GB932737A - Electrical apparatus incorporating a transistor switch - Google Patents

Abstract

932,737. Ignition coils. ELECTRIC AUTOLITE CO. July 14, 1959, No. 24188/59. Class 38 (2). [Also in Group XXVII] An ignition coil for an engine ignition system (see also Group XXVII) is described. It has been found very effective to make the core 43 of high permeability steel or of magnetic materials capable of carrying a very high magnetic flux per unit of cross-sectional area and that a core produced of grain oriented high percentage silicon steel serves the purpose very successfully. The core 43 is preferably formed of a multi-turn winding of a ribbon of grainoriented high silicon steel coated to separate and hold in position its turns an air gap 45 ranging from 0.005 to 0.30 inches serves its purpose very effectively, a thin plate 47 of non- magnetizable material is inserted in the gap. The primary winding has a relatively low inductance and utilizes comparatively few turns. The coil has a very high turn ratio between its primary and secondary windings. The coil is compared to conventional coils. In Fig. 2 the ignition coil comprises a core formed by two U-shaped sections facing each other and separated by air gaps 45<SP>1</SP>. Either the primary or the secondary may be in close proximity to the core and surrounded by the remaining winding. Details are given of the inductances and current carrying capacities of the primary windings and the number of turns of the windings are quoted.