Understanding Electrical Machines: Auto Transformers — Lesson 6

This lesson covers the concept of auto transformers in electrical machines. It delves into the workings of a two-winding transformer and how it can be connected as an auto transformer. The lesson explains how to calculate the distribution of current in several windings and the interesting features of a two-winding transformer. It also discusses the practical applications of auto transformers, such as starting a three-phase induction motor and connecting two power systems. The lesson further explains the concept of a practical auto transformer and how to analyze a circuit involving a non-ideal auto transformer. For instance, if you want to connect two power systems with slightly different voltage levels, an auto transformer can be used to balance the voltage and allow the systems to work in parallel.

Video Highlights

00:15 - Introduction to auto transformers
04:04 - Practical applications of auto transformers
15:08 - Analyzing a circuit involving a non-ideal auto transformer
34:03 - Drawing the equivalent circuit of an auto transformer

Key Takeaways

• An auto transformer can be used to balance the voltage between two power systems and allow them to work in parallel.
• The voltage ratios in an auto transformer are close to 1, which makes it a cost-effective solution for connecting power systems with slightly different voltage levels.
• A practical auto transformer has resistance and leakage reactance, which need to be considered when analyzing a circuit involving an auto transformer.
• The equivalent circuit of an auto transformer can be drawn by referring to the source side and considering the resistance and leakage reactance.