US1829032A

US1829032A - Outlet for high potential cables

Info

Publication number: US1829032A
Application number: US127273A
Authority: US
Inventors: Arthur O Austin
Original assignee: Ohio Brass Co
Current assignee: Ohio Brass Co
Priority date: 1926-08-05
Filing date: 1926-08-05
Publication date: 1931-10-27
Anticipated expiration: 1948-10-27

Description

Oct. 27, 1931. o, us 1,829,032

OUTLET FOR HIGH POTENTIAL CABLES Filed Aug. 5, 1926 4 Sheets-Sheet 1 B Y WMI/LQA X A TTORNEYS Oct. 27, 1931. A. o. AUSTIN OUTLET FOR HIGH POTENTIAL CABLES 4 Sheetse-Shet 2 Filed Aug. 5, 1926 f INVENTOR BY (2 1; 3

ATTORNEYS Oct. 27, 1931. A. o. AUSTIN OUTLET FOR HIGH POTENTIAL CABLES Filed Aug. 5, 1926 4 Sheets-$heet 3 lll INVENTOR BY A WWM i ATTORNEY J Oct. 27, 1931. A. o. AUSTIN 1,829,032

OUTLET FOR HIGH POTENTIAL CABLES 7 Filed Aug. 5', 1926 4 Sheets-Sheet 4 [Z 1 N V EN TOR.

By J

ATTORNEYS,

Patented Oct. 27, 1931 UNITED S TATESPA TENT OFFICE AItTHUR O. AUSTIN, OF BARBERTON, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO

THE OHIO BRASS COMPANY, OF MANSFIELD, OHIO, A CORPORATION OF NEW JERSEY OUTLET FOR HIGH POTENTIAL CABLES Application filed August 5, 1926. Serial No. 127,273.

This invention relates to a construction by means of which a conductor of a high potential cable is brought out from its insulating covering in position to be connected with an overhead support or with any form of apparatus.

The object of the invention is to provide a device which is easily installed, which effectively protects the cable at its termination and which provides for proper distribution of the electrostatic flux to avoid concentration of the flux and minimizes danger of discharge.

The invention is exemplified in the combination and arrangement of parts shown in the accompanying drawings and described in the following specification, and it is more particularly pointed out in the appended claims.

In the drawings Fig. 1 is a part elevation and part section of a cable terminal showing one embodiment of the present invention;

Fig. 2 is a view similar to Fig. 1 showing a modified form of the invention;

Fig. 3 is a view similar to Fig. 1 showing a different modification; and

Fig. 4 is a view similar to Fig. 1 showing still another modification.

Frequently the only trouble with high voltage cable installations is in connection with the potheads or terminal bushings for the insulated cables. As ordinarily made, the cables consist of a conductor covered with insulation over which is placed a lead sheath to keep out water and to keep in impregnation. The insulating material of the cable may be made of paper, varnished cambric, rubber or other suitable material. Vhere the insulation is made up with paper or varnished cambric impregnated with oil, it is necessary that moisture be kept from entering the cable sheath and it is also necessary that the impregnating oil or compound does not escape. In order to prevent this it is necessary to join the lead sheath to the terminal bushing by some means so that a tight joint will be maintained and the conductor passing through the cable effectively insulated from ground and from the sheath. In order to provide a better and cheaper terminal device and one which may be more readily installed without damage to the insulation of the cable, I have made up a new and improved type of cable terminal or pothead.

In the invention as illustrated in Fig. 1, the conductor 11 is covered by a layer of in sulation 12 which in turn is covered bv alead sheath 13. The pothead consists of an insulating element 14 having an exposed portion and a covered portion where the cable enters. The dielectric member 14 is provided with an insert 15. A passage 16 is provided in the insert or partially in the in sert and partially in the dielectric member. This permits the escape of air and the entry of compound or oil to fillup the space between the insulation 11 and the inner walls of the insulator 14.

Toinstall the cable the lead sheath is removed the required distance and a terminal bolt 17 sweated or compressed to the con-.

ductor 11. Either after or before the stripping of the excess lead. the belled piece 18 is slipped over the lead sheath 13. The end of the lead sheath is then flared outward as at 19. The terminal bolt 17 withcable attached is then drawn up through the bushing or insulator 14 so that the lead sheath 13 will come into contact with the lower end of the insulator as at 19. The member 18 is then drawn up against the lead sheath by a clamping element 20. This may be in the form of a ring in some cases, in sectors, or in any other convenient form. The outer surface covered by the bell 18 and clamping member 20 may be metallized or if the

members

18 and 20 are close together, this is not necessary.

This means of attachment makes it possible to avoid all parts attached to the lower end of the bushing and avoids the necessity of wiping joints, although, of course, a wiped joint may be used in place of the clamped one, as shown.

A gasket may be placed against the flared end of the lead sheath to take up any inequality or in most cases the lead will'deform and form a tight joint. After the cable is in place the space may be filled through the hollow core of the cable, allowing air to escape through the passage 16 or the space may be filled by pouring an insulating material through the opening 16 after which the terminal cap 21 may be secured into place, sealing the bushing by means of the gasket 22.

A slightly different form of the invention is shown in Fig. 2. In this case a continuous clamp 23 is used and a vent 24 running through the terminal bolt is used for connecting with the space between the cable and the upper end of the insulator.

Another modification is shown in Fig. 3. This form is particularly applicable for comparatively high voltage potheads used out of doors. A flange 25 is cemented or otherwise attached to the dielectric member 14. A clamping bell 26 is used to attach the lead sheath to the lower end of the insulating member, a gasket 27 being used between the lead sheath and the insulator. In some cases it may be advisable to use the gasket and cushion 27 on the outside of the lead sheath rather than on the inside. This makes it possible to maintain the lead in contact with the surface, providing it is possible to exert sufficient pressure on the gasket or cushion so that the lead will deform.

In this form of terminal, the space between the upper end of the cable and insulator is filled by removing one of the plugs 28. A bracket 29 may be used for attaching the pothead to cross-arm or other suitable support. It will be seen that the arrangement makes it possible to provide an efficient pothead or cable insulator which may be readily installed without wiping joints or employing specially skilled labor. With the improved pothead it is also not necessary to run the chance of damaging the cable through heat where a wiped joint is necessary. In this form of pothead it is not necessary to secure fittings together which is very difficult owing to the friction. as all clamping is done through bolts 30, or other suitable means.

Since the outer surface of the dielectric members recedes gradually from the cable, charging current will flow through so that discharge will not take place along the insulation. With this class of construction it is possible for the porcelain to gradually pick up the electrical stress so that the cable will not break down at the point of entry. While the insulator is made of a material such as porcelain which has a diel ctric flux constant of approximately 6 as compared to approximately 2 for the cable insulation, it is possible to build potheads which will develop the effective insulation of the cable very easily and without the danger of charging current flowing along the surfaceas in the case where varnished cambric, paper or other insulation must be depended upon for building up the cable and preventing discharge.

Fig. 4 shows still another modification.

In this case the upper clamping flange 31 made in two or more parts so that it will pass over the projection or shoulder 32 on the insulator. The outer surface in the lower clamping bell l8 and not covered by the lead sheath 13 or gasket between it and the insulator is covered by a metallized surface 33. In order to prevent the accumulation of water, a vent 34 is provided with a

drip lip

35 and 36.

I claim 1. The combination with a cable comprising a conductor having an insulating covering and an outer protecting sheath, of a rigid dielectric sleeve, surrounding said covering at the end of said sheath the terminal portion of said sheath beingsecured directly to the outer surface of said sleeve.

2. The combination with a cable comprising a conductor, an insulating covering for said conductor and an outer metal sheath, of a dielectric sleeve surrounding a portionof said insulating covering andihaving a tapered end extending beneath said sheath, and means for clamping said sheath against the outer surface of said sleeve.

3. The combination with a cable comprising a conductor, an insulating covering for said conductor and an outer metal sheath, of a dielectric sleeve surrounding a portion of said insulating covering and having a tapered portion projecting beneath said sheath, and a metal bell overlapping said sheath and clamping said sheath against said dielectric sleeve.

4. The combination with a cable comprising a conductor, an insulating covering and of said porcelain sleeve.

6. The combination with a cable having a conductor, an insulating covering and an outer metal sheath, of a'dielectric sleeve surrounding a portion of said insulating covering and having a tapered portion extending beneath said metal sheath, a metal bell having a tapered portion engaging the outer face of said sheath opposite said dielectric sleeve, and means bearing on said dielectric sleeve for drawing said metal bell toward said dielectric sleeve to wedge the tapered portion of said sleeve toward the tapered portion of said bell and to clamp said sheath between said tapered portions.

7 The combination with a cable having a conductor, an insulating covering for said conductor and an outer metal sheath, of a dielectric member having a portion thereof engaging the end portion of said metal sheath, a member for clamping said end portion against said dielectric member, a clamping ring attached to said dielectric member, and threaded means connected with said clamping ring for drawing said clamping member toward said dielectric member to clamp said metal sheath between said clamping member and dielectric member.

8. The combination with a cable having a conductor, an insulating covering for said conductor and an outer metal sheath, of a dielectric sleeve surrounding a portion of said insulating covering and having a tapered end extending between said insulating covering and the end of said metal sheath, a terminal member connected with said conductor and mounted on said dielectric sleeve at the end thereof opposite said tapered end, a metal bell having an opening in the end thereof through which said metal sheath-extends into position between the outer face of the tapered portion of said sleeve and the inner face of the end portion of said bell, a clamping ring secured to said dielectric sleeve adjacent the larger end of said bell, and bolts for clamping said bell and clamping ring together to clamp the end of said sheath between said bell and dielectric sleeve.

9. A terminal for a cable comprising a metal bell having an opening through the smaller end thereof for receiving a cable, a porcelain sleeve having a tapered end portion extending into said bell and having the upper portion projecting beyond said bell, a terminal for said cable mounted on the upper end of said sleeve, a supporting bracket for said bell, a clamping ring engaging a shoulder on said dielectric sleeve, a covering for said cable extending through the smaller end of said bell and held between the inner face of said bell and the outer face of said dielectric sleeve, and screws connecting said bell and clamping ring to exert a wedging force against said cable covering between said bell and dielectric sleeve.

10. A terminal for a cable comprising a metal bell, a dielectric sleeve having a tapered end extending into said bell, a cable extending through the end of said bell into the interior of said dielectric sleeve, said cable having a covering extending between said sleeve and bell, means for clamping said covering between said sleeve and bell, and a terminal for said cable carried at the end of said sleeve opposite said bell, there being an openingfor filling said sleeve and bell at the upper end of said sleeve, said opening being closedby said terminal.

11. The combination with a cable having a conductor, an insulating covering for said conductor and an outermetal sheath, of a dielectric sleeve surrounding a portion of sald insulatlng covering and having a tapered end extending between said covering outer metal sheath, of a dielectric sleeve having a tapered end extending between said dielectric covering and sheath, a metal bell having a tapered portion engaging the outer face of said metal sheath to clamp said sheath against the tapered portion of said sleeve, a gasket disposed adjacent said metal sheath to form a tight joint with said sleeve and bell, a clamping ring cemented to said sleeve, bolts for connecting said ring and bell, and a terminal for .said conductor at the end of said sleeve opposite said bell, said terminal having an opening therethrough to permit filling of the interior of said sleeve.

13. The combination with a cable having a conductor, an insulating covering, and an outer metal sheath, of a dielectric sleeve surrounding a portion of said covering and having a tapered end extending between said covering and sheath, a metal bell having a tapered portion for clamping said sheath against said sleeve, the outer surface of said sleeve having a coating of conducting material thereon, and means for clamping said bell against said sheath, said bell having a perforation therein to permit moisture to drain from the interior thereof, and bafiies for preventing entrance of moisture into the space between said bell and dielectric sleeve.

14. The combination with acable having a sheet metal covering, of a porcelain sleeve forming a terminal housing for said cable, said sleeve having a tapered end extending beneath said covering, and means for clam ing said covering to said tapered end, said clamping means comprising a member bear ing on said covering, a second member hearing on said sleeve, and screws for drawing said members together. 1

15. The combination with a cable having an insulating covering and an outer metal sheath of a dielectric sleeve of solid material connected at one end thereof directlyto said sheath and a terminal member connected with the end of said cable and mounted on the other end of said dielectric sleeve.

16. The combination with a cable having an insulating covering and an outer metal sheath of a solid dielectric sleeve through which a portion of the end of said cable extends, means for securing the end of said sheath directly to one end of said sleeve to forma tight joint between said sleeve and sheath and a terminal member mounted on the opposite end of said sleeve and connected with the end of said cable. 17. The combination with a cable compris-- ing a conductor, an insulating covering and an outer metal sheath of a dielectric sleeve of solid material surrounding a portion of the end of said conductor and covering, one end of said sleeve being tapered and extended between said sheath and said covering, means :tor clamping said sheath to the tapered end of said sleeve and a terminal member secured to said conductor and mounted on the other end of said sleeve.

18. The combination with a cable comprising a conductor, an insulating covering and an outer, metal sheath, a portion of the end of said cable having the outer sheath removed therefrom, of a porcelain sleeve surrounding the portion of said cable from which the sheath is removed, said sheath being gradually flared outwardly at its end, the end of said sleeve being tapered and extending between the flared portion of said sheath and said covering, a metal bell enclosing the tapered end of said sleeve, a clamping member arranged-to bear on said sleeve and press said metal bell against said sheath to clamp said sheath to the tapered end of said sleeve and a cap secured to the opposite end of said sleeve and electrically connected with said conductor and forming a terminal member for said conductor.

In testimony whereof I have signed my name to this specification on this 30th day of July, A. D. 1926.

ARTHUR O. AUSTIN.