Abstract
It was found that the magnetic circuit approach, which is useful in situations where magnetic flux is interrupted by air gaps, is also helpful in illustrating magnetic shielding. Equivalent magnetic circuits of single and multiple cylindrical shields were developed and analyzed. Simple and explicit equations describing the shielding factors in terms of the reluctances of the shielded area, the shells themselves, and the spaces between them were obtained. To simplify evaluation of corresponding reluctances, flux density is assumed to be distributed uniformly throughout the shield parts, including the shells and the spaces between them. The resulting equations exactly reproduce well-known approximate analytical formulas. An important advantage of the proposed method over numerical ones is that it allows a straightforward physical insight into the shielding problem.
