ELECTROMAGNETIC COIL AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a method by which the insulation between strand conductors and element wires constituting the strand conductors can be secured in an electromagnetic coil which is used in an environment, in which the coil is exposed to radiation and constituted by winding the strand conductors. SOLUTION: A polyimide resin having a superior radiation resistance is impregnated into the gaps between the strand conductors and cured. In order to prevent the polyimide resin from flowing out immediately after the impregnation and in the step of curing the resin, silica powder is mixed in the resin for adjusting the coefficient of viscosity of the resin. The mean particle diameter and mixing amount of the silica powder in the polyimide resin are respectively adjusted to <=1.5μm and 5-15 wt.% so that the powder may prevent the resin from flowing out and may not hinder the impregnation.