US3551881A - Plug-in type connector for a high current and high voltage circuit - Google Patents

Description

1970 A. M. LOCKIE ETAL 3,551,881

PLUG-IN TYPE CONNECTOR FOR A HIGH CURRENT AND HIGH VOLTAGE CIRCUIT 2 Sheets-Sheet 1 Filed Marqh 28, 1968 FIG.

INVENTORS Arthur M. Lockie 8 Merrill G. Leonard Dec. 29, 1970 A. M. LOCKIE TAL 3,551,881 -IN TYPE CONNECTOR FOR A HIGH CURRENT PLUG AND HIGH VOLTAGE CIRCUIT 2 Sheets-Sheet 2 Filed March 28, 1968 FIG.4.

United States Patent O 3,551,881 PLUG-IN TYPE CONNECTOR FOR A HIGH CURRENT AND HIGH VOLTAGE CIRCUIT Arthur M. Lockie, Sharpsville, Pa., and Merrill G.

Leonard, Fowler, Ohio, assignors to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Mar. 28, 1968, Ser. No. 716,841 Int. Cl. H01r 13/52 US. Cl. 339112 1 Claim ABSTRACT OF THE DISCLOSURE A plug-in type connector for high current-high voltage distribution circuits comprising a stationary contact member and a plug-in contact member, and means for cooling gas generated when an arc occurs between the stationary contact member and plug-in contact member during closing of the circuit.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to connectors wherein a plug-in member is plugged into a stationary member to make an electrical circuit and, more particularly to a plug-in type connector for connecting a distribution transformer to a high current-high voltage power transmission line.

Description of the prior art In the prior art plug-in type connectors for connecting a distribution transformer to a high current-high voltage transmission line, the connector usually comprises a protruding stationary contact connected to the transmission line with a protruding rubber insulating member surrounding the stationary contact. The stationary contact is usually hollow to provide for plugging the movable or plugin member into the stationary contact. The plug-in member is usually surrounded by an insulating sleeve of rubber or some other good insulating material. In order to plug the plug-in member into the stationary member it is necessary to stretch the rubber or insulating housing of the plugin member over the protruding rubber or insulating member of the stationary contact. With this type of construction, if an arc occurs between the contacts, when the stationary contact is contacted by the movable contact, the hot gases generated by the arc will build up sufficient pressure to distort and sometimes rupture the rubber sleeve or housing surrounding the movable or plug-in contact. In some cases the high temperature are builds up enough pressure to actually blow the movable or plug-in member away from the stationary contact. This explosive force is sometimes sufficient to burst the sleeve or housing, or in other ways to destroy it or make it useless. The high temperature gas stream of this are is a good conductor of current; and, if the connector is close to a ground point, the arc may form a circuit from the connector to ground which is very dangerous and undesirable. This objection to the prior art connectors is eliminated by this invention by providing a vent having one end adjacent the point of contact of the stationary contact member with the movable or plug-in contact member, and with the other end of the vent connected to cooling means wherein the hot gases of the arc stream are cooled before they are released into the atmosphere. The cooled gases will then not conduct current and will not provide a circuit to the nearest ground, as is the case with the high temperature are gases.

SUMMARY OF THE INVENTION This invention provides an improved plug-in type connector for connecting electrical apparatus such as a distribution transformer to a high voltage distribution cable.

3,551,881 Patented Dec. 29, 1970 also protected with a rubber or other insulating sleeve. To

plug the plug-in member into the stationary contact member the rubber or insulating sleeve of the movable contact member must be stretched over the protruding protected rubber or insulating member for the stationary contact member. This results in relatively high friction drag, so it is ditlicult to push the contacts together with a quick positive movement, and often upon momentary contact of the movable contact member with the stationary contact member an arc will start. This are generates high temperature gases which expand with explosive forces. To prevent these high temperature gases from blowing the movable contact member away from the stationary contact member and possibly ruining the movable contact member a vent is provided which has one end thereof adjacent or near the point of contact between the stationary contact member and the movable contact member and with the other end of the vent connected to a cooling arrangement for cooling the hot gases generated by the high temperature arc. This cooling arrangement may take many different forms as long as it sufliciently cools the hot gases of the arc to a temperature at which they do not provide a good conductor of electricity. This cooling means may take the form of a chamber which is connected to the end of the vent opposite the end adjacent the contacts, which chamber will collect the hot gases generated by an arc and restrain the gases and gradually release the gases to atmosphere after they have cooled to a point wherein they no longer provide a good conductor for current. This cooling means may also take the form of a muffler connected to the end of the vent opposite the end adjacent the contact members, which mufiler restricts the flow of the hot gases for a period of time long enough to permit the hot gases to cool to a temperature wherein they may be released to atmosphere without danger of them providing a current path to ground. In both cases, the outside of the chamber and the outside of the mufiler cooling means are exposed to ambient temperature which assists in reducing the temperature of the hot gases to a safe temperature before releasing them to the atmosphere. The chamber or mufller may be made of some good electrical insulating material, such as polyester glass, or other suitable material.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation, with parts broken away for clarity, illustrating one embodiment of this invention;

FIG. 2 is a sectional view taken along line 11-11 of FIG. 1;

FIG. 3 is a plan view, partially in section, illustrating a second embodiment of this invention;

FIG. 4 is a plan view, partially in section, illustrating a third embodiment of this invention; and

FIG. 5 is a plan view, partially in section, illustrating a still further embodiment of this invention.

DESCRIPTION OF PREFERRED EMBODIMENTS Throughout the description of the drawings which follows, like reference characters illustrate like parts in each of the different figures.

Referring to FIG. 1 of the drawings, this figure illustrates a T-type plug-in connector 10 for connecting a high voltage-high current transmission line 12 to the distribution transformer 15.

The T-connector comprises a stationary contact as sembly 14 which is electrically connected to the transmission line 12. The contact assembly 14 comprises four spring-like members 16 which are collectively connected to the transmission line 12 and are arranged in substantially a circle, as best illustrated in FIG. 2. The stationary contact assembly 14 is surrounded by rubber or other insulating member 18 which protrudes from the insulation 22 of the transmission line 12 and completely surrounds the stationary contact assembly 14. A vent 20 is provided through the insulation 22 around the high voltage cable 12. One end 24 of the vent 20 terminates in the space or enclosure 13 provided by the circular arrangement of the stationary contact fingers 16 and the other end 26 of the vent terminates exteriorly of the insulation 20 around the cable 12. A chamber 28 is connected to the end 26 of the vent which extends exteriorly of the insulation 22 around the cable 12. This chamber 28 has a fairly large volume and the exterior of the chamber is exposed to the ambient temperature. Small bleed holes 30 are provided through the walls of the chamber 28.

The high voltage-high current transmission line 12 may be connected to the distribution transformer 15 by means of a plug-in member 40. The plug-in member comprises an electrical conducting element 42 which is surrounded by a rubber insulating sleeve or housing 44. The conductor 42 is connected to a high voltage cable 44 which in turn is connected to a high voltage bushing 46 of the transformer 15. The other terminal of the transformer 15 is connected to ground at 48. The insulating sleeve or housing of the plug-in member 42 is slightly smaller than the protruding insulating member 18 of the stationary member 14, so that when the plug-' in member 42 is plugged into the stationary contact member 14 to connect the transformer 15 to the transmission line 12 the insulating sleeve or housing 44 for the plug-in contact 42 must be stretched over the protruding insulating member 18 for the stationary contact assembly .14, and thereby provides a good electrical contact. At the same time, the housing 44 makes a tight fit over the protruding member 18, which thus makes a moisture proof, air tight housing or enclosure about contacts 14 and 42.

if not vented or disposed of will blow the movable contact structure away from the stationary contact structure and oftentimes injures or destroys the protecting sleeve or housing 44 of the movable contact member. However, with the structure disclosed this cannot occur because any hot gases generated by an are are vented away from the contacts 14 and 42 through the vent 20. These gases are trapped in the chamber 28 and cooled to a temperature wherein they no longer provide a good conductor. If these hot gases are released to atmosphere directly they will provide a current path for the arc to the nearest ground. However, after these gases have been cooled to a temperature where it is safe to release them to the atmosphere, they are gradually vented to the atmosphere through the very small vent holes 30 provided in the reservoir 28. This structure not only prevents the high temperature high pressure gases generated by the are from damaging or destroying the connector but it also provides for means for safely discharging these gases to the atmosphere without providing an arc circuit from the contacts to the nearest ground. If the gases are vented directly to the atmosphere and an arc is allowed to form from the contacts to ground, in all probability the connector would be melted and destroyed before the arc is extinguished by the operation of back-up protective devices on the line.

FIG. 3 of the drawings illustrates a second embodiment of this invention. The structure of FIG. 3, except for the means for cooling the high temperature-high pressure are gases comprising a baflie or muffler 50 instead of a chamber, is similar to that disclosed in FIG. 1. As seen from FIG. 3 any high temperature-high pressure gases generated by an are between the contacts 14 and 42 are vented into a muffler 50. The mutfier 50 contains a plurality of baffies 52 extending downwardly and a plurality of baffles 54 extending upwardly which provides a tortuous path for the gases. This tortuous path will provide cooling for the gases before they are discharged to the atmosphere at 56. The outside of the muffler 50 is exposed to ambient temperature which assists in cool ing the hot gases before they are released to the atmosphere.

FIG. 4 illustrates a still further embodiment of the invention. This embodiment utilizes a bafile or mufiler 50 of the type disclosed in FIG. 3 and also provides a chamber or reservoir around the muffler 50 for further cooling and restricting the flow of the gases after they have passed through the muffier 50. The reservoir 60 is also provided with very small bleed holes or orifices 62 for bleeding the cooled gases from the reservoir 60 when the pressure builds up sufficiently in the reservoir 60.

FIG. 5 illustrates an embodiment of the invention wherein a chamber or reservoir is provided inside the sleeve 40 which surrounds the plug-in contact 42. The contact 42 is centered in this chamber 70 by means of a spider member 72.

In the embodiment of FIG. 5, if an arc ocurs between the contacts 42 and 18, the hot arc gases will rise into the chamber 70 inside the sleeve 40. After the gases have cooled in the chamber 70, they are bled back to the enclosure 13 between the contact structure .14 and the end of the contact member 42 through the spaces 17 between the spring fingers 16, see FIG. 2. The cooled gases are then slowly bled from the encolsure 13 through the vent 20 to atmosphere. The vent 20 has substantially the same configuration in this embodiment as in the embodiment of FIGS. 1, 2, 3 and 4; except, that it has a very small cross-section. The purpose of the small cross-section of the vent 20 in this embodiment is to force the hot are gases to rise into the chamber 70 and thereby be cooled before they are released through the vent 20 to the atmosphere.

From the foregoing description taken in connection with the drawings, it is seen that this invention has provided a plug-in type connector for connecting a high voltage-high current transmission line to a distribution transformer or the like; wherein, the distribution transformer or the like may be plugged into the high voltage transmission line with a fault on the transmission line and if an arc should occur between the stationary contact member and the movable contact member of the connector the high temperature-high pressure gases generated by the arc may be vented from the connector and discharged to the atmosphere without danger of having the high temperature-high pressure gases of the arc damage the connector or provide a current path from the connector to the nearest ground. It is very important that the arc is not permitted to provide a current path from the connector to the ground because when an arc occurs from the connector to ground the circuit including the arc may become a very high kva. circuit which is limited only by the impedance of the transmission line and the current drawn often becomes so high that the connector will be completely melted and destroyed. This invention provides an effective and economical means for preventing any such destructive are from developing from the connector to ground, if an arc should occur when the plug-in connector element is plugged into the stationary contact of the connector.

We claim as our invention:

1. A connector for connecting a high voltage conductor to a branch conductor, said connector comprising a first body member having a hollow electrical contact assembly mounted therein, a second body member having a contact member mounted therein, the contact member of said second body member being insertable into the hollow contact structure of said first body member, a first enclosure formed by said hollow contact structure and one end of the contact member of said second body member when said contact member of said second body member is inserted into said hollow contact structure, a second enclosure in said second body member, said second enclosure surrounding said contact structure of said second body member, said second enclosure providing a gas cooling chamber for gases generated when an arc occurs between said hollow contact structure and the contact structure of said second body member, passage means connecting said second enclosure to said first enclosure, said first body member having a passage therein, said passage in said first body member having one end communicating with said first enclosure and another end open to atmosphere exteriorly of said first body member, said passage in said first body member serving to vent cooled gases from said second enclosure to atmosphere.

References Cited UNITED STATES PATENTS 2,223,975 12/1940 Traver 200-449 1,535,148 4/1925 De Hart 339-111 2,802,998 8/1957 Bauer 339--111 3,374,331 3/1968 Brockhaus et al. 339-111X 3,413,592 11/1968 Link 339-l11 RICHARD E. MOORE, Primary Examiner US. Cl. X.R.

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