Magnetic Safe Break Terminator Arc Suppressor

Abstract

An electrical connector including a plug having a member of arc-extinguishing material connected to an electrically conductive male element by a ferromagnetic stud and a receptacle having a sleeve of arc-extinguishing material connected to a hollow electrically conductive female element.

Description

BACKGROUND OF THE INVENTION

In electrical connectors of the type having a plug and receptacle as shown in copending application Ser. No. 748,142 , insulating members of arc-extinguishing material are positioned at the ends of the electrically conductive elements to interrupt the arc produced on disconnection of the plug from the receptacle. Repeated disconnection of the plug from the receptacle has resulted in a noticeable deterioration or erosion of the arc-extinguishing member in the plug at the juncture of the member with the electrically conductive element. Difficulty has also been encountered in connecting the arc-extinguishing member to the electrically conductive element in the plug.

SUMMARY OF THE INVENTION

The electrical connector plug of this invention is provided with an improved connection between the arc-extinguishing member and the electrically conductive element which increases the operating life of the arc-extinguishing member. This has been accomplished by using a magnetically permeable stud to connect the arc-extinguishing member to the electrically conductive male element. The stud is embedded within the arc-extinguishing member where it forms a magnetic core that directly exerts control on the arc formed on disconnection of the plug from the receptacle. Magnetic attraction of the arc to the core is believed to reduce damaging action of the arc on the extinguishing member and to facilitate arc extinction.

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

FIG. 1 is a side view in section of the electrical connector with the plug mounted on the receptacle.

FIG. 2 is a side view in section of the electrical connector showing the plug partially withdrawn from the connector.

FIG. 3 is an exploded view of a portion of FIG. 2 showing the arc in the gap between the arc-extinguishing members.

DESCRIPTION OF THE INVENTION

Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. The scope of the invention is defined in the claims appended hereto.

Referring more particularly to the drawing, an electrical connector of the type contemplated herein includes a plug 10 telescopically received in a receptacle 12 each of which includes an electrically conductive element 14 and 16, respectively. On withdrawal of the plug 10 from the receptacle 12 an arc drawn between the conductive elements 14 and 16 is interrupted by arc-extinguishing members 18 and 20 provided on the ends of the electrically conductive elements 14 and 16, respectively.

More specifically, the receptacle 12 includes a bushing 22 formed either from an organic insulating material or an inorganic material, such as glass or porcelain. The electrically conductive element 16 is formed from a hollow tube and is housed within a central recess 24 provided in the bushing 22. The element 16 is connected by means of a screw 28 to an electrical conductor 26 which is connected to a high voltage cable.

The arc-extinguishing member 20 is positioned in the end of the recess 24 in the bushing 22 at the end of the conductive element 16 and is made in the form of a sleeve. The arc-extinguishing members 18 and 20 are desirably formed from arc-extinguishing material such as Nylon, Delrin or any of the other known gas evolving arc-extinguishing materials.

The plug 10 includes an insulated hood 36 molded from any of the known insulating materials such as rubber and is generally provided with a hook eye 38 formed as an integral part of the hood 36. The electrically conductive element 14 is housed within a recess 40 provided in the hood 36 and projects outwardly into a tapered recess 32. The electrically conductive element 14 in recess 32 is connected to a terminal lug 42 crimped to the end of a high voltage cable 44. The arc-extinguishing member 18 was formerly secured to the end of the electrically conductive element 14 by inserting a reduced diameter section of the member into an aperture at the end of the element 14. The member 18 has an elongate shape for insertion into the sleevelike arc-extinguishing member 20 and the hollow electrically conductive element 16 in the receptacle 12.

The plug 10 is connected to the receptacle 12 by telescoping the arc-extinguishing member 18 into the sleevelike member 20 and pushing the plug toward the receptacle until the electrical elements 14 and 16 are in mating engagement. The plug 10 will seat on the receptacle 12 with outer surface 30 of the receptacle in sealing engagement with the surface of recess 32.

Snap release of the plug 10 from the receptacle 12 is provided by pulling on the elongated hook eye 38 to break the vacuum formed by the engagement of the surface of recess 32 with the surface 30 of the receptacle. The resistance to release of the plug 10 from the receptacle 12 may be increased by providing an annular groove 35 at the end of the receptacle and an annular ring 37 at the inner end of the recess 32. The structure described above is substantially similar to the structure disclosed in copending application Ser. No. 748,142, however, an electrically conductive coating 15 is provided around the electrically conductive element in both the plug 10 and receptacle 12.

The improvement relates to the means for influencing the path of the arc, as well as connecting the arc-extinguishing member 18 to the electrically conductive element 14. This means includes a ferromagnetic stud or core 50 embedded in the arc-extinguishing member 18 and secured to the conductive element 14. The stud 50 is formed from a ferrous material such as steel. In practice it may be provided with threads 52 and 54 at each end for anchorage. The threaded end 52 is screwed into a threaded aperture 56 at the end of the conductive element 14. The arc extinguishing member 18 is provided with a threaded aperture 58 and is screwed onto the threaded end 54 of the stud. The stud 50 provided a magnetic flow path for the magnetic field which forms about the arc. The flux in that path tends to draw the arc toward the stud. Erosion of the end 53 of the member 18 at the junction 55 with the element 14 has been reduced markedly by using the ferromagnetic core.

Although the cause of the reduction in erosion of the member 18 has not been determined, it is believed to be due to the presence of a magnetically permeable material in the magnetic field of the arc current. Referring to FIGS. 2 and 3 the plug 10 is shown partially withdrawn from the receptacle 12 with the electrically conductive members 14 and 16 separated and an arc 60 is shown in the gap 62 between the arc-extinguishing members 18 and 20. Normally, the arc is free to follow the ionized path of highest conductivity between the arc-extinguishing members 14 and 16 and tends to remain centrally disposed between the arc-extinguishing members 18 and 20. However, the ferrous material in the stud or core 50 provides a magnetic flow path in close proximity to the magnetic field around the arc. The arc 60 will be pulled or drawn toward the core 50 due to the tendency of the magnetic field around the arc to seek the shortest magnetic flow path. This prevents the arc from moving freely in the gap and is believed to relieve the nonconductive sleeve of some heat and also possible helps in extinguishing the arc sooner. Although the ferromagnetic material has been disclosed in the form of a core or stud 50, a ferromagnetic sleeve could also be mounted on the arc-extinguishing member 20.

Claims

I claim:

1. A plug for connecting a high voltage cable to a receptacle having an arc extinguishing sleeve positioned at the entry end of a hollow electrically conductive tubular member, said plug including

an electrically conductive element adapted to be inserted into the hollow tubular member,

an arc-extinguishing member secured to said element, and

a magnetically permeable core within said arc-extinguishing member for influencing the flow path of the arc drawn between the electrically conductive tubular member and said electrically conductive element on disconnection of said plug from the receptacle.

2. A plug according to claim 1 wherein said core comprises a ferromagnetic stud connecting said electrically conductive element to said arc extinguishing member.

3. An electrical connector for disconnecting high voltage conductors comprising

a receptacle having a first electrically conductive element having one end connected to a high voltage conductor and

a first member made of an arc-extinguishing material positioned at the other end of said first element,

a plug having a second electrically conductive element having one end connected to a high voltage conductor and a second member made of an arc-extinguishing material positioned at the other end of said second element, and

a magnetically permeable core embedded within said second member for influencing the flow path of the arc drawn between said first and second elements on disconnection of said plug from said receptacle.

4. An electrical connector according to claim 3 wherein said core comprises a ferromagnetic stud.

5. An electrical connector for connecting high voltage conductors comprising

an electrically insulating plug having a tubular electrically conductive element connected to one of the high voltage conductors,

a ferromagnetic stud secured to the end of said element and forming an extension thereof and a member of arc-extinguishing material mounted on said stud,

an electrically insulating receptacle having a hollow electrically conductive element connected to another of the high voltage conductors and

a sleeve of arc-extinguishing material positioned at the entry to said hollow element to telescopically receive said tubular element and arc-extinguishing member on connection of said plug and receptacle.

6. The combination of a telescopically insulated cable connector having disconnectable male and female electrical contacts electrically connected to high voltage conductors,

the female contact having a first member of arc-extinguishing material positioned at the entry to said female contact,

the male contact having a second member of arc-extinguishing material affixed to the end of the male contact,

and a magnetically permeable element embedded in one of said first and second members to aid in extinguishing the arc drawn between said contacts on separation.