Inductances of Distributed Winding - I — Lesson 1

This lesson covers the concept of inductance in electrical machines, focusing on machines with a cylindrical rotor, cylindrical stator, and salient pole rotor. It explains the challenges in determining the self-inductance of a single coil on the stator due to complex air variations and changing flux density waveforms. The lesson introduces the two-reaction theory proposed by Blondel to address these issues. It also discusses the concept of phase spread and the impact of a distributed stator winding on inductance. The lesson concludes with an explanation of how to determine the MMF variation of a uniformly distributed stator phase winding.

Video Highlights

00:11 - Introduction
05:01 - Discussion on the concept of MMF components and their role in determining the flux density
08:44 - Detailed mathematical derivation of the expression for the flux linkage and the inductance using the two reaction theory
15:37 - Comparison of the derived inductance expression with the actual variation of inductance in a cylindrical stator with a salient rotor
19:14 - Process of determining the inductances in single coil on the stator and rotor machine and cylindrical stator and salient pole rotor machine
27:08 - Explanation of 4 pole salient rotor structure with 3D animation
34:22 - Introduction to the concept of distributed stator winding in machines and how it affects the determination of inductance
46:50 - Overview of how the MMF waveforms are determined for a uniformly distributed stator phase winding using the ampere law

Key Takeaways

- The self-inductance of a single coil on the stator is difficult to determine due to complex air variations and changing flux density waveforms.
- The two-reaction theory proposed by Blondel helps solve this issue by converting the problem into a constant air gap case.
- In actual machines, the stator winding is distributed over a certain angle, known as the phase spread.
- The MMF variation of a uniformly distributed stator phase winding can be determined using Ampere's law.