Skewing of Rotor — Lesson 9

This lesson covers the concept of rotor skewing in electrical machines, its effects, and the equations for skewing factor. It delves into the reasons for skewing the rotor and how it helps minimize the effects of slot harmonics, cogging, crawling, synchronous cusp, and noise and vibrations. The lesson also explains how to select the number of rotor slots to minimize these effects and provides a detailed explanation of the skewing factor equation. It further illustrates the concept with an example of calculating skewing factors for all dominant lower order harmonics and first and second order slot harmonics.

Video Highlights

00:00 - Introduction
00:20 - Explanation of empirical formulas for rotor slots
01:12 - Discussion on the effects of skewing on rotor
3:57 - Explanation of the skewing factor equation
22:16 - Illustration of skewing with an example
32:27 - Summary of the lesson

Key Takeaways

- Rotor skewing in electrical machines is essential to minimize the effects of slot harmonics, cogging, crawling, synchronous cusp, and noise and vibrations.
- The number of rotor slots can be selected using empirical formulas to minimize these effects.
- The skewing factor equation is derived based on the stator distribution factor.
- The lesson provides a practical example of calculating skewing factors for all dominant lower order harmonics and first and second order slot harmonics.