Learning Forum

[lee.seungwoo]

Hello,

I am a user of Ansys Maxwell 3D, utilizing the Eddy Current mode to study microcoils. I am writing to inquire about the analysis method used in the Eddy Current mode.

In the Eddy Current mode, there is a checkbox for enabling or disabling the "Set Eddy Effect." I am curious about how turning this option on or off affects the analysis.

From my understanding, enabling the Eddy Effect incorporates both the 3rd and 4th Maxwell equations, specifically including the Ampère-Maxwell law, in the analysis. On the other hand, disabling it limits the analysis to only the 3rd equation, which is Faraday's law. Is my understanding correct?

I would greatly appreciate your response.

Thank you.

[Timos]

Hello, when you enable the "Set Eddy Effect" option, the solver computes the induced eddy currents within the conductors in your model. This is indeed related to the incorporation of the Maxwell equations, including the Ampère-Maxwell law, which is the 4th Maxwell equation. It describes how a magnetic field is generated by an electric current and a changing electric field. Conversely, when you disable this option, the analysis does not account for the eddy currents that would be induced by the changing magnetic fields, which is a simplification of the problem that might be valid under certain conditions where the eddy current effects are negligible.

For a more detailed understanding of how this setting affects your analysis, you can refer to the Ansys Maxwell documentation titled "Setting Eddy Effects and Displacement Current" which provides insights into the behavior of eddy currents and the AC magnetic field in conductors when the Eddy Effect setting is activated. https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/Electronics/v232/en/home.htm%23../Subsystems/Maxwell/Content/SettingEddyEffectsandDisplacementCurrent.htm?TocPath=Maxwell%257CMaxwell%2520Help%257CAssigning%2520Boundaries%2520and%2520Excitations%2520for%25203D%2520Designs%257C_____6

[lee.seungwoo]

Thank you so much for your kind response.  

One thing I want to clarify is that even when the "eddy effect" checkbox is unchecked, the J, E, and B fields still appear. I believe these are the magnetic field (B0) generated by the current flowing inside the insulated coil, and the magnetic field (B1) generated to counteract B0, for which the electric field (E1) and induced current (J1) are generated. In other words, if considering the eddy effect means that E1 generates another magnetic field (B2), and this process is repeated infinitely (3rd & 4th Maxwell equation), then turning off the eddy effect would mean that only the magnetic field (B1), electric field (E1), and current (J1) resulting from the current in the coil are output, and all subsequent effects are ignored (only the 3rd Maxwell equation).  

Would this interpretation be correct?  

The link you provided seems like it will be very helpful for solving other problems as well. Once again, thank you so much for your kind response.