GB936380A - Improvements relating to electrical coils - Google Patents

Abstract

936,380. Transformers and inductors. LICENTIA PATENT - VERWALTUNGS - G.m.b.H. July 13, 1962 [July 25, 1961], No. 26981/62. Class 38 (2). An electric coil comprises a plurality of coaxial windings cast in a mass of resin, the surfaces of the individual windings having spacing members which are penetrated by the resin and which serve to bound in part cooling channels which extend longitudinally between the windings. The spacing member may consist of a wrapping of wide mesh material. The surfaces of the windings are covered with spacing members, the windings assembled in position and core members inserted between the windings in contact with the spacing members so that after encapsulation the core members may be withdrawn to leave cooling channels. The core members may be rigid cylindrical rods which are removed before the resin is fully set or may have a sleeve of elastic material which undergoes a reduction in crosssectional area when a longitudinal force is exerted on it so that the cores may be removed after the resin has set. Alternatively, the core members may be entirely of elastic material or may be of a material which can be melted out after the resin is hard. Fig. 1 shows two sets of cylindrical windings 1, 2 magnetically connected by core 3 and having cooling channels 4 and terminals 6 cast in the resin. Core clamping members (Figs. 3a, 3b, not shown) may be held together in the direction of the coil axis by bolts which are embedded in the resin.