GB940148A - Improvements relating to electric cable terminations - Google Patents

Abstract

940,148. Cable terminations. ASSOCIATED ELECTRICAL INDUSTRIES Ltd. April 3, 1962 [April 14, 1961], No. 13628/61. Heading H2E. A hollow conductive terminating structure, for use with a fluid-cooled cable comprising a hollow permeable conductor 1 with a central duct 2 surrounded by a coolant retaining layer 3, is adapted to be secured over and electrically connected to the bared end of the cable conductor 1, and has a part for sealing impermeably to said layer 3, at least one coolant port and communicating with the latter, insulated coolant ducting of length such as to allow only a permissible leakage current. Fig. 1 shows an embodiment in which the layer 3, of fairly resilient material such as butyl rubber, is clamped between a clamping ring 9 and a complementary wedge-shaped ring 8 secured to a hollow sleeve 6, thus connecting the central duct 2 via the sleeve 6 to a port 11 in the sleeve 6 and hence to external insulated ducting (not shown). The sleeve 6 is compressed on to the reinforced end of conductor 1 to connect the latter to a termination 12. An earthed supporting member 13, bonded to the metal cable screen 4 at 14, is insulated from sleeve 6 by an intermediate tube 16 of solid insulation or of wound laminated structure. In the embodiments of Fig. 3 and Fig. 2 (not shown), where the coolant ducting is built into the terminating structure, ports 22 in sleeve 6 open into an annular chamber 23 which communicates through a sealing flange ring 25 with ducts 29 in a second insulator 26 surrounding the tube 16. The duct 29 in turn leads to a port 30 in a support flange 13 and hence to a coolant supply, the length of insulator 26 being determined by the leakage current requirements. Whereas the embodiment of Fig. 2 has a similar form of sealing clamp to that shown in Fig. 1, Fig. 3 shows a different arrangement, suitable for a coolant retaining layer of thermoplastic material such as polythene, wherein either the end portion 33 of the layer 3 fits over the ridged tubular part of a flanged member 31 and forms a seal, or as shown, a sleeve 34 of the same material as the layer 3 is moulded over the end of the layer and the member 31.