US 3876911 A
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United States Patent 1 Schweitzer, Jr.
[ 51 Apr. 8, 1975  Inventor: Edmund O Schweitzer, Jr.,
 Assignee: E. O. Schweitzer Mfg. Co. 1nc.,
221' Filed: Feb. 11,1974
211 Appl. No.: 441,298
 U.S. Cl. .Q 317/58; l74/D1G. 10; 324/133; 340/253 A; 340/253 A  Int. Cl. 02h H00  Field of Search 324/51, 133, 103; 174/11 BH, DIG. 10; 335/293; 317/58;
 References Cited UNITED STATES PATENTS 25 12/1965 Ledocq l74/DIG. 1O 86 11/1970 Schweitzer 317/58 3.715.742 2/1973 Schweitzer 340/253 A Primary Examiner-James D. Trammell Attorney, Agent, or Firm-Robert R. Lockwood  ABSTRACT The housing of a high voltage connector has embedded therein a U-shaped yoke of low coercive magnetic material embracing the conductor in the housing and having a magnetizing winding thereon connected to external terminals. Adjacent the ends of the yoke and also embedded in the housing is a reed switch which is closed when the yoke is magnetized. It is also connected to external terminals. A reset tool has external terminals connected across a chargeable capacitor for connection to the winding terminals for magnetizing the yoke and connected to a lamp in series with a current source for connection to the external terminals of the reed switch for detecting whether it occupies a closed or an open position.
8 Claims, 6 Drawing Figures 1 FAULT INDICATOR SYSTEM FOR HIGH VOLTAGE CONNECTORS This invention relates. generally, to means for detecting flow of fault current in a high voltage circuit and for resetting the detecting system. It constitutes an improvement over the systems disclosed in my US Pat. Nos. 3,538,386, issued Nov. 3, 1970, and 3,715,742, issued Feb. 6, 1973.
Among the objects of this invention are: To provide fault responsive means as an integral part of a high voltage connector which comprises an insulating housing in which a conductor and the connector elements are embedded; to provide the fault responsive means in the form of a yoke of low coercive force magnetic material embracing the conductor and having a magnetizing winding thereon together with a reed switch having separable contacts that are closed when the yoke is magnetized; to embed the yoke with its magnetizing winding and the reed switch in the insulating housing; to provide external terminals for the magnetizing winding and the reed switch; to provide a fault detecting and reset tool having terminals for engaging the external terminals on the housing; to connect a capacitor in the reset tool across the external terminals thereof and to charge the capacitor from a direct current source on manual closure of a switch for energizing the magnetizing winding; and to connect a lamp in series with the direct current source and across the reed switch to determine whether it is closed or open.
In the drawings:
FIG. 1 is a view, in side elevation with a part shown in section, of fault detecting connector means in which this invention is embodied.
FIG. 2 is a view, similar to FIG. 1, at a slightly reduced scale and shows in section certain details of con struction.
FIG. 3 is a view in perspective and somewhat diagrammatic in character that illustrates the fault detecting connector means of this invention.
FIG. 4 is a diagrammatic view ofa combination indicator and reset tool for use in conjunction with the fault detecting connector means illustrated in the preceeding FIGS.
FIG. 5 illustrates diagrammatically the circuit connections employed in the combination indicator and reset tool.
FIG. 6 illustrates how remote indicating and reset means can be connected to the fault detecting connector means.
Referring now particularly to FIGS. 1 and 2 of the drawings the reference character 10 designates, generally, fault detecting connector means in which this invention is embodied. It comprises a molded insulating I housing 11 of conventional material in which is embedhigh voltage electric power distribution system. For example it may be an underground insulated conductor. The conductor extension 12 is connected to a terminal 14 which may be a terminal of a transformer, such as servation. For this purpose a bifurcated yoke of low coercive material, indicated generally at 15, is embedded in the insulating housing 11 and embraces the conductor extension 12 as illustrated more clearly in FIG. 3. The yoke 15 comprises U-shaped arms 16 and 17 which are connected at one end by a connection section 18. A magnetizing winding 19 extends around the U-shaped arms 16 and 17. On application of sufficient direct current to the magnetizing winding 19, the yoke 15 is magnetized and it retains this magnetism until it is demagnetized by flow of alternating fault current in the conductor extension 12.
Across the distal ends 20 and 21 of the arms 16 and 17 is positioned a reed switch that is indicated, generally, at 22. Like the yoke 15 with the winding 19 thereon, the reed switch 22 also is embedded in the housing 11 when it is molded. The reed switch 22 is provided with switch contacts 23 and 24 that normally are engaged when the yoke 15 is magnetized. They are separated when the yoke 15 is demagnetized. Thus, the position of the switch contacts 23 and 24, either open or closed, indicates whether the yoke 15 is still magnetized or has been demagnetized as a result of flow of fault current through the conductor extension 12.
With a view to magnetizing the winding 19 from an external source and for detecting the position of the switch contacts 23 and 24 the insulating housing 11 is provided with a flat surface 25 in which external contacts 26A and 26B are located, and shown in FIG. 3. They are connected to the terminals of the magnetizing winding 19. Likewise in the flat surface 25 external contacts 26C and 26D are located and, as shown in FIG. 3, they are connected, respectively, to the switch contacts 23 and 24. It will be understood that the flat surface 25 may be located at the bottom of a socket or other suitable locating means as may be desired.
With a view to indicating the position of the switch contacts 23 and 24 and for energizing the winding 19 there is provided a combination indication and reset tool that is indicated, generally, at 31 .in FIG. 4. In genera] the tool 31 may resemble a flashlight and may be provided with an insulated tool housing 32 that is tubular in configuration. A pair of contacts 33 and 34 project from one end of the housing 32 which contains a source of direct current in the form of three flashlight batteries 35. This particular source of direct current is referred to for illustrative purposes. One terminal 36 of the direct current source 35 is connected to the contact 34 while the other terminal 37 is connected by a manually operable switch means 38 to signalling means 39, preferably in the form of an indicating lamp, which, in turn, is connected to the other of the pair of contacts 33. The manually operable switch 38 preferably is in the form of a push button. The signalling means 39 can also be in the form of a sonic device such as a bell or buzzer.
For energizing the winding 19 a capacitor 43 is employed. It is connected across the contacts 33 and 34 and is arranged to be charged through the lamp 39 when the manually operable switch means 38 is closed.
In operation, when it is desired to test the condition of the reed switch 22, the tool 31 is manipulated to place the contacts 33 and 34 in engagement with the external contacts 26C and 26D. This is illustrated in FIG. 4. If the lamp 39 lights up, then the lineman knows that the switch contacts 23 and 24 of the reed switch 22 are closed and that the yoke 15 is magnetized. Also this advises him that no fault current has flowed through the conductor extension 12.
However, if the lamp 39 fails to light, then the lineman knows that the switch contacts 23 and 24 of the reed switch 22 are open. This indicates that the yoke is demagnetized as a result of the flow of alternating fault current through the conductor extension 12.
Under these circumstances it is desirable that the yoke 15 be remagnetized. For this purpose the lineman shifts the tool 31 to place the contacts 33 and 34in engagement with the external contacts 26A and 268. This is illustrated by broken lines in FIG. 4. The capacitor 43, which previously was charged through the lamp 39 on closure of the manually operable switch means 38 now discharges through the winding 19 to remagnetize the yoke 15.
FIG. 6 illustrates how the winding 19 can be remagnetized from a remote point and also how the position of the switch contacts 23 and 24 can be determined from the remote point. For this purpose cable means 44 in the form of a pair of conductors is connected to the external contacts 26A and 268. Then at a remote point a suitable source of direct current can be provided for connection across the cable means 44 to reset the fault detecting means. Likewise cable means 45 in the form of a pair of conductors can be connected to the external contacts 26C and 26D and connected across signalling means such as the lamp 39 in series with the direct current source 35 to indicate at the remote point whether the switch contacts 23 and 24 are closed or open.
1. Fault detecting connector means for interconnecting a high voltage alternating current conductor and a terminal comprising: an insulating housing, a conductor extension in said housing for connecting said conductor to said terminal, a yoke of low coercive magnetic material within said housing and embracing said conductor extension, winding means on said yoke for magnetizing it, switch means adjacent said yoke, said switch means occupying one position when said yoke is magnetizedand an alternate position when said yoke is demagnetized by flow of fault current through said conductor extension, terminal means exterior to and mounted on said housing, and conductor means interconnecting said winding means and said switch means to said terminal means.
2. Fault detecting connector means according to claim 1 wherein said housing is formed of moldable plastic and said yoke with said winding means thereon and said switch means are embedded in said housing.
3. Fault detecting connector means according to claim 1 wherein said terminal means exterior to said housing are connected to fault indicating means and to reset means for remagnetizing the yoke.
4. Fault detecting connector means according to claim 3 wherein said fault indicating means includes a current source and signalling means for connection across said switch means.
5. Fault detecting connector means according to claim 3 wherein said resetmeans includes a direct current source and a capacitor for connection across said winding means.
6. Fault detecting connector means according to claim 3 wherein said fault indicating means includes a series connectable direct current source and a signalling device, said reset means includes a capacitor connected to one terminal of said direct current source, and a manually operable switch is arranged to connect said series connected direct current source and said signalling device across said switch means and to connect said capacitor to another terminal of said direct current source and across said winding means.
7. Fault detecting connector means according to claim 1 wherein cable means connect said winding means and said switch means to terminal means remote from said housing for connection to fault indicating means and to reset means for magnetizing said yoke.
8. For combination with an insulating housing enclosing a high voltage alternating current conductor embraced by a yoke of low coercive magnetic material having reset winding means thereon, switch means adjacent said yoke having switch contacts operated from closed position to open position depending upon the magnetization or demagnetization of said yoke. and external contacts connected to said reset winding means and to said switch contacts; a combination indication and reset tool comprising an insulating tool housing having a pair of contacts for connection to said external contacts and across either said reset winding means or across said switch contacts of said switch means, a source of direct current in said tool housing having one terminal connected to one of said pair of contacts, signalling means carried by said tool housing and connected to the other of said pair of contacts, manually operable switch means for connecting said signalling means to another terminal of said source of direct current whereby said signalling means is energized when said pair of contacts engages said external contacts connected to said switch contacts and said switch contacts are closed, and capacitor means connected across said pair of contacts and charged when said manually operable switch means is closed whereby said reset winding means is energized and said pair of contacts engages said external contacts connected to said reset winding means.