Realization of DC Machine — Lesson 1

This lesson covers the study of magnetic circuits with single and multiple excitations, as well as circuits with permanent magnets and electromagnets. The lesson further explains how these principles are applied in the design and operation of electrical machines, such as motors. It also discusses the challenges of demagnetization and magnetization of permanent magnets, and how to overcome them. The lesson concludes with a discussion on how to avoid the use of brushes and commutators in DC machines.

Video Highlights

00:00 - Introduction and summary of magnetic circuits
00:30 - Discussion on magnetic circuits with single and multiple excitations
01:44 - Application of these principles in electrical machines
07:36 - Demagnetization and magnetization challenges of permanent magnets
13:53 - Strategies to overcome these challenges
20:32 - How to avoid magnetic locking?
24:15 - How to change the current at 90 degree intervals?
25:18 - Brushes and commutators allignment
27:48 - How to get the uniform torque
39:18 - Discussion on challenges

Key Takeaways

- There are different types of magnetic circuits, including those with single and multiple excitations, and those with permanent magnets and electromagnets.
- The demagnetization and magnetization of permanent magnets present significant challenges in the operation of electrical machines.
- These challenges can be overcome by changing the excitation at the stator side or by adding multiple windings at the rotor side.
- Brushes and commutators, traditionally used in DC machines, can be avoided through certain strategies.