Stator Winding Design for Variable Pole Machines — Lesson 6

This lesson covers the concept of stator winding design for variable pole machines. It explains how to change the number of poles and phases without altering the stator winding connections by using pole phase modulation techniques for induction machines. The lesson provides a detailed explanation of the process using an example of an 18 slot 3 phase 2 pole winding. It also discusses the concept of pole pitch, coil pitch, and the formation of flux loops. The lesson further explains how to change the number of poles from 2 to 4 or 6, and the drawbacks of conventional pole changing techniques. It concludes by discussing the advantages of multi-phase machines and the generalization of pole phase modulation.

Video Highlights

00:00 - Introduction
00:24 - 18 slot, 3 phase, 2 pole winding example
05:29 - Process of changing the number of poles
11:18 - Drawbacks of conventional pole changing techniques
12:26 - Achieving the symmetrical pole formation without changing stator terminals
24:33 - Generalization of pole phase modulation

Key Takeaways

- The number of poles and phases in a variable pole machine can be changed without altering the stator winding connections using pole phase modulation techniques.
- The process involves understanding concepts like pole pitch, coil pitch, and the formation of flux loops.
- Changing the number of poles from 2 to 4 or 6 involves altering mechanical connections and excitations.
- Conventional pole changing techniques have drawbacks like the requirement of a higher number of terminals and customized winding design.
- Multi-phase machines offer advantages like lesser space harmonics, higher efficiency, better power distribution, and improved fault-tolerant capability.
- The pole phase modulation equation is a key tool in changing from one pole combination to another.