High Frequency Apparatus Page 156

156 HIGH FREQUENCY APPARATUS Core requires 80 pieces 116 260 pieces 26. 340 pieces 8*7" silicon steel.on" thick. Tooden block. Fig. 1 T Fig.5 Fig.6 Fig. 4 72 One leg assembled and foped ready for winding Leg with primary winding in place Fibre shield Fig. 2 Cover with layers olled paper wide Taped Ends forced info block. One side of winding completed Core reversed in latba Insulation Fig. 9 Fig. 7 Fig. 8 Fig 3 3loyers press board Shiela Sechon through coil Location of fibre shield and core from reel Section A A Figs. 1 to 8 inclusive.-Details of the magnetic leakage transformer clamping the core leg in the lathe for winding. Before starting the winding, a strip of thin copper ribbon is cemented to the insulation as shown in Fig. 7 to provide the connection between the two halves of the secondary. A strip of paper is placed over the ribbon and the winding started after the end of the wire has been soldered to the ribbon. When the first section of the secondary has been completed, the finishing end of the wire is soldered to a piece of ribbon, a few turns of paper taken over the final layer of wire, and the core leg removed from the lathe. The fibre shield which separates the two secondary sections is then slipped in place and the core replaced in the reverse direction; that is, the core is turned end-for-end in replacing it to make the blank portion of the core take the place of the wound section. The second half of the winding is then started by soldering the wire to the copper strip as before. Assuming that the lathe is turned always in the same direction, the act of reversing the core insures that the direction of the winding shall be continuous in both sections, with their starting ends connected together by means of the copper strip.