mutual Inductances of Coupled Coils — Lesson 2

This lesson covers the principles and operations of three-phase induction motors, single-phase induction motors, and synchronous motors. It begins with a discussion on the basic principles of rotating machines, highlighting the common underlying principles that govern the operations of all standard electrical motors. The lesson then delves into the steady-state performance analysis of these machines. It also discusses the concept of equivalent circuits and how they are used to predict the performance of a particular machine. The lesson assumes prior knowledge of transformers and DC machines. It also touches on the concept of windings on electrical machines and the basic principles of any rotating machines.

Video Highlights

00:20 - Introduction to self and mutual inductances of coupled coils
02:30 - Discussion on time varying current and induced voltage
03:50 - Explanation of Faraday's law
16:38 - Discussion on equivalent circuit of a transformer
19:11 - Explanation of KVL equation of primary and secondary side

Key Takeaways

- The mutual inductance between two coils can be depicted using the dot convention, which shows the instantaneous polarities of the primary and secondary side voltage.
- A time varying current can induce voltage across the secondary terminals. This is based on Faraday's law which states that the polarity of the induced voltage in any coil should be such that it will try to oppose the very cause for which it is due.
- The KVL equation of the primary and secondary side can be written and simplified to get an equivalent circuit of a transformer.