Patent GB-397312-A (GB)
Title: Improvements in or relating to electric transformers
IPC: H01F27/32
Filed: 1932-09-15
Abstract: 397,312. Transformers. WESTING- HOUSE ELECTRIC & MANUFACTURING CO., East Pittsburg, U.S.A.-(Assignees of Putman, H. van de V. ; 169, Buhl Boulevard, Sharon, Pennsylvania, U.S.A.) Sept. 15, 1932, No. 25671. Convention date, Oct. 6, 1931. [Class 38 (ii).] A high-voltage transformer winding comprising a number of coil structures connected together is insulated by a series of nested barriers, each larger barrier of the series enclosing the smaller barriers and at least one coil structure not included within a smaller barrier. In one arrangement, Fig. 9, for a winding earthed at one end, the high-voltage winding comprises a series of coils 43-49, which are graded in size to provide increased spacing from the core as the high voltage end of the winding is approached. A static plate 40 and the coil 43 comprising the high voltage end of the winding are connected to the line 51 and surrounded by an insulating barrier 53. Succeeding barriers 54 .. 59 are provided, each of which surrounds one of the coils 44 . 49, together with the smaller coils of the coil stack and the associated barriers. With this arrangement, the insulating barriers follow, approximately, the equipotential surfaces. The low voltage windings 41, 42 of the transformer are placed adjacent the end of the core. In a modification, Fig. 13, which shows one window of a shell-type core, the high-voltage winding is arranged in two series of graded coils connected in parallel between the line 86 and ground conductor 87, the successive coils of the two groups extending from the centre of the winding to points adjacent the low-voltage windings 79, 81. A series of nested insulating barriers 98 .. 104 is provided, the inner barrier 98 surrounding the high voltage terminal coils of each group and the static plate 88, while each succeeding barrier surrounds these coils together with the next larger coils of the two groups. In the arrangement, shown in Fig. 14, the low-voltage winding is divided into three sections 106, 107, 108 connected in series, and the high-voltage winding is divided into four groups of graded coils 115 .. 118, the groups being arranged in pairs with insulating barriers similar to those shown in Fig. 13. A similar duplication of the arrangement of Fig. 9 is described, Fig. 15 (not shown). In the arrangement shown in Figs. 17 and 18, the first three coils 145, 146, 147 of the high-voltage winding are connected with the inner end of one coil to the outer end of the next, but the remaining coils 148 .. 151 are connected at adjacent ends. The first three insulating barriers 159, 160, 161 surround the static plate 144 and the first two coils 145, 146 and are nested in the manner already described, but the remaining barriers 162, 163 extend at one end between an adjacent pair of coils, then about one end of the coil stack, and then between a coil of said pair and an adjacent coil, as shown in Fig. 18. In another arrangement, Fig. 19 (not shown), each insulating barrier surrounds two coils not enclosed in the next smaller barrier. If neither end of the winding is to be earthed, the arrangement, shown in Fig. 20, may be used, where the coils are arranged in two groups 168.. 171 and 172 .. 175, each provided with a nested series of insulating barriers, with additional barriers surrounding both groups of windings. The Specification as open to inspection under Sect. 91 comprises also arrangements for coil type transformers in which the insulating barriers are discontinued along the outside of the column of coils, so that they do not completely enclose the coils. In one arrangement, Fig. 21 (Cancelled), the low-voltage winding 188 is placed adjacent the core 187 and the high-voltage winding comprises a stack of coils 189 connected to the high-voltage conductor 190 at one end and earthed at the other end 191. Insulating barriers 192 .. 196 extend between the column and the core, each barrier being turned outwardly between adjacent coils at spaced interval along the column. Additional disc-shaped barriers 197 and barriers 198 of L-section are employed as shown. Fig. 22 (Cancelled) shows a similar arrangement applied to a high-voltage winding comprising a stack of coils 189 earthed at both ends 202, 203, the high-voltage conductor 201 being led in the centre of the stack. This subject-matter does not appear in the Specification as accepted.