Understanding Eddy Current and Hysteresis Loss — Lesson 5

This lesson covers the concept of eddy current and hysteresis loss in transformers. It explains why using a solid block of iron in transformers can lead to increased eddy current loss and suggests using thinner plates to reduce this loss. The lesson also provides an approximate expression for eddy loss in a thin plate and discusses the factors on which eddy current loss depends. It further introduces the concept of hysteresis loss, which occurs due to the constant movement of molecules in the transformer core. The lesson concludes by suggesting ways to reduce both types of losses.

Video Highlights

01:00 - Discussion on how to reduce eddy current loss by using thinner plates
11:57 - Explanation of how eddy current loss depends on the maximum value of the flux density, supply frequency, and thickness of the plate
31:39 - Introduction to the concept of hysteresis loss
37:20 - Discussion on how hysteresis loss leads to heating of the core, not just due to eddy current, but also due to the constant movement of the molecules
38:00 - Conclusion of the lecture and a preview of the next lecture's topic

Key Takeaways

• Eddy current loss in transformers can be reduced by using thinner plates instead of a solid block of iron.
• The eddy current loss depends on the maximum value of the flux density, supply frequency, and thickness of the plate.
• Hysteresis loss occurs due to the constant movement of molecules in the transformer core when the current is time-varying.
• Both eddy current and hysteresis losses can be reduced by using materials with higher resistivity and by not using too high a flux density.