GB1052052A - - Google Patents

Abstract

1,052,052. Encapsulating electrical units. CONSOLIDATED ELECTRODYNAMICS CORPORATION. May 28, 1963, No. 21214/63. Heading B5A. [Also in Division H1] An assembly of electrical components comprising one winding of a transformer is encapsulated into a sealed unit having a plurality of terminals accessible from the exterior thereof, and a passageway in the encapsulating compound extends through the said one winding to allow the threading of a selected number of turns of wire therethrough to form a second winding for the transformer, said second winding being connected to at least two of said terminals. The description is similar to that of Specification 1,052,054. In Fig. 16 (not shown), two toroidal transformer cores 76 (one only visible), each carrying a first transformer winding, are partially embedded, together with a plurality of knurled terminals 43 and two fineadjusting potentiometers (not shown), in a front panel 64 in a first casting step. A printed circuit board assembly 92, comprising a plurality of components such as resistors, capacitors, transistors &c., and further terminals 43, is mounted on the front panel and wired thereto as required, the whole assembly then being placed in a mould 95, and covered with a plate 101 which is bolted to adjacent terminals 43. In order to provide a passageway through the transformer cores 76, pins 103 on the body of the mould 95 extend inwardly through the cores and are contacted by removable casting bars 105 introduced through rectangular apertures in front panel 64. Encapsulating compound is then poured into the casting cavity 106 of the mould, to produce an encapsulated assembly 23, Fig. 19 (not shown), having a passageway 110 through each transformer core to permit the number of turns of secondary windings 112 of the transformers to be adjusted as required. The ends of windings 112 are connected to terminals 43, which present flush surfaces with threaded holes at the surfaces of the encapsulated assembly 23. Assembly 23 is mounted with two further assemblies 24, 25, Fig. 1 (not shown), between a pair of angleshaped frame members 21, 22, the assemblies being electrically interconnected by a flexible printed wiring panel 30, which comprises conductors between two insulating sheets, enlarged, apertured contact portions of the conductors being in register with terminals 43 of the assemblies and connected thereto by contact screws 35, Figs. 20, 23, 24 (not shown), depict alternative contact arrangements. A single-step casting operation for encapsulating an assembly not comprising a transformer is also described in the Specification. Polyester resin containing a mineral filler such as ground silica powder, and a hardening agent, is mentioned as a suitable encapsulating compound.