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Publication numberUS3542942 A
Publication typeGrant
Publication dateNov 24, 1970
Filing dateSep 25, 1969
Priority dateSep 25, 1969
Also published asCA920674A, CA920674A1, DE2047840A1, DE2047840B2
Publication numberUS 3542942 A, US 3542942A, US-A-3542942, US3542942 A, US3542942A
InventorsHervig Harold G, Johnson Leonard A
Original AssigneeMinnesota Mining & Mfg
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
High voltage cable termination
US 3542942 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Nov. 24, 1970 A. JOHNSON ET AL 3,542,942

HIGH VOLTAGE CABLE TERMINATION Filed Sept. 25, 1969 A a/WWO OHIVJO/l BY fig/P040 CHaeV/q' j I W i ATTQP/VZ-YJ United States Patent Office 3,542,942 Patented Nov. 24, 1970 US. Cl. 174-73 7 Claims ABSTRACT OF THE DISCLOSURE An effective outdoor terminal of simple and economical structure for high 'voltage electrical cables, consisting of an elongate porcelain tube with close-fitting conical semiconductive rubbery end caps encircled by conductive flashover bands, the whole being provided with a filling of an insulating grease.

This invention relates to terminators for high voltage electrical cable having a conductive sheath. The terminator combines a highly insulative and track-resistant elongate ceramic tube forming the body of the device with semiconductive elastic end caps for axially supporting the tube on the conductor. The device therefore combines high insulative qualities with ease of assembly and application, and with economy of construction.

In the drawing,

FIG. 1 is a view in elevation and largely in cross section of a preferred form of terminator as applied to a high voltage cable end,

FIG. 2 is a section taken at line 2-2 of FIG. 1,

FIG. 3 is a vertical section of the lower end cap of the device of FIG. 1 prior to installation, and

FIG. 4 is a section taken approximately at line 44 of FIG. 1 of a portion of a structure similar to that of FIG. 1 but including an alternative form of encircling band and support.

The terminator of FIG. 1 includes an insulative externally annularly corrugated and grooved elongate porcelain ceramic tube 11 serving as the body of the device. semiconductive rubbery cap 12 fits over the upper end of the body 11 and around the constricted neck portion 13, being held in place both by its natural resiliency and by an encircling metal retaining band 14, the latter serving also as a flashover band to prevent localized concentration within the semiconductive cap of any excessive voltages. The neck 13 is externally grooved to form a narrow annular groove 15, and the cap 12 is preferably correspondingly annularly internally ridged, the ridge 16 fitting within the groove 15. A similar groove and ridge construction is illustrated 'at the small end of the cap 12. Nordel conductive ethylene-propylene terpolymer is an effective material of construction for such caps.

The lower end of the body 11 similarly terminates in a doubly annularly grooved neck 17 over which is applied a conical semiconductive elastic cap 18 of Nordel conductive polymer held in place by a retaining ring 19. The inner surface 20 of the thickened lower portion of the cone 18 has a stress cone configuration and is grounded to the conductive sheath 21 of the cable 22 and preferably also through the ring 19 to an external ground 23 as shown.

The interior of the structure is preferably partially filled with a thixotropic insulating grease, in a quantity sufiicient substantially to fill all voids remaining after insertion of a cable end. Although such greases do not ordinarily flow under normal ambient and handling conditions, it is usually desirable to seal the ends of the terminator structure prior to installation, to prevent both loss of grease and entry of dirt or other contamination. Ordinarily removable plub seals may be used, but the incorporation within the cap members of puncturable diaphragm retaining elements offers a number of advantages and is preferred. The diaphragms retain the grease under all ordinary conditions during storage and handling prior to installation, but are easily punctured and displaced by insertion of the conductor elements. A residual portion of such a diaphragm is shown in FIGS. 1 and 2 as fragment 24.

The typical installation of FIG. 1 shows the cable 22 from which a terminal portion of insulation 33 has been removed to expose the conductor 25. Permanent contact with a terminally pierced connector element 26 is made through an intermediate compression or crimping sleeve 27, and the assembly is then pushed into and through the terminator 10 as shown. The end cap 18 fits tightly about and provides conductive contact with the sheath 21, and the cap 12 similarly fits tightly about the element 26. The grease contained within the assembly serves to fill most of the voids otherwise present and to assure water resistant connections at both ends. The conductor 25 and element 26 are firmly held at the axis of the tube 11 and of the entire structure.

FIG. 3 shows the structure of the lower cap 18 prior to assembly on the tube 11 and cable 21, and in particular illustrates the location of diaphragm 28. This item is inset slightly from the smaller extremity of the cap for convenience in inserting the conductor 26, but sufficiently away from the surface 20 of the stress cone area to avoid undesirable electrical effects at that area.

Where the band 19 is shown as a continuous band in FIGS. 1 and 2, and must therefore be driven over the cap 12, the band 19' encircling the cap 18 is illustrated in FIG. 4 to be in the form of an adjustable clamp member having outturned ends 29 secured together by means of a bolt 30. Additionally, the ring 19' is supported on a bracket member 31 which may be attached to a pole or other supporting structure, e.g., by screw 32.

What is claimed is as follows:

1. A high voltage cable terminator assembly comprising an insulative exteriorly annularly corrugated and glazed elongate ceramic tube having at each end a generally conical semiconductive rubbery cap having a larger end, encircling the end of said tube and being in turn encircled with a metal retaining band, and an open smaller end for fitting closely about a high voltage line component.

2. The assembly of claim 1 containing a quantity of thixotropic insulative grease.

3. The assembly of claim 2 including a grease-retaining diaphragm within each of said end caps.

4. The assembly of claim 1 wherein the one of said end caps which is to be placed over the cable-end has a stress cone configuration.

5. The assembly of claim 4 wherein the metal band encircling the cap having the stress cone configuration terminator.

' 6. The assembly of claim 4 in position on a terminal of a high voltage cable enclosed within a conductive 5 sheath, wherein the cap having the stress cone configuration is disposed over the cable sheath and the band encircling said cap is grounded.

7. The assembly of claim 6 wherein said band serves as a component of a supporting bracket.

References Cited UNITED STATES PATENTS 3,322,883 5/1967 Lusk 174-73 3,377,420 4/1968 Brown et al. 174-73 LARAMIE E. ASKIN, Primary Examiner US. 01. X.R.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3322883 *May 3, 1966May 30, 1967G & W Electric Speciality CoPrefilled cable termination system
US3377420 *Apr 16, 1965Apr 9, 1968Elastic Stop Nut CorpDevice for terminating outdoor electric cables
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3730970 *Oct 4, 1971May 1, 1973Minnesota Mining & MfgTerminal with grease retaining members
US3777050 *Dec 30, 1971Dec 4, 1973American Esna CorpShielding tape grounding device for high voltage cables
US3877775 *Aug 27, 1973Apr 15, 1975Atomic Energy CommissionCable connector
US3878313 *Oct 4, 1974Apr 15, 1975Minnesota Mining & MfgPre-assembled cable termination
US4327245 *Jun 13, 1980Apr 27, 1982Industrie Pirelli, S.P.A.Sealing end for direct current electric cables
US5567230 *Apr 5, 1995Oct 22, 1996Sinclair; Hugh J.Air filter for use with aircraft ventilation systems
USRE28837 *Aug 4, 1975Jun 1, 1976Amerace CorporationShielding tape grounding device for high voltage cables
CN106025996A *Jul 25, 2016Oct 12, 2016常州市拓源电缆成套有限公司Waterproof outdoor cable terminal for railways
CN106207939A *Jul 25, 2016Dec 7, 2016常州市拓源电缆成套有限公司27500V outdoor power cable terminal for railway
Classifications
U.S. Classification174/73.1, 174/140.00R, 174/77.00R, 174/80, 174/76, D13/133
International ClassificationH02G15/068, H02G15/02, H02G15/064
Cooperative ClassificationH02G15/068
European ClassificationH02G15/068