US3413592A

US3413592A - Vented safe break terminator

Info

Publication number: US3413592A
Application number: US599772A
Authority: US
Inventors: Edwin A Link
Original assignee: RTE Corp
Current assignee: Cooper Power Acquisition Corp
Priority date: 1966-12-07
Filing date: 1966-12-07
Publication date: 1968-11-26
Anticipated expiration: 1985-11-26

Description

R O T A ,N I

6 M6 9 KT W V E .R BW IE 5 EF 0 MM 2 1 D T N E V 4 2 5 2 O 8 Nov. 26, 1968 Fl G EDWIN A. LINK BY RONALD E. BARRY Attorney United States Patent 3,413,592 VENTED SAFE BREAK TERMINATOR Edwin A. Link, Waukesha, Wis., assignor to RTE Corporation, Waukesha, Wis., a corporation of Wisconsin.

Filed Dec. 7, 1966, Ser. No. 599,772 4 Claims. (Cl. 339111) ABSTRACT OF THE DISCLOSURE Disclosed herein is an electrical connector including a plug having a first electrically conductive member connected to a high voltage conductor and a receptacle having a second electrically conductive member having a passage positioned within the receptacle and being connected to a second high voltage conductor and means to relieve pressure within said passage on insertion of said first electrically conductive member into the passage.

This invention relates to electrical connectors of the plug-in type, and more particularly to an improvement in a bushing for high voltage conductors to provide greater safety.

Plug-in type connectors are well known and are used extensively for connection and disconnection of conductors. These connectors include a bushing having an electrically conductive sleeve and a plug having an outwardly projecting electrical contact. On insertion of the electrical contact into the sleeve in the bushing an electrical connection is made between the two electrical members. It is well known that just prior to making contact between the two electrical members, the members will burn creating metal vapors which in turn spue or play on the insulating members. If the insulating members are made of organic material it will also decompose to a gaseous product. Since the bushing and plug are made to enclose the contacts on connection, the metal vapors and gaseous products will be confined to the space between the bushing and plug producing a high pressure condition which is detrimental to the safety of the operator performing the connection. This is especially significant when connecting high voltage conductors if one of the conductors is short circuited. A high fault current will be set up on prestrike increasing "vapor pressure within the space between the bushing and plug to an explosive condition.

The primary object of the present invention is to provide an electrical connector which overcomes this hazard.

Another object of the present invention is to provide an electrical connector for electrical conductors that provides greater safety on connection.

A still further object of the present invention is to provide an improved safety arrangement for an electrical connector that is simple in operation and requires substantially no increase in cost.

A still further object of the present invention is to provide an improved bushing for high voltage conductors that is compatible with standard plugs for such conductors.

A still further object of the present invention is to provide an improved bushing for connecting electrical conductors which eliminates the hazard of high pressure on connection of the conductor.

These objects are accomplished by improving the structural arrangement of the bushing for a plug-in type electrical connector. A passage or recess is provided through the bushing as a continuation of a space in the sleeve or tubular electrical contact in the bushing. The end of the passage is either left open or an enlarged chamber or one-way valve is provided at the end of the passage to allow for the expansion or escape of any high pressure Patented Nov. 26, 1968 ice ' created between the electrical contact member and the electrical sleeve located within the passage in the bushing the increase in vapor pressure within the passage will either expand into the enlarged chamber or will be vented to atmosphere through the one-way valve or open end of the bushing. It is also possible to reduce the vapor pressure by cooling or condensing the vapor in the passage by positioning a mass of metallic material in the passage. Copper wool turnings have been used successfully to accomplish this result. A small slot or groove may be provided in the electrical contact member to vent the high pressure gas back through the slot in the contact member.

Other objects and advantages will become more readily apparent from the following detailed description when read in connection with the accompanying drawings in which:

FIG. 1 is a cross-sectional view of the bushing showing the expansion passage.

FIG. 2 is a view of a modified bushing showing a oneway valve at the end of the passage.

FIG. 3 is a view of another modification of the invention showing an expansion chamber at the end of the passage and also with a cooling medium in the chamber.

The electrical connector shown and described herein is similar in its basic structure and operation to the bushing or receptacle and the electrical connector shown and described in my copending application, Ser. No. 343,527, filed Feb. 10, 1964. As seen in the drawing the electrical connector includes an insulating bushing 5 and a plug-in type contact member 7 which is connected to an electrical conductor (not shown).

The bushing 10 is made from any of the known organic or inorganic insulating materials and is shown in a cylindrical form with a mounting flange 14 provided on its outer surface. A longitudinal passage 12 is provided through the center of the bushing. The bushing is shown in an aperture 18 of a wall 16 for a transformer or the like. A mounting clamp 17 is secured to the bushing after insertion through aperture 18 and screws 15 are turned against the wall until the flange abuts the other side of the wall. The mounting clamp shown is an internal mount but an outside or external mount could also be used.

An electrically conductive sleeve 20 is positioned within the passage in the bushing and projects out of one end of the bushing. The sleeve is open at both ends forming an open passage through the bushing. A high voltage conductor 38 is connected to the outwardly extending end of sleeve 20 and is held in place by brass nuts 44. An arc extinguishing sleeve 24 may be positioned at the end of sleeve 20 within the passage 12 of the bushing. The plug-in type contact member 7 includes an electrical contact member 28 which projects from an insulated housing 27 and has an arc extinguishing tip 26 secured to the end of the member. The outer edge 25 of the housing is designed to engage the bushing prior to the engagement of the contact member 28 with the electrically conductive sleeve 20. A confined chamber or space 23 is then present between the housing 27 and the bushing 10 prior to the engagement of the electrical contact member 28 and the electrically conductive sleeve 20.

When the electrical contact member is inserted into the passage in the bushing, an electrical circuit will be completed when member 28 engages sleeve 20. However, if one of the conductors is short circuited, a heavy arc may be set up between member 28 and sleeve 20 just prior to making contact due to the high voltage. The heat of the arc will increase the vapor pressure within the sleeve which will expand out through the opposite open end of the sleeve.

In FIG. 2 a modified arrangement of the bushing is shown with sleeve 20 projecting outward from the hOuSing to a greater extent than in FIG. 1. The high voltage conductor 38 is secured to the end of the sleeve by brass nuts 44 also as in FIG. 1. However, this bushing is designed for use in a transformer housing where the inner end of the bushing may be immersed in oil. The end of the sleeve is, therefore, closed at 31 and gas ports 34 are provided near the end of the passages in sleeve 20 to open the passage to the atmosphere. A flexible sleeve 36 is mounted on the outer wall of the sleeve 20 so that it overlies the gas ports. The sleeve should be made of a material which has suflicient flexibility to allow vapor that is under pressure to vent out through the gas port and under the sleeve. A sleeve of silicone rubber type valves could also be used to accomplish this same result. When the electrical contact member 28 is inserted into the bushing, a small vapor pressure build up will occur since the sleeve is closed at both ends. If there is a fault current in the line upon or during connection an arc will be created betwen the electrical contact member and the sleeve creating a substantial increase in vapor pressure in this space. This high pressure vapor will cause the flexible sleeve to move sufficiently in order to allow the gas to escape through the gas ports. The sleeve will immediately close the gas ports after the gas has escaped preventing any oil or other material from entering the bushing.

In the modification shown in FIG. 3 a portion of the sleeve 20 is shown with an enlarged chamber 70 near the end of the passage. High voltage cable 38 is secured to the end of the sleeve by nuts 44. This chamber is designed to provide suflicient volume to allow any high pressure vapor created in the sleeve 20 to expand and thus reduce the vapor pressure and eliminate the hazard of an explosion. If the volume of the chamber cannot be made large enough to allow for sufficient expansion of the vapor, a heat absorbing mass 72 may be placed in the sleeve and chamber to condense the vapors. Copper wool turnings may be used to accomplish this result.

Referring again to FIG. 1 of the drawings, a small slot or groove 80 is shown in the electrical contact member 28. This groove may be used where it is necessary to vent any high pressure vapor products back into the space 23 rather than into a transformer housing. The vent or slot is only Vs" milled cut made in the top of the longitudinal member. It extends from the end of the arc extinguishing tip 26 back to the housing 27. It is also possible to provide a slot in the sleeve 20 and are extinguishing sleeve 24 to accomplish the same result. This slot can be used with any of the other pressure relief arrangements shown in the bushings of FIGS. 1 through 3.

Although a number of embodiments of the present invention have been shown and described it should be apparent that various changes and modifications can be made herein without departing from the scope of the appended claims.

What is claimed is:

1. The combination with a plug having a first electrically conductive member connected to a high voltage conductor, of means for connecting said member to the end of a second high voltage conductor comprising:

an electrically insulating receptacle having a passage,

a hollow electrically conductive member positioned in said passage,

said member extending through said receptacle and being connected to the end of said second high voltage conductor,

and a one way valve to relieve vapor pressure within said passage on insertion of said first electrically conductive member into the passage, said one way valve including a number of gas relief ports in said hollow electrically conductive member to vent said hollow member to atmosphere and a flexible sleeve overlying said ports, the flexible sleeve allowing for the relief of gas pressure within said hollow member on insertion of said first electrically conductive member into said hollow member and preventing the ingress of any foreign matter into said hollow member.

2. The combination according to claim 1 wherein said first conductive member includes a slot to relieve vapor pressure within said passage.

3. An electrical connector comprising:

a first housing having a first electrically conductive member therein,

a second housing having a second electrically conductive member embedded therein,

said first member being insertable into said second electrically conductive member,

and relief means for relieving pressure within said second electrically conductive member when said first member is inserted therein, said relief means comprising a vent in said second electrically conductive member and a resilient sleeve closing said vent.

4. A plug having a first electrically conductive member connected to a high voltage conductor and an electrically insulating receptacle having a passage,

a second electrically conductive member positioned in said passage, said second member extending through said receptacle and being connected to a second high voltage conductor and a one way valve at the end of the passage and a slot in the first conductive member to relieve vapor pressure within said passage on insertion of said first electrically conductive member into the passage.

References Cited UNITED STATES PATENTS 1,043,759 11/1912 Fisher. 1,535,148 4/1925 De Hart 339----111 2,223,975 12/ 1940 Traver. 2,802,998 8/1957 Bauer 339-1 11 3,181,103 4/1965 Fedorick 339-112 X 3,277,424 10/ 1966 Nelson 339-1 11 FOREIGN PATENTS 685,374 3/1930 France.

917,190 8/1954 Germany.

100,563 8/ 1923 Switzerland.

RICHARD E. MOORE, Primary Examiner.