GB1166835A - Improvements in or relating to Electromagnetic Inductors - Google Patents

Abstract

1,166,835. Reactors. GENERAL ELECTRIC & ENGLISH ELECTRIC COMPANIES. 1 Sept., 1967 [26 July, 1966], No. 33492/66. Heading HIT. An electromagnetic inductor comprising an inner core limb of ferromagnetic material carrying one or more electrical windings, and an outer core shell of ferromagnetic material which extends across the end faces of the inner core limb to enclose the inner core limb and the winding, has an inner core limb which projects at each end beyond the winding, at least one projecting end being associated with magneticflux-diverting means the effect of which is, in use of the inductor, to divert some of the flux in the inner core limb away from the part of the shell opposite each end face of the inner core limb to other parts of the outer core shell removed from said part. The flux-diverting means may be constituted by bending back some of the surface laminations of the inner core limb in the region of the projecting ends (Fig. 3, not shown), or by bending up the ends of such surface laminations (Fig. 4, not shown), or by the use of L-shaped laminations for the inner core-limb (Fig. 5, not shown), or by the use of l-shaped laminations for the inner core limb (Fig. 6, not shown), or by the use of laminated or solid insert pieces (Figs. 1, 7, 8, 29, not shown), or by cranking corner regions of the outer core shell members (Figs. 10, 11 and 12, not shown). Several ways in which various embodiments may be combined are described. The inner core limb may be comprised of one or more stacks of laminations separated by air gaps filled with insulating blocks or adhesive, and the outer core shell may comprise two L-shaped laminated members or a U-shaped laminated member interfitted in each case with a U- shaped laminated member. The completed inductor, which may be used as a ballast choke in discharge lamp circuits, is encased and dipped in varnish.