US3855435A

US3855435A - Solid insulated breaker of a small size

Info

Publication number: US3855435A
Application number: US00411068A
Authority: US
Inventors: H Himi
Original assignee: Meidensha Electric Manufacturing Co Ltd
Current assignee: Meidensha Corp; Meidensha Electric Manufacturing Co Ltd
Priority date: 1972-11-01
Filing date: 1973-10-30
Publication date: 1974-12-17
Anticipated expiration: 1991-12-17
Also published as: DE2354632B2; GB1451346A; CA998412A; FR2204873A1; JPS4967167A; DE2354632C3; FR2204873B1; DE2354632A1

Abstract

A solid state material insulated breaker of a small size comprising a molded main cylinder of electrically insulating material. The main cylinder is sealed at the upper and lower ends thereof and encloses a breaker unit having a fixed and a movable contacts therein. An insulating material is enclosed in said insulating cylinder. Two electrical conductors covered with a solid state insulating material are inserted respectively through two longitudinally spaced holes in the wall of said insulating cylinder, and connected electrically to said fixed and movable contacts.

Description

Himi

1111 3,855,435 1451 Dec. 17, 1974 [75] Inventor:

1 1 SOLID INSULATED BREAKER A SMALL SIZE Hitoshi Himi, Tokyo, Japan [73] Assignee: Kabushiki Kaisha Meidensha,

Tokyo, Japan [22] Filed: Oct. 30, 1973 [21] Appl. No.: 411,068

[30] Foreign Application Priority Data Nov. 1, 1972 52 us. c1. 200/144 B, ZOO/148 o, 200/150 R 51. 1111. C1. Hlh 33/66 58 Field of Search 200/14 B, 1480, 148 R,

Japan 47-109670 3,471,669 /1969 Curtis ZOO/144B 3,571,543 3/1971 Perkins et a1. ZOO/144 B 3,751,617 8/1973 Bohlinger 200/144 B Primary ExaminerRobert S. Macon Attorney, Agent, or Firm-Waters, Roditi, Schwartz &

Nissen 57] ABSTRACT A solid state material insulated breaker of a small size comprising a molded main cylinder of electrically insulating material. The main cylinder is sealed at the upper and lower ends thereof and encloses a breaker unit having a fixed and a movable contacts therein. An

insulating material is enclosed in said insulating cylinder. Two electrical conductors covered with a solid ZOO/150 R I state insulating material are inserted respectively [561 Cite I i231 15.2511315251132 3 Z ZSZEJLEZZ leilfillfl' fi UNITED STATES PATENTS said fixed and movable contacts. 7 3,123,698 3/1964 Waterton 200/148 G r 3,147,356 9/1964 Luehring '200/144 B Claims, 6 Drawing Figures as M b l sour) INSULATED BREAKER or A SMALL srzr:

BACKGROUND OF THE INVENTION This invention relates to an electric breaker and more particularly to a solid insulated breaker or interrupter of a small size.

Recently, in the great towns, with the growth in population and the excessive density of the building and the industrial institutions, the need for the electric power has rapidly increased, but it is always very difficult to reserve the site of the transformer substation in the densely aggregated areas of the great towns. Accordingly, efforts are directed to reduce the site as well as the equipments of the transformer substation. Correspondingly, a breaker of a small size is also required, thus the insulated breaker has been manufactured in a small size instead of using air insulation requiring the long insulation distance, but by using the solid, liquid or gas insulation between the electric conductive parts and the grounded member to shorten the insulation distance.

A breaker for a small sized transformer substitution accordingto one of the above insulation methods, for example, of 7.2 K V or 24 KV classaccording to the solid state insulation has been manufactured by disposing inside the mold its live conductive parts such as lead wires, breaker unit and the like, injecting a molten electric insulation material composed mainly of the epoxy resin into the space between the mold and the live conductive parts including the breaker unit, and forming all the parts in one molded body.

In this case, even if the breakers for the small-sized transformer substation may be at equal ratings, various mold types must be prepared according to thefitting conditions of the breakers (for example, the fitting dimensions of the breaker to the face of the powerboard) or the using conditions (in'th'e open air or in a house). Namely, when the exterior form of the breaker for the small-sized transformer changes according to tively large scale production of the breaker at one andthe same electric rating is required, the adequate returns will be brought to some extent. But whenthe circuit for the breaker is of high orultra-high voltage, the breaker for the small-sized transformer substation according to the solid material insulation method is generally not requested in large quantities, and further as the molded product becomes of large size and of a complex structure, the mold therefor is very costly'and does not pay in a financial view point.

OBJECTS AND SUMMARY OF THE INVENTION Accordingly, the object of the present invention is to solve the above problems and to provide a small-sized and solid material insulated breaker or interrupter for a high voltage which can be manufactured at moderate costs without needing" any costly molding.

Another object of the present invention is to provide a small-sized and solid material insulated breaker which can be used for the transformer substation of a small size and variously manufactured at moderate costs in small quantities.

A.further object of the present invention is to provide a small-sized breaker which can be manufactured as a breaker with a housing of a desired dimension easily and in a comparatively short time.

In brief, a small-sized breaker according to the pres ent invention includes a main cylinder of electrically insulating solid material sealed at the upper and lower ends thereof and having a breaker unit enclosed therein, said breaker unit including fixed and movable contact members, two elongated insulated electric conductors passing through the wall of the main cylinder at longitudinally distant positions thereon, said conductors being at one ends connected to the fixed and movable contact members of the breaker and atthe other ends adapted to' contact the ends of bus-bars, and an electrically insulating material filled up' between said breaker unit and said main cylinder. 7

The small-sized and solid material insulated breaker according to the presentinvention may be easily manufactured by using a molded cylinder member of insulating material and a simple form and inserting at one ends the insulated conductors of a fixed length, which are connectabl'e atthe other ends, for example, to the connection lead'wires of another electric machinery and are manufactured separately, into the holes bored at the corresponding positions of the side wall of said main insulating cylinder. 2

' Other objects and advantages of the invention will become apparent from the following description taken in connection with the accompanying drawings. Further, the same reference numeral in the drawings is used to indicate the same part and the reference numeral put with a dash indicates the similar part to that indicated. by the numeral without a dash.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial vertical sectional view of a preferred embodiment of the solid material insulated and small-sized breaker according to' the present invention;

FIGS. 2 and 3 are respectively partial sectional viewsof the two different insulated conductors for the dis connecting section preferred for the breaker shown in FIGS. 5 and 6 are respectivelypartial sectional views of another embodiments of insulated conductor for the disconnecting section shown in FIGS. 2 and3 attached to the housing by suitable fixing means;

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIG. 1, there is shown a small-sized and solid material insulated breaker or interrupter, more specially a vacuum breaker according to the present invention. This breaker includes insulated

electrical conductors

12, 14 and a housing 16. v

As shown in FIG. 2, the insulated electrical conductors or leads 12, 16 are respectively formed with an elongated electric conductor 18 of a fixed length and a circumferential layer 20. Both endsof said electric conductor 18 are respectively exposed for connecting to another electric conductors. The circumferential layer 20 is provided with a cylindrical solid insulator 22 of an epoxy resin, two

capacitor cones

28,30 concentrically arranged therein and an electrically grounding cylindrical layer of greater diameter. This circumferential layer may be formed by winding a paper and the like to a suitable thickness around an elongated electric conductor 18, disposing cylindrical

electric conductor layers

24a, 24b, 24c, 24d and 26a, 26b, 26c, 26d, which have respectively diameters growing consecutively in this order, concentrically near both ends of the elongated conductor respectively so as to form two

capacitor cones

28, 30 with the top points of the cones situated near both ends respectivelyof the elongated conductor, providing as a grounding "layer a cylindrical electrical conductor having a lengthalmost equalto the axial distance between the supposed bottom faces of the two cones and having the external diameter a fixed dimension smaller than that of the circumferential layer 20, impregnating the intermediate product thusobtained with insulating material such as epoxy resin, and depositing the insulating material around the cylindrical grounding layer to a fixed thickness. The external circumference of said circumferential layer 20 is provided with screws and the external circumferential of the grounding layer 32 is such that it exist radially inside the core diameter of said screws- FIG. 3 is another modification of the insulated conductor which is connected at one end to an electrical lead of another device at the disconnecting section (not shown). In the FIG. 3, there is shown a molded product including

concentrical shield rings

34, 36 formed with the electric conductor material electrically connected to both ends of the grounding layer 32' instead of the capacitor cones shown in FIG. 2. l

In FIG. 4, there is shown a main molded cylinder 36 of insulating material used for the housing 16 of the breaker in FIG. 1. This main cylinder includes a cylindrical electric conductor layer 38 as its grounding layer buried in the wall of the cylinder 36 instead of providing a grounding layer on the outer surface thereof. F ur-..

ther for the purpose of passing the insulated conductor shown in FIGS. 3 or 4, holes or

openings

40, 42 are formed separating from each other longitudinally at a fixed distance in the wall of the cylinder. On the external circumferences of both ends of the main cylinder 36, screws are provided for receiving cylindrical sup porting members (described later) including also complementary screws formed on the inside surfaces thereof respectively. Accordingly, the external surface of the conductor layer 38 must be placed inside the core diameter of the screws provided upon the external surface of the main cylinder 36. Otherwise, the conductor layer 38 will be cut off at places corresponding to the bottoms of screws which will be provided and the corona discharge will occur when used. For manufacturing the main cylinder 36 having the conductor layer 38 inside the wall thereof, it is preferable that the conductor layer 38 should be rolled around the external circumference of molded cylinder of insulating material or around a external circumference of the cylinder produced bywinding a paper and the like to a fixed thickness around a core rod having a desired external diameter and 'then removing the core rod from the resultant article, that a paper and the like should be wound around the conductor layer thus formed, and that the intermediate product thus obtained should be impregnated with insulating epoxy resin.

Referring once, more to FIG. 1, both cylindrical supporting

members

44 and 46 of metal material, on the inside surfaces of which screws are formed, are

screwed on the external'surface of the main cylinder 36 at predetermined heights respectively. Of course, screws are formed on the external surface of the cylinder 36. In the side wall of each supporting

member

44, 46,

openings

48, 50 are provided and aligned with the

openings

40, 42, respectively, in the main insulating cylinder 36. Then, through the

openings

40, 42 of said main insulating cylinder 36 as well as through the

openings

48, 50 of said supporting

members

44, 46, both insulated

conductors

12, 14, respectively, are inserted in common.

Further, both

metal fittings

52, 54 are fitted respectively on the screw portions formed around the external circumferences of the insulated

conductor

12, 14 by the screws provided on the inside surfaces of the

cylindrical portions

52a, 54a of the

fittings

52, 54. The left side surfaces of the flange portions radially externally extending from the left ends (viewed in FIG. 1) of each

cylindrical portions

52a, 54a of said

fittings

52, 54 are fonned in a supplemental shape for the supporting

members

44, 46 and firmly attached by suitable fixing means such as

screws

56, 58 to the external side surfaces of the supporting members. Between-each of the screwed inner wall surface of the

cylindrical portions

52a, 54a of the

fittings

52, 54 and each of screw portions of the outer surfaces of the insulated conductors l2, l4, adhesive including such as a resin material and the like is filled up, and thus the fitting 52 and the insulated conductor l2 as well as the fitting 54 and the insulated conductor 14 are respectively connected mechanically fixedly in a body. Consequently, when a liquid or gas insulation medium (described later) is filled up into the housing 16, it does not leak out from between each fitting and insulated conductor, thus a perfect liquid-tight and gas tight structure is provided.

Numerals

60 and 62 indicate respectively O-rings inserted between the support member 44 and the fitting 52 as well as between the support member 46 and the fitting 54, and they prevent the leak out of the liquid insulating medium filled inside the housing 16 from between each support member' and each fitting.

Inside the main cylinder 36, a vacuum breaker unit 64 is inserted. This unit is shown as including two cylindrical

glassy containers

66, 68, a ring-shaped electric conductor portion 69 connecting the containers to each other, and electrically conductive plates or

flanges

70, 72 provided at remote ends of the

containers

66, 68. However, of course, within the

containers

66, 68, fixed and movable contacts are provided. The upper end 73 of the electric conductor connected to said'fixed contact passes throught the upper conducting plate and appears on the upper portion of the unit 64. It is inserted through conductive connecting ring 76 intoa concave provided in the lower part of a substantially trapezoid-shaped, electrically conducting medium 74. n

The right side surface (viewed in FIG. 1) of the trapezoid-shaped medium. 74 includes a concave wherein the exposed left end (in FIG. 1) of the insulated conductor 12 for the disconnecting section is inserted through the ring-shaped contact 78. On the upper surhaving a somewhat small diameter as compared with that of the main insulating cylinder 36, and it is supported on the upper surface of the main insulating cylinder 36. As is clearly shown in FIG. 1, the upper surface of the support member 44 fitted on the upper circumferential portion of said main insulating-cylinder 36 is placed at the same level as the upper surface of the flange portion 80b of'the V-shaped supporting element 80. For sealing up the upper opening of the main insulating cylinder 36, there is provided a cap 82 thereon, wherein the lower circumferential surface of the cap is contacted on the upper surfaces of the support member 44 and the supporting element 80 respectively and is attached by suitable means such as ascrew 84 and the like to the upper surface of the supporting member 44. Between the upper surface of the main insulating cylinder 36 and the lower surface of the flange portion 80b of the upper portion of the V-shaped supporting element 8,0 as well'as between the upper surface of the flange portion 80b of the V-shaped supporting element 80 and the lower surface of the circumferential portion of the cap 82, there are provided O-ring86, 88, respectively, for the liquid and gas-tight purpose.

At the lower surface of the lower conducting plate 72 of electrically conducting material for the breaker unit 64, a lower, electrically conducting medium 90 having a symmetrical section as compared with the upper medium 74 is provided integral with the electrically conducting plate 72, and it is supported by an insulating support cylindrical member 92. On the outer circumference of the lower portion of the main insulating cylinder 36, a cylindrical 'supportingmember 94 is fitted by a screw formed on the inside surface of the supporting member engaging the screwprovided on the outer circumference of the lower portion of the main insulating cylinder 36. The supporting member 94 is secured to the base plate 98 by a fitting means such as a screw member 96 and it is used as a part for attaching the breaker as a whole to the base plate 98.

At the upper center of the lower medium 90, there is provided a concave and at the central portion of the medium 90, a vertical hole 100 is formed communicating with the concave or depression of the medium. Inside the hole 100, a movable lead member 102 connected to the movable contact (not shown in FIG. 1) of the breaker unit 64 is inserted. An electrically conductive ringed contact member 103 for connecting the movable lead rod 102 and the lower trapezoidal medium 90 to each other is inserted into the depression with the rod 102 threaded therein. The lower part of the movable lead member 102 is pivoted at the upper end of a bar 104 of electrically insulating material. The lower end of the insulating bar 104 is pivoted at the tip 1100 of a crank 110 which is pivotable around an axis 108. Accordingly, by the swinging motion of the crank, the movable lead 102 may reciprocate to connect and disconnect the movable contact secured on the lead 102 to and from, respectively, the fixed contact inside the breaker unit. Numeral 112 is a casing of the crank and it is attached to the lower surface of the base plate 98.

At the right side surface (in FIG. 1) of the lower trapezoidal medium 90, there isprovided a concave or depression in which is received an electrically conductive ringed contact 114, in which, in turn, is inserted one exposed end of an insulated electrical conductor 14, similar to the insulated conductor 12, passing through the opening 42 (FIG. 4) of the main insulating cylinder 36. Accordingly, when the fixed contact and the movable contact in the breaker unit 64 are contacted, an electric passage is formed passing through the electric conductor 18 of the insulated conductor 12, the upper trapezoidal medium 74, the fixed and movable contacts of the-breaker unit 64, the lower trapezoidal medium 90 and the conductor 18 of the lower insulated conductor 14.

In the space between the cylindrical supporting

members

44, 46 and the main insulating cylinder 36, adhesive such as an epoxy resin is filled and solidified and thus both screwed portions of the

members

44, 46 and the cylinder 36 are fastened to each other in a gas and liquid-tight condition. The supporting

members

46, 94 may beformed as structually integral with each other, but when they are manufactured separately as in FIG. 1, it is convenient that the supporting member 46 may be disposed in place away from the member 44 according to the length of the breaker unit inserted into the main insulating cylinder 36. As will be clearly understood from the above descriptions, (the housing 16 of the breaker is formed with the base 98, the main insulating cylinder 36 and the cap 82. Numeral 116 is a liquid insulating medium such as an electrically insulating oil inserted into the housing. Numeral 118 is an 0-ring inserted between the supporting member 94 and the plate 98 is a supporting box 120 with the base plate fixed thereon by a screw member 122.

Now, reference is made to the voltage shares taken by the structural elements, respectively, of the breaker according to the present invention. Firstly, attention is directed to the insulated electric conductors l2 and 14. Obviously, as seen in FIG. 1, the insulated conductors l2, 14 are, at the left portions thereof inserted into the liquid insulating medium 116 inside the housing 16, and connected at the left exposed ends thereof to the upper and lower

trapezoidal mediums

74, 90 through the corresponding ringed

contacts

78, 114, respectively. Further, the left end portions of the soild

circumferential layers

20, 20 for the upper and lower insulated conductors ,12, 14 are at the outer surfaces thereof, respectively, contacted with the liquid insulating medium 116 in the housing 36. Now, assume that the right half portions of the conductors l2, 14 are inserted in liquid insulating medium in the casings of anvoltage in respect to ground is applied to the insulated conductor 12 through the corresponding disconnecting switch from a source of power. The insulated conductor 12 has a pair of capacitor cones or shield rings as shown in FIGS. 2 or 3 embedded in the circumferential layer or 20', respectively, so that a predetermined dielectric strength may be obtained along the external circumference of the circumferential layer 20 of the insulated conductor 12 between the left exposed conductor portion of the insulated conductor 12 and the end edge 38a of the grounding layer 38 of the main insulating cylinder 36. Accordingly, the creeping dielectric strength of the insulated conductor 12 portion in the housing 16 is sufficiently kept. This applies also to the lower insulated conductor 14. i i

Then, the creeping dielectric strength is referred in connection with the opening 40 of the main insulating cylinder 36. As shown in FIG. 1, in the wall of the main insulating cylinder 36, the grounding layer 38 is concentrically provided. Accordingly, a predetermined dielectric strength is required, for example between the edge 38a of the grounding layer 38 exposed at the opening 40 of the main insulating cylinder 36 and the right lower edge 74a of the upper trapezoidal medium 74 as well as the'right flange portion of the upper conductive plate 70 for the breaker unit 64 respectively. Apparently, the exposed edge 38 is at ground potential, andthe upper trapezoidal medium 74, the flange portion of the conductive plate 70 for the breaker unit 64 and the ring-shaped conductive portion 69 connecting the

glassy containers

66, 68 to each other are at a predetermined high voltage level. According|y,'when a flash over will occur, the passages thereof are [3,, B and 63, shown in a broken line, whichpass from respectively the lower right end portion 74a of the upper trapezoidal medium 74, the right flange portion of theconductive plate 70 and the right flange portion of the intermediate conductive portion 69, through the liquid insulating medium 116 along the opening surface of the main insulating cylinder 36, to the exposed edge 38a of the grounding layer 38. These also apply to the lower insulated conductor 14. In this case, if the distance of the liquid insulating medium between either of the upper trapezoidal medium 74 and the voltage charged conductive portions (namely the conductive plate 70 and the conductive portion 69) and the exposed edge 38a of the grounding layer, as well as the respective contours of the charged

portions

70, 69 and the upper trapezoidal medium 74 are suitably selected, a solid state material insulated and small-sized breaker having a better dielectric strength may be manufactured.

In the present embodiment, the liquid insulating medium 116 is filled up inside the main insulating cylinder, but the insulating medium is not limited to the liquid one, a gas insulating medium such as SF, (sulfur hexafluoride) gas may be used.

Further, in this embodiment, the

fittings

52, 54 threaded upon the insulated conductor l2, 14 are attached to the cylindrical supporting

members

44, 46 by fitting means such as

bolts

56, 58, but the fitting way is not limited to the just-mentioned one. For example, as shown in FIG. 5, the supporting member 44' or 46' may be provided with a screw hole directly therein and fitted in place on the exterior circumference of the main insulating cylinder 36, and then the

insulated conductor

12 or 14 may be screwed directly into the screw hole instead of using the fitting 52 or 54 shown in FIG.

1. Moreover, as shown in FIG. 6, it goes without saying that the

insulated conductor

12 or 14 may be screwed directly into a screw hole bored in the main insulating cylinder 36.

As described above, as the main insulating cylinder 36 and the

insulated conductor

12, 14 according to the breaker of the present invention are of a simple cylindrical form, the molding price is moderate. Further. if the breaker according to the present invention is requested to change in fitting or mounting conditions without changing the electric rating thereof, the insulated conductors '12, 14 can only be requested to change in length instead of changing the form of the main cylinder 16. Accordingly, the mold types can be limited to a small number, and various breakers may be economically manufactured if in a small amount. Further, on the other hand, the opening for attaching an insulated conductor may be easily formed in the side wall of the main cylinder at a certain position decided according to the using conditions, and on the other hand, an insulated conductor may be easily produced as a long or short one'according to the fitting conditions such as the fitting dimentions, for example, length to a power-board or other electric machines. Therefore, the breaker may be manufactured generally economically according to the present invention.

While the invention has been particulary described with reference to preferred embodiment, changes and modifications may be easily possible to those skilled in the art. But it is intended to cover all the changes and modifications which do not constitute departures from the spirit and scope'ofthe invention.

What we claim is:

l. A solid state material insulated breaker of a small size comprising a main cylinder of electrically insulating solid state material and sealed at the first and second ends thereof, said main cylinder'having two openings longitudinally spaced from each other in the wall thereof, a breaker unit enclosed in said main cylinder and having a movable and a fixed contacts therein, means for fixing said breaker unit in said main cylinder, two insulated electric conductors inserted through said two openings of said main cylinder, one ends of which conductors are electrically connected respectively to said fixed and movable contacts of said breaker unit, each insulated conductor including an elongated, electric conductor and a solid insulating material layer formed around thereof in a fixed thickness, means for attaching said insulated conductors, respectively, to said main cylinder and a insulating material filled into the space between said sealed main cylinder and said breaker enclosed therein.

2. A solid state material insulated breaker of a small I size as claimed in claim' 1, wherein said solid insulating material layer of each insulated conductor includes concentrically a cylindrical electrically conductive layer and two conductive rings electrically connected to both ends of said conductor.

3. A solid state material insulated breaker of a small size as claimed in claim 1, wherein said solid insulating material layer includes concentrically a cylindrical electrically conductive and two capacitor cones arranged near both ends of said solid state insulating material layer, the top point of each cone being disposed near the outer end of said insulating material layer, each said capacitor cone consisting of a plurality of cylindrical electric conductors each having almost sam length and different radius.

I 4. A solid state material insulated breaker of a small size as claimed in claim 2, wherein said main cylinder includes concentrically a cylindrical, electrically conductive layer in the side wall thereof.

5. A solid state material insulated breaker of a small size as claimed-in claim 3, wherein said main cylinder includes a cylindrical, electrically conductive layer in the side wall thereof.

6. A solidstate material insulated breaker of a small size as claimed in claim 1, wherein at least one of said means for attaching said insulated conductors to said main cylinder including a cylindrical supporting member concentrically attached to theexternal circumference of said main cylinder and a fitting member'fitted over a corresponding insulated conductor and attached to said supporting member, said fitting member consisting of a cylindrical portion concentrically applied on the external circumference of said corresponding insulated conductor and a flange portion attached to the external circumference of said supporting member.

7. A solid state material insulated breaker ofa small size as claimed in claim 6, wherein 'said corresponding insulated conductor and the cylindrical portion of said fitting member attached concentrically on the external circumference of said corresponding insulatedconductor are connected to each other by screws provided on their adjoining surfaces, respectively.

8. A solid state material insulated breaker of a small size as claimed in claim 7, wherein adhesive is filled up and solidified in the space between said corresponding insulated conductor and said fitting member applied on the outer circumference thereof. i

9. A solid state material insulated breaker of a small size as claimed in claim 1, wherein the connection between said main cylinder and said supporting member fitted concentrically on the external circumference of said main cylinder is performed by screws formed on the adjoining surfaces of said supportingmember and saidmain cylinder.

10. A solid state material insulated breaker of a small size as claimed in claim 9, wherein adhesive is filled up in the space between said main cylinder and said supporting member. a

11. A solid state material insulated breaker of a small size as claimed in claim 1, further including a base plate and a cylindrical supporting member for mounting said main cylinder on said base plate, the last mentioned supporting member being screwed concentrically on the external circumference of the second end of said main cylinder.

12. A solid state material-insulated breaker of a small size as claimed in claim 11, wherein said insulated conductor attaching means is formed integral with said supporting member for mounting said main cylinder said base plate.

13. A solid state materialinsulated breaker of a small size comprising a main insulating cylinder having two openings axially spaced from each other therein and sealed at its upper and lower ends, a breaker unit enclosed in said main insulating cylinder and having movable and fixed contacts therein, means for supporting said breaker unit, two solid state material insulated electric conductors inserted into said two openings of said main insulating cylinder and electrically connected to the movable and fixed contacts of said breaker unit,

taching including a cylindrical supporting member attached concentrically to the external circumference of said main insulating cylinder in a liquid-and gas-tight condition, said supporting member having a screwed hole in theside wall thereof, said screwed hole, when in place, being capable of aligning with the hole provided in the side wall of said main insulating cylinder, said insulated conductor being inserted through said two holes aligned with each other in a liquid-and gastight condition and electrically connected to said fixed and movable contacts of said breaker unit.

14. A solid state material insulated breaker of a small size as claimed in claim 13, wherein a cylindrical, electrically conductive layer is concentrically formed in the side wall of the main insulating cylinder.

15. A solid state material insulated breaker of a small size as claimed in claim 1, wherein a screw is formed on the internal surface of at least one of said openings provided in the side wall of said main insulating cylinder, and a screw complementary to said just mentioned screw is formed on the external circumference of the solid state material around each solid state material insulated conductor which is inserted into said screwed opening of said main insulating cylinder.

16. A solid state material insulated breaker of a small size, as claimed in claim l3, wherein an upper end of said main insulating cylinder is sealed by a cap, an upper-supporting means for said breaker unit is'provided over said breakerunit and provided'with a flange portion contacted to the upper end surface of said main insulating cylinder, said flange portion being supported respectively by the upper end surface of said main insulating cylinder and the lower circumferential surface of said cap, a lower supportingmeans for said breaker unit including a small insulating cylinder provided below the breaker unit and further a base is provided for supporting said small insulating cylinder.

l7 A solid state 'r naterial insulated breaker of a small size as claimed in claim 16, further including an upper electrically conductive medium provided between said 'upper supporting means and said breaker unit for electrically connecting said fixed contact of said breaker with a corresponding insulated electrical conductor therefor, a lower electrically conductive medium provided between said lower supporting means and said breaker unit for electrically connecting said movable contact of said breaker unit with a corresponding insulated electrical conductor therefor, said lower medium having a vertical hole at the center thereof, a movable lead of electrically conductive material and connected with said movable contact of said breaker being supported so as to reciprocate in said vartical hole, .and mean for driving said movable lead.

18. A solid state material insulated breaker of a small size as claimed in claim 17, said means for driving said movable lead includes a crank means swingable around a fixed pivot point.

19. A solid state material insulated breaker of a small size comprising amain insulating cylinder sealed at the ,upper and lower ends thereof, a breaker unit enclosed rial, said conductors passing through the wall of said;

main insulating cylinder at two axially spaced points 20. A solid state material insulated breaker as claimed in claim 19, wherein said insulating medium includes a gas material.

Claims

1. A solid state material insulated breaker of a small size comprising a main cylinder of electrically insulating solid state material and sealed at the first and second ends thereof, said main cylinder having two openings longitudinally spaced from each other in the wall thereof, a breaker unit enclosed in said main cylinder and having a movable and a fixed contacts therein, means for fixing said breaker unit in said main cylinder, two insulated electric conductors inserted through said two openings of said main cylinder, one ends of which conductors are electrically connected respectively to said fixed and movable contacts of said breaker unit, each insulated conductor including an elongated, electric conductor and a solid insulating material layer formed around thereof in a fixed thickness, means for attaching said insulated conductors, respectively, to said main cylinder and a insulating material filled into the space between said sealed main cylinder and said breaker enclosed therein.

2. A solid state material insulated breaker of a small size as claimed in claim 1, wherein said soliD insulating material layer of each insulated conductor includes concentrically a cylindrical electrically conductive layer and two conductive rings electrically connected to both ends of said conductor.

3. A solid state material insulated breaker of a small size as claimed in claim 1, wherein said solid insulating material layer includes concentrically a cylindrical electrically conductive and two capacitor cones arranged near both ends of said solid state insulating material layer, the top point of each cone being disposed near the outer end of said insulating material layer, each said capacitor cone consisting of a plurality of cylindrical electric conductors each having almost same length and different radius.

4. A solid state material insulated breaker of a small size as claimed in claim 2, wherein said main cylinder includes concentrically a cylindrical, electrically conductive layer in the side wall thereof.

5. A solid state material insulated breaker of a small size as claimed in claim 3, wherein said main cylinder includes a cylindrical, electrically conductive layer in the side wall thereof.

6. A solid state material insulated breaker of a small size as claimed in claim 1, wherein at least one of said means for attaching said insulated conductors to said main cylinder including a cylindrical supporting member concentrically attached to the external circumference of said main cylinder and a fitting member fitted over a corresponding insulated conductor and attached to said supporting member, said fitting member consisting of a cylindrical portion concentrically applied on the external circumference of said corresponding insulated conductor and a flange portion attached to the external circumference of said supporting member.

7. A solid state material insulated breaker of a small size as claimed in claim 6, wherein said corresponding insulated conductor and the cylindrical portion of said fitting member attached concentrically on the external circumference of said corresponding insulated conductor are connected to each other by screws provided on their adjoining surfaces, respectively.

8. A solid state material insulated breaker of a small size as claimed in claim 7, wherein adhesive is filled up and solidified in the space between said corresponding insulated conductor and said fitting member applied on the outer circumference thereof.

9. A solid state material insulated breaker of a small size as claimed in claim 1, wherein the connection between said main cylinder and said supporting member fitted concentrically on the external circumference of said main cylinder is performed by screws formed on the adjoining surfaces of said supporting member and said main cylinder.

10. A solid state material insulated breaker of a small size as claimed in claim 9, wherein adhesive is filled up in the space between said main cylinder and said supporting member.

12. A solid state material insulated breaker of a small size as claimed in claim 11, wherein said insulated conductor attaching means is formed integral with said supporting member for mounting said main cylinder on said base plate.

13. A solid state material insulated breaker of a small size comprising a main insulating cylinder having two openings axially spaced from each other therein and sealed at its upper and lower ends, a breaker unit enclosed in said main insulating cylinder and having movable and fixed contacts therein, means for supporting said breaker unit, two solid state material insulated electric conductors inserted into said two openings of said main insulating cylinder and electrically connected to the movable and fixed contacts of said breAker unit, respectively and means for attaching said insulated conductors to said main insulating cylinder, respectively, at least one of said last mentioned means for attaching including a cylindrical supporting member attached concentrically to the external circumference of said main insulating cylinder in a liquid-and gas-tight condition, said supporting member having a screwed hole in the side wall thereof, said screwed hole, when in place, being capable of aligning with the hole provided in the side wall of said main insulating cylinder, said insulated conductor being inserted through said two holes aligned with each other in a liquid-and gas-tight condition and electrically connected to said fixed and movable contacts of said breaker unit.

16. A solid state material insulated breaker of a small size, as claimed in claim 13, wherein an upper end of said main insulating cylinder is sealed by a cap, an upper supporting means for said breaker unit is provided over said breaker unit and provided with a flange portion contacted to the upper end surface of said main insulating cylinder, said flange portion being supported respectively by the upper end surface of said main insulating cylinder and the lower circumferential surface of said cap, a lower supporting means for said breaker unit including a small insulating cylinder provided below the breaker unit and further a base is provided for supporting said small insulating cylinder.

17. A solid state material insulated breaker of a small size as claimed in claim 16, further including an upper electrically conductive medium provided between said upper supporting means and said breaker unit for electrically connecting said fixed contact of said breaker with a corresponding insulated electrical conductor therefor, a lower electrically conductive medium provided between said lower supporting means and said breaker unit for electrically connecting said movable contact of said breaker unit with a corresponding insulated electrical conductor therefor, said lower medium having a vertical hole at the center thereof, a movable lead of electrically conductive material and connected with said movable contact of said breaker being supported so as to reciprocate in said vartical hole, and mean for driving said movable lead.

19. A solid state material insulated breaker of a small size comprising a main insulating cylinder sealed at the upper and lower ends thereof, a breaker unit enclosed in said main insulating cylinder, two electrical conductors insulated around with a solid state insulating material, said conductors passing through the wall of said main insulating cylinder at two axially spaced points thereon and connected to the corresponding points of said breaker unit, and an insulating medium filling up the space between said main sealed insulating cylinder and said breaker unit therein, said insulating medium including liquid material.

20. A solid state material insulated breaker as claimed in claim 19, wherein said insulating medium includes a gas material.