GB621721A - Improvements in and relating to electric induction apparatus - Google Patents

Abstract

621,721. Transformers. BRITISH THOMSON-HOUSTON CO., Ltd. April 25, 1947, No. 11146. Convention date, April 27, 1946. [Class 38 (ii)] A transformer or other induction apparatus comprises a core with a leg which carries a winding on a spool, a multiple strip conductor winding with stepped ends interfitting with complementary surfaces on terminal members, and a terminal board including a pivoted link for short-circuiting the winding on the spool, and a reversible cover enclosing the terminal board. The taped primary winding 2 comprises two S-bent strips 5, 6 with ends of unequal lengths forming stepped surfaces brazed to complementary stepped surfaces on terminals 7, 8. The middle of the S passes through the window of a rectangular core which is made from two U-shaped members consisting of flatwise-bent magnetic laminations, as described in Specification 621,679. Secondary windings 3, 4 are wound on spools 10, each consisting of two, similar, overlapping channel-shaped pieces of pressboard, which allow fitting to cores of different cross-sections. Insulation between windings and core is completed by flanges 12 and extensions 13 on the spools, and insulation 23 round the core yoke holding insulation in place under the yoke. The core is held in place by a binding strip 27 which extends round the core and is welded at each end 29 to a bracket 26, in which the bottom core yoke is located. Two compensating windings pass through a hole 16 in the core, one being a single shortcircuited turn 19 and the other a multi-turn winding 17 connected between the two secondary coils 3, 4. An insulating cover comprising two concave parts 31, 32 and a central band 35 is bolted to bracket 26 and held together at its upper end by conducting strips which connect the ends of the secondary windings with terminals in a chamber enclosed by a cover 42 which must be placed in one of two positions according as to whether or not the terminals are short-circuited by a swivelling link inside the chamber. The casing may be compound. filled.