D.C. reactor

TLDR: A D.C. nuclear core as mentioned in this paper consists of two opposed cores separated by a magnetic gap, and each permanent magnet is shaped into a rectangle and disposed on both side surfaces of the center leg of the E-shaped core.

Abstract: A D.C. reactor comprising a core structure having two opposed cores separated by a magnetic gap, to form a closed magnetic circuit; a coil wound on one or both of the cores; a pair of permanent magnets for biasing, disposed on the core structure; magnetic flux generation means for causing the bias flux generated by the permanent magnets and the flux generated by the coils to flow in opposite directions; and bypass means for causing the bias flux generated by the permanent magnets to bypass the magnetic gap. The core structure comprises an E-shaped core and an I-shaped core, the magnetic gap is defined between a center leg of the E-shaped core and the I-shaped core, the coil is wound on the center leg of the E-shaped core, and each permanent magnet is shaped into a rectangle and disposed on both side surfaces of the center leg of the E-shaped core. The permanent magnet is a sheet-like permanent magnet magnetized so that each of its longitudinal direction and the direction of thickness forms two poles on each side, and the neutral line of this permanent magnet is brought into conformity with the center line of the magnetic gap and is disposed on both outer side surfaces of the core structure. Since the flux generated by the D.C. reactor does not pass inside the permanent magnet, an eddy current loss decreases, and even when a large current abruptly flows through the coil, the permanent magnet is not demagnetized.