Induction coils coaxial with an arbitrary number of cylindrical conductors

Abstract

The vector potential has been obtained for a coil coaxial with an arbitrary number of cylindrical conductors. The derivation is quite general and employs an iterative process that has been adapted to computer programs. After the vector potential has been obtained, it is used to calculate the mutual and self-impedance of multiple and single coils, the effect of defects in the conductors on the mutual and self-impedances, and the induction heating density in the conductors.

Electromagnetic methods for measuring material properties of cylindrical rods and array probes for rapid flaw inspection

“…Figure 2.4 can be used to discriminate the outer layer depth by fitting frequency scan experimental data with the theoretical predictions. For coils encircling a long layered rod, the model in [43] has been applied in Appendix A and reference [33]to evaluate case depth of case hardened steel rods. However, in order to take measurements on short steel rods, end effects should be considered.…”

“…The work is partly stimulated by the need to evaluate case depths of a case hardened rods taking into account end effects. This avoids systematic errors that can arise whenever the data is interpreted using the infinite rod theory [42,43]. There are, in fact, many other possible applications of the finite rod analysis since the results provide, for example, a simple method of calculating the impedance of a lossy inductor with a cylindrical core.…”

“…Deeds [43] generalized the solution for a coil coaxial with a cylindrical conductor having an arbitrary number of concentric, homogeneous layers. The vector potential, also expressed in the form of Bessel integrals, employs an recursive relationship to link solutions in adjacent layers [43].…”

“…The vector potential, also expressed in the form of Bessel integrals, employs an recursive relationship to link solutions in adjacent layers [43].…”

Simulation of Cracks Detection in Tubes by Eddy Current Testing

“…Early, Dodd's works present the known general model for axisymmetric problems [11]. The conductor can have any number of layers and the studied geometries fall into two major categories: planar and coaxial cylindrical layers.…”