US3284563A

US3284563A - Bushing protective hood and connector

Info

Publication number: US3284563A
Application number: US502025A
Authority: US
Inventors: Peter W Muschong
Original assignee: Central Transformer Corp
Current assignee: Central Transformer Corp
Priority date: 1965-10-22
Filing date: 1965-10-22
Publication date: 1966-11-08
Anticipated expiration: 1983-11-08

Description

NOV. 8, 1966 w, MUSCHONG 3,284,563

BUSHING PROTECTIVE HOOD AND CONNECTOR Filed Oct. 22, 1965 United States Patent BUSHING PROTECTIVE HOOD AND CONNECTOR Peter W. Muschong, St. Louis, Mo., assignor to Central Transformer Corporation, Pine Bluff, Ark, a corporation of Arkansas Filed Oct. 22, 1965, Ser. No. 502,025 7 Claims. (Cl. 174145) This invention relates to a device for protecting a high voltage terminal of a transformer and for connecting the bared end of a conductor to a transformer bushing.

Among the several objects of the invention may be noted the provision of a protective hood and connector for transformers which minimizes exposure of electrically live parts; the provision of a hood and connector for terminals of transformers which is enclosed except for a single opening for a conductor and a single opening for a gap electrode; the provision of a hood and connector having only two openings for a conductor and electrode which is capable of receiving a conductor from two positions 180 apart without changing the mounting of the connector on a transformer cover bushing; the provision of a hood and connector device for mounting on cover bushings of transformers which is capable of locating the spark gap electrode at two positions 180 apart without changing the mounting of the device on the cover bushing or requiring a change in its connection to a conductor; the provision of a hood and connector for transformer bushings wherein maximum spacing of the conductors may be obtained; and the provision of a protective hood and connector device having a cover which cannot be accidentally removed. Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the constructions hereinafter described, the scope of the invention being indicated in the following claims.

In the accompanying drawings, in which one of various possible embodiments of the invention is illustrated,

FIG. 1 is a plan view of a transformer illustrating two of the protective hoods and connectors of the present invention;

FIG. 2 is an enlarged plan view of a protective hood and connector of this invention with the cap removed;

FIG. 3 is a vertical section showing the connector mounted on a cover bushing of a transformer; and

FIG. 4 is a section of the-hood and connector per se taken along line 44 of FIG. 3.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Referring now to FIG. 1 of the drawings, two protective hoods and connectors 1 of the invention are shown mounted in spaced relation on the cover of a'conventional distribution transformer 3. High voltage or primary insulated conductors 5 for transformer 3 are received by the hood and connectors 1, a bared end of each of the conductors being electrically and mechanically connected to respective cover bushings 7 (FIG. 3) of transformer 3. Shown mounted on the side walls of transformer 3 are two lightning arestors 9 each of which has an electrode 11 projecting toward the connectors 1. There is a small gap between the electrodes 11 and the connectors 1.

Referring now to FIGS. 2-4, the connectors 1 generally comprise a connector body 13 which includes a metallic base 15 adapted to be attached to cover bushing 7 and an elongate upwardly projecting stem portion 17 which receives the bared end of conductor 5. Conductor 5 is secured to the connector body by clamp structure generally designated 19. A gap electrode 21 projects from a portion of the clamp structure 19 and the outer end of electrode 21 is positioned closely adjacent but spaced from the electrode 11 of the lightning arrestor 9.

A hood or casing 23 surrounds the connector body 13 and has tWo

elliptical openings

25 and 27 therethrough in the same horizontal plane. Conductor 5 is passed through one of the openings and the gap electrode 21 projects through the other. There is a cap 29 mounted on stem 17 and enclosing the upper end of casing 23. Cap 29 forces the upper portion of clamp structure 19 against conductor 5 for clamping the conductor in the connector.

More specifically, the connector base 15 comprises a circular disk 31 projecting radially outwardly from the lower end of stem 17. An annular skirt 33 depends from the periphery of disk 31 and fits around the upper end of the cover bushing 7. A tapped hole 35 in connector body 13 opens to the bottom of disk 31 and receives a threaded stud 37 (FIG. 3) on cover bushing 7 for attaching the connector to the bushing.

Stem 17 projects from base 15 perpendicularly relative to the plane of the circular portion 31 of the base. The conductor 5 is received by a hole 39 extending through the stern transverse to the length of the stem. A lower clamping jaw 41 projecting from opposite sides of the stem 17 has a generally arcuate groove 43 in its upper surface which is axially aligned with the lower portion of hole 39 in the stem. If desired, the groove 43 may taper downwardly from the center of stem 17 to the outer edges of jaw 41 to facilitate passing of the conductor 5 through the stem. The axis of jaw groove 43 is generally parallel to the axis of the hole 39 in stem 17.

In addition to clamp jaw 41, the clamp structure 19 comprises a clamp member 45 which is integral with gap electrode 21. There is a .hole 47 through clamp member 45 which is sufficiently large relative to stem 17 to permit clamp member 45 to move freely on the outer end portion of the stem, thereby permitting it to be rotated or moved axially toward and away from the clamp jaw 41. A clamp jaw 49 on clamp member 45 has a groove 51 along its lower surface which extends the full length of jaw 49 and faces the groove 43 in jaw 41. The groove 51 is substantially perpendicular to the axis of hole 47. The elongate gap electrode 21 projects from clamp member 45 at an angle of approximately to the length of groove 51 and also at approximately 90 to the axis of the hole 47 in the clamp member. Due to this relation the electrode gap 21 is always projecting perpendicular to the axis of conductor 5 and is perpendicular to stem 17. The

holes

25 and 27 in casing 23 are positioned 90 apart as shown in FIG; 2. Since clamp member 45 is freely rotatable on the outer end of stem 17, conductor 5 can be passed through either one of the

holes

25, 27 and the gap electrode 21 can be positioned so that it projects through the other hole.

Clam p member 45 'has a narrow, arcuate recess 50 extending outwardly from hole 47 adapted to at least partially receive :a shoulder 52 :on stem 17. When shoulder 52 is in recess 50, the clamp member 45 is locked against rotation relative to stem 17. This prevents inadvertent notation of gap electrode 21 when cap 29 is forcing jaw 49 toward jaw 41. However, clam-p member 45 can be freely rotated to move electrode 21 between its two positions apart by lifting the clamp member above shoulder 52.

The casing 23 is generally cylindrical in shape and is preferably made of an insulating material such as porcelain. At the lower end of casing 23 there is an enlarged skirt portion designated 53 which surrounds the skirt 33 of the connector body and the upper end of the transformer bushing 7. An annular shoulder 55 between skirt 53 and the upper portion of the casing rests on the disk 31 of the connector base. The casing 23 is rotatable to any position relative to the connector body. Weep holes 57 above shoulder 55 communicate with similar weep holes or recesses 59 beneath shoulder 55 to provide passages for water or moisture from the inside of casing 23 to the exterior of the connector.

Stem 17 above the hole 39 is threaded along two portions of its length as shown at '61 and 63. The threads 61 are separated from threads 63 by an unthreaded area in relief designated 65.

'Ilhere is an insert 67 molded in cap 29. A hole 69 in insert 67 is tapped and the threads are interrupted along a break area designated 71. The threaded area 72 of insert 67 between the un-threaded area 71 and the outer end of the insert is shorter than the area 65 without threads in the stem 17. Also, unthreaded area 71 of the stem is longer than the threaded portion 63 of the stem. This construction of the stem and insert prevents inadvertent loss of the cap. When the cap is being unscrewed and the threaded portion 72 leaves the threaded portion 61 of stem 17, the cap will turn loosely on the stem without the threads engaging. The cap can be intentionally removed from the stem by lifting upwardly on the cap to engage the threads 72 with the threads 63 and then unscrewing the cap.

The lower end of insert 67 engages the top of a doubleturn lock washer 73 which surrounds stem 17 and bears against the top of clamp member 45. Thus by screwing the cap 29 toward clamp member 45, the clamp member 45 is forced against conductor 5.

The cap 29 has an annular recess 75 located inwardly from annular skirt 79. The upper end of casing 23 is partially received in recess 75 and the lower end of skirt 79 surrounds the upper end of the casing. Four projecting ribs 81 on the upper surface of the cap facilitate rotation of the cap.

In order to mount the hood and connector of the invention onto a transformer 3, the connector body 13 is screwed onto the threaded stud 37 of transformer bushing 7 it is tight. Casing 23 and clamp member 45 are then positioned around the stem as shown in FIGS. 3 and 4 with one of the

holes

25, 27 aligned with the axis of the hole 39 in stem 17 and with the other of .the

holes

25, 27

' and the electrode 21 positioned so that they face the electrode 1|1. As illustrated in the drawings, the gap electrode 21 projects through hole 27 and the hole 25 is aligned with hole 39 in stem 17. Clamp member 45 is then lifted and conductor 5 is passed between clamp jaws 41, 49 and through hole 39 in stem 17.

Cap 29 is then screwed down on stem 17 to force clanop jaw 49 toward clamp jaw 41 until the conductor is firmly clamped between the jaws. Since hole 47 in clamp member 45 is somewhat larger than the threaded portion 61 of the stem, the clamp member 45 is free to move vertically or rotatably on the outer end of stem 17 without interference trom the threaded portion of the stern. On the other hand, when shoulder 52 on stem 17 is engaged in recess 50 in clamp member 45, then the clamp member can only move vertically and misalignment of electrode 21 is prevented. The hood and connector is then mounted and will shield the connection between the conductor 5 and bushing 7 of the transformer.

By removing the conductor 5 and then rotating casing 23 clockwise by 90 (as viewed from the top), conductor 5 can be passed into the connector from a direction 180 from that shown in FIGS. 2-4 and at the left in FIG. 1. The conductor would then pass through hole 27 in the casing 23 and the gap electrode 21 would project through the hole 25. This arrangement is shown for the connector 1 at the right in FIG. 1. The conductors 5 can enter connectors 1 at positions 180 from their FIG. 1 positions simply by rotating the casing 23 of the left connector 1'by 90 clockwise and rotating the other connection casing 90 counterclockwise. However, the arrangement of the connectors 1 shown in FIG. 1 is preferred since this separates conductors 5 by a maximum distance. Horizontal issuance of conductors 5 helps obtain maximum clearance between the conductors.

It will thus be apparent that casing 23 can be located at any of four positions apart and electrode 2llocked at either of two positions apart, depending on where conductor 5 is to enter the connector and the location of electrode 11 relative to the connector. This permits the connector to be used interchangeably on either the left or right cover bushings, and also permits complete versati-lity of positioning :as to cable entry and electrode location.

In some prior bushing connectors three holes 90 apart are required in the casing in order for the conductor to be passed into the connector from either of two positions 1i80 apart without changing the location of the gap electrode. When these connectors were installed there was always one open conductor hole through which birds, squirrels etc. could contact the live connections of the connector. If these birds or animals were standing on top of the transformer (which is at ground potential) then there was a short to ground which caused an outage in the transformer. Also, previous electrodes were part of the connector body. As they were fixed relative to the body, the entire cover bushing had to be loosened and rotated for alternate locations of the electrodes. These problems are eliminated with the connector of the invention since it more completely shields the electrically live parts and permits positioning of the electrode independent of the connector body.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructi-ons without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A protective hood and connector for attachment to a cover bushing of a transformer comprising a connector body adapted to be attached to the bushing, a stem on the body having a hole adapted to receive a bared end of an insulated conductor, a clamp jaw on the stem engageable with said bared conductor end when received by the stem, a second clamp jaw movable relative to the stem toward and away from the first jaw and adapted to cooperate with the first jaw for clamping a conductor therebetween, means for moving the second jaw toward the first jaw, the second jaw having an elongate gap electrode projecting from it at an angle of approximately 90 to the axis of a conductor when clamped by the jaws, and a generally cylindrical casing of insulating material positioned around the connector body, the casing having two holes located approximately 90 apart, the casing being movable between first and second positions 90 apart whereby a conductor can be passed through either one of said holes in the casing and the gap electrode can project through the other hole in the casing.

2. A hood and connector as set forth in claim 1 wherein the moving means for the second jaw comprises a cap threaded on the stem and movable toward and away from the second clamp member.

3. A hood and connector as set forth in claim 1 wherein the second clamp jaw is loosely positioned on the stem and rotatable relative to the stem between two positions 180 apart.

4. A protective hood and connector for attachment to a cover bushing of a transformer comprising a connector body having a base adapted to be attached to the cover bushing, an elongate stem projecting from the base, a hole through the stem transverse to its length adapted to receive a bared end of an insulated conductor, a first clamp jaw projecting from the stem at opposite sides of the hole in the stem, the jaw having an elongate groove in its upper surface parallel to the axis of the hole in the stcm,a clamp member loosely slideable on the outer end of said stem and :being movable toward and away from the first clamp jaw, the clamp member having an elongate second clamp jaw with an elongate groove in its lower surface for receiving said bared conductor end portion, the second jaw cooperating with the first jaw for clamping a conductor therebetween, the clamp member having an elongate gap electrode projecting from it at an angle at approximately 90 to the length of the groove in the second jaw, a generally cylindrical casing of insulating material positioned around the connector body, the casing having two holes through it located approximately 90 apart in substantially the same plane whereby a conductor can be passed through one of the holes into the casing and the gap electrode can project through the other hole in the casing, the casing being free of other holes through which a conductor or the gap electrode can pass, a cap for closing one end of the casing, said cap being threadably secured on the outer end portion of the stem to move the second jaw on'said clamp member toward said first jaw for clamping the bared end of a conductor between the jaws.

5. A protective hood and connector as set forth in claim 4 wherein the casing is rotatable relative to the stern and positionable at two positions apart.

6. A protective hood and connector as set forth in claim 4 wherein the clamp member is rotatable relative to the stem between two positions apart.

7. A protective hood and connector as set forth in claim 4 wherein both the stem and the cap have breaks in the threads elfecting their connection whereby inadvertent removal of the cap is avoided.

References Cited by the Examiner UNITED STATES PATENTS 2,664,457 12/ 1953 Joublanc. 2,883,640 4/1959 Duenke 174-145 X 2,934,593 4/ 1960 Kollinger 174-445 3,021,502 2/ 1962 Lehman.

LARAMIE E. ASKIN, Primary Examiner.

Claims

1. A PROTECTIVE HOOD AND CONNECTOR FOR ATTACHMENT TO A COVER BUSHING OF A TRANSFORMER COMPRISING A CONNECTOR BODY ADAPTED TO BE ATTACHED TO THE BUSHING, A STEM ON THE BODY HAVING A HOLE ADAPTED TO RECEIVE A BARED END OF AN INSULATED CONDUCTOR, A CLAMP JAW ON THE STEM ENGAGEABLE WITH SAID BARED CONDUCTOR END WHEN RECEIVED BY THE STEM, A SECOND CLAMP JAW MOVABLE RELATIVE TO THE STEM TOWARD AND AWAY FROM THE FIRST JAW AND ADAPTED TO COOPERATE WITH THE FIRST JAW FOR CLAMPING A CONDUCTOR THEREBETWEEN, MEANS FOR MOVING THE SECOND JAW TOWARD THE FIRST JAW, THE SECOND JAW HAVING AN ELONGATE GAP ELECTRODE PROJECTING FROM IT AT AN ANGLE OF APPROXIMATELY 90* TO THE AXIS OF A CONDUCTOR WHEN CLAMPED BY THE JAWS, AND A GENERALLY CYLINDRICAL CASING OF INSULATING MATERIAL POSITIONED AROUND THE CONNECTOR BODY, THE CASING HAVING TWO HOLES LOCATED APPROXIMATELY 90* APART, THE CASING BEING MOVABLE BETWEEN FIRST AND SECOND POSITIONS 90* APART WHEREBY A CONDUCTOR CAN BE PASSED THROUGH EITHER ONE OF SAID HOLES IN THE CASING AND THE GAP ELECTRODE CAN PROJECT THROUGH THE OTHER HOLE IN THE CASING.