Understanding Three Phase Transformer Connections-3 — Lesson 4

This lesson covers the fundamentals of three phase transformer connections. It begins with an explanation of how a three phase transformer can be constituted using three identical single phase transformers or as a single unit of three phase transformers. The lesson then delves into the external connection of these transformers to transform a balanced three phase voltage into another balanced three phase voltage in the secondary. The importance of understanding the dot markings or polarities of the transformers is emphasized. The lesson concludes with a discussion on the shift in the secondary voltage with respect to the primary voltage and the angle by which the voltages shift.

Video Highlights

01:32 - Discussion on the shift in the secondary voltage with respect to the primary voltage
04:45 - Explanation of how to make a valid star connection
11:33 - Discussion on the concept of artificial neutral of the secondary site
19:02 - Explanation of how magnetic circuits work in DC circuits
29:50 - Demonstration of how to represent the primary and secondary phase voltage with respect to neutral using the clock convention

Key Takeaways

• A three phase transformer can be constituted using three identical single phase transformers or as a single unit of three phase transformers.
• The transformers are connected externally to transform a balanced three phase voltage into another balanced three phase voltage in the secondary.
• There is a shift in the secondary voltage with respect to the primary voltage, and understanding the angle by which the voltages shift is important.