Eddy currents and electrical surface charges

✍ Scribed by Eckhard Baum; Otto Erb

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 436 KB
• Volume: 16
• Category: Article
• ISSN: 0894-3370
• DOI: 10.1002/jnm.489

✦ Synopsis

Abstract

In eddy current calculations, the displacement current in the non‐conducting space surrounding the eddy current region is usually neglected. This assumption enforces that the electric charge density and the accompanying normal components of the eddy current density on the surface of the eddy current region must vanish.

If the field exiting source currents are not accompanied by charges this assumption may yield acceptable results for the eddy current distribution. However, if the field exiting source currents are accompanied by charges, this assumption may lead to totally wrong results for the current distribution in the eddy current region. An example is given which makes plain this point.

To obtain correct results it is not necessary to employ the full set of Maxwell's equations capable to describe wave propagation phenomena also outside the eddy current region. It is shown in the paper that by replacing the displacement current density in the field describing equations by a specifically chosen current density function makes it possible to determine eddy currents and surface charges within the quasi‐stationary calculation scheme for arbitrary field exciting source currents which may or may not be accompanied by charges. The solution obtained in this way is shown to be unique. Copyright © 2003 John Wiley & Sons, Ltd.