GB2295276A

GB2295276A - Leakage-responsive circuit breaker

Info

Publication number: GB2295276A
Application number: GB9509830A
Authority: GB
Inventors: Takashi Kitamura; Yoichi Yokoyama; Yoichi Kunimoto; Tomoyuki Sawada; Hirofumi Konishi
Original assignee: Matsushita Electric Works Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 1994-11-15
Filing date: 1995-05-15
Publication date: 1996-05-22
Anticipated expiration: 2015-05-15
Also published as: CN1047021C; JP3210820B2; GB9509830D0; CN1123458A; MY113065A; GB2295276B; HK1012124A1; JPH08138517A

Abstract

A leakage responsive circuit breaker comprises a plurality of movable contacts 32 each engageable with a fixed contact 31a and a current transformer CT for providing a leakage signal for actuating the tripping mechanism. The current transformer CT is disposed in the currrent path between the fixed contact and a terminal 20a for the fixed contact whereby assembly of the circuit breaker is improved. <IMAGE>

Description

LEAKAGE-RESPONSIVE CIRCUIT BREAKER The invention concerns an leakage-responsive circuit breaker that interrupts a circuit after sensing leak current, ground fault current, or other such electrical leak current flowing in distribution lines.

This type of leakage-responsive circuit breaker is ordinarily furnished with a zero-phase current transformer in the electrical pathways along the movable-side contact terminals and movable contactors, as in Japanese Patent Publication (KOKOKU) No. 4-40821.

With an leakage-responsive circuit breaker having this constitution, however, the open/close mechanism components are coupled to the movable contactors, and electric leads making up electrical pathways are inserted through the zero-phase current transformer, whereby at the least the open/close mechanism components and the movable contactors are joined together in a block with the zero-phase current transformer which consequently presents difficulty with regard to assembly.

The invention was conceived in light of such points, its purpose lying in the provision of an leakage-responsive circuit breaker with improved assembly characteristics in that assembly of the zero-phase current transformer can be conducted separately from the movablecontactor side.

In order to accomplish the aforesaid purpose, in the context of an leakage-responsive circuit breaker comprising an open/close mechanism that performs open/close action through an actuation handle and performs interruption action through operation of tripping means, a plurality of movable contactors, connected electrically to movable-side connection terminals that open and close in linkage with this open/close mechanism, a plurality of fixed contactors, connected electrically to fixed-side connection terminals that are removed from and oppose these movable contactors, and a zero-phase current transformer that is provided in the electrical pathways between the aforesaid fixed-side connection terminals and movable-side connection terminals, and that outputs an electrical leakage signal that operates the aforesaid tripping means of the open/close mechanism, the invention is an apparatus furnished with a zero-phase current transformer in the electrical pathways along the aforesaid fixed contactors and fixed-side connecting terminals. Thus, in order to separate the zero-phase current transformer from the movable-contactor side, at the least the open/close mechanism components and the movable contactors are made independent of the zero-phase current transformer, forming blocks of small numbers of parts, thereby permitting an improvement in assembly characteristics, and also facilitating implementation of countermeasures for gas arcing, which occurs easily during opening of movable contactor contacts.

The leakage-responsive circuit breaker of the invention is provided with a housing that houses the aforesaid open/close mechanism, the plurality of movable contactors and fixed contactors, and the zero-phase current transformer. The aforesaid fixed-side connection terminals are mounted at one end of this housing, and the aforesaid movable-side connection terminals are mounted in parallel at the other end, and the zero-phase current transformer is housed at the side of the housing possessing the surface to which the aforesaid fixedside connection terminals are attached. As a result, it is no longer necessary that the compartment housing the zero-phase current transformer be provided at the compartment that houses, at the least the open/close mechanism components and the movable contactors.

Compactness is enabled, since the zero-phase current transformer can be housed in the compartment provided to accomplish electrical isolation of the fixed-side connection terminals and the housing attachment surface. In addition, routing of the electric leads forming the electrical pathways for the zero-phase current transformer is abbreviated, making assembly easier to conduct.

In the leakage-responsive circuit breaker of the invention, the aforesaid housing is provided with a compartment housing the zerophase current transformer which is open at the side of the housing to which the fixed-side connection terminals are attached, and this opening is covered with a cover that blocks it from the housing attachment surface. As a result, housing of the zero-phase current transformer can be conducted without any need to consider the fixedside connection terminals attachment procedure, thereby making all the more simple an assembly possible.

Further, in the leakage-responsive circuit breaker of the invention, an electrical leakage tripping means, including a tripping magnet that operates an open/close mechanism tripping means in response to the electrical leakage signal of the aforesaid zero-phase current transformer, are housed in a compartment formed jointly with a separate housing member at the side of the aforesaid housing, and this compartment is made to communicate with the compartment housing the zero-phase current transformer. As a result, wiring of the electric leads conveying the electrical leakage signal of the zero-phase current transformer is facilitated. Because the compartment is separate from the movable-contactor-side compartment, it also facilitates implementation of countermeasures for gas arcing, which occurs easily during opening of movable contactor contacts.

In addition, in the leakage-responsive circuit breaker of the invention, following provisional fastening of the aforesaid leakageresponsive circuit breaker tripping means to the aforesaid separate housing member side, the separate housing member is joined to the housing. As a consequence, because it is possible to independently perform assembly of the separate housing to which the leakageresponsive circuit breaker tripping means have been attached, and assembly of the separate housing, simplification of assembly operations is permitted.

A preferred embodiment of the leakage-responsive circuit breaker of the invention is equipped with an interruption mechanism that, in association with a zero-phase current transformer that senses leak current, ground fault current, or other such electrical leak current flowing in an electric path, interrupts a contact intervening in the electric path in response to output of this zero-phase current transformer, and a test switch, intervening in a test circuit that causes generation of simulated leak current in the aforesaid zero-phase current transformer, wherein the aforesaid test switch comprises a pair of fixed contact plates that are connected to the aforesaid test circuit, a mobile contact plate with a fixed base end and with bifurcated free ends that respectively oppose this pair of fixed contact plates, and a test button that opposes one of the free ends of this mobile contact plate such that the one free end disengages from one of the fixed terminal plates. An operating member is ganged with the interruption mechanism opposes the other free end of the aforesaid movable contact plate, and the other free end of the movable contact plate is released from the other fixed contact plate during operation of the interruption mechanism.This constitution, though it has only a single movable contact plate, permits individual responses to the test button and to the operation member of the interruption mechanism, and makes possible the elimination of complicated shape changes in the movable contact plate, minimizes the risk of deformation arising due to the material used at the movable contact plate, and also eliminates the connection of test circuit leads to the movable contact plate, thereby minimizing thermal effects.

In addition, in this leakage-responsive circuit breaker, the bifurcated free ends of the aforesaid movable contact plate are separated by a groove that widens in the direction of the tips, and the bifurcated free ends of the aforesaid movable contact plate are widened in the direction of the base end. As a result, because of the relationship whereby the groove narrows in the direction of the fixed-end side, the distortion at the fixed-end side when the bifurcated free ends of the movable contact plate are bent will be small, enabling diminishment of the splitting that occurs particularly where the groove is deepest, and in addition making it possible to achieve a fixed-terminal-plate standoff at the free-end side.

The aforesaid pair of fixed contact plates are made into a single fixed contact plate, wherein contacting projections are formed at locations offset from the plate surface centers, and these fixed contact plates are disposed so as to have opposite plate surfaces mutually opposed, and so as to be roughly vertical to the aforesaid fixed contact plates. Accordingly, a pair of fixed contacts can be constituted from a single fixed contact plate, permitting simplification of materials control, machining, assembly, and so forth.

In addition, in a preferred embodiment of the leakageresponsive circuit breaker of the invention, a circuit breaker unit that permits a movable contactor to be freely disengaged from a fixed contactor as a result of actuation of an actuation handle, and that forces release of the movable contactor, formerly in the closed-contacts state, from the fixed contactor at the time of an abnormal current, and a tripping unit that acts on this circuit breaker unit and forces opening of the contacts of said circuit breaker unit are mounted in parallel and housed within the housing. At opposite sides of the housing not parallel to the direction in which the aforesaid circuit breaker and tripping units are mounted in parallel, separate external electric-line connection terminals for each of these units and connection terminals furnished at the tripping-unit side are shorted.As a result, routing of wiring from the power-supply side to the load side, and from the load side to the power-supply side, can be carried out with ease by way of the shorted connection terminal on the tripping-unit side. Accordingly, routing to the ground-side terminal equipment can be carried out by way of the shorted connection terminal at the tripping-unit side, thereby permitting a simplified distribution panel, when employing a distribution panel housing trunk-line and branch-line circuit breakers within a box, wherein one end of the trunk-line and branch-line circuit breakers is made the branch wiring area, while the other end is made the connection area for the incoming power-supply-side distribution lines and the connection area for the outgoing load-side distribution lines as well as the connection area for the load-side distribution lines and the outgoing load-side distribution lines, whenever equipped with distribution-line ground-side terminal equipment at the other end of the trunk-line and branch-line circuit breakers so as to simplify load-side distribution-line connection operations.

It is possible to provide electrical leakage protection of electricpath current as a result of mounting at least two sets of the aforesaid circuit breaker units in parallel, and making the tripping unit an electrical leakage unit that senses leak current or ground-fault current flowing in at least two sets of circuit breaker units and that acts on the aforesaid circuit breaker units.

In addition, as a result of providing a coupling bar that is connected electrically between the aforesaid circuit breaker unit and tripping unit, the electric path going through circuit breaker units can be routed simply.

A number of embodiments of the invention will now be described, by way of example only, with reference to the accompanying figures in which: FIG. 1 is an oblique exploded view of a circuit breaker pertaining to one enbodinent of the invention.

FIG. 2 is an oblique general view from above of the above leakageresponsive circuit breaker.

FIG. 3 is an oblique general view from below of the above leakageresponsive circuit breaker.

FIG. 4 is an oblique exploded view of a portion of the above leakageresponsive circuit breaker.

FIG. 5 is an oblique exploded view of the structure that includes the leakage-responsive circuit breaker unit and the electrical leakage indication unit within the above leakage-responsive circuit breaker.

FIG. 6 is an enlarged top view of the principal parts of the above leakage-responsive circuit breaker.

FIG. 7 is an explanatory diagram illustrating the wiring of the distribution panel with which the above leakage-responsive circuit breaker is equipped.

FIG. 8 is an electrical circuit diagram of the above distribution panel.

FIG. 9 is an explanatory diagram of the operation of the circuit breaker unit in the above leakage-responsive circuit breaker when the former is in the ON state.

FIG. 10 is an explanatory diagram of the operation of electrical leakage indication in the above circuit breaker unit in the ON state.

FIG. 11 is an explanatory diagram of the operation of the above circuit breaker unit in the OFF state.

FIG. 12 is an explanatory diagram of the operation of electrical leakage indication in the above circuit breaker unit in the OFF state.

FIG. 13 is an explanatory diagram illustrating operation when the above circuit breaker unit is in the tripped state.

FIG. 14 is an explanatory diagram of the operation of electrical leakage indication in the above circuit breaker unit when in the tripped state.

Below, an embodiment of the invention is described with reference to the figures.

Fig. 1 shows an oblique exploded view of an leakage-responsive circuit breaker in one embodiment of the invention. In the embodiment shown, a di-pole leakage-responsive circuit breaker is constituted by joining single-pole circuit breaker block 100, provided at one end with power-supply-side connection terminal 20a and provided at the other end with load-side connection terminal 20b, with single-pole leakageresponsive circuit breaker block 101, which at one side contains a shorting path that shorts power-supply-side connection terminal 20a, provided at one end, to load-side connection terminal 20b, provided at the other end, and also contains an electrical leakage interruption unit, and which at the other side contains a single-pole circuit breaker unit.

At circuit breaker block 101 , as shown in the figures, powersupply-side connection terminal 20a and load-side connection terminal 20b are respectively provided at either end of housing 10, comprising left and right housing member 1 0a and housing member lOb, which are formed from insulating material such as synthetic resin and which are butted together. Fixed contactor 31, equipped with fixed contact 31a, is connected electrically, through terminal plate 21a, to power-supply-side connection terminal 20a. Terminal plate 21b, to which one end of bimetallic element 61, making up thermal release mechanism 60, is fastened, is connected electrically to load-side connection terminal 20b.

Fixed contactor 31, together with movable contact 32 provided on movable contactor 33, make up open/close contacts 30. Movable contactor 33, in response to operation of close/open mechanism 40, to be described, opens and closes movable contact 32 with respect to fixed contact 31 a.

Movable contactor 33 is connected through connecting wire 37 made of braided wire to one end of coil 51 in electromagnetic release apparatus 50 described below. The other end of coil 51 is connected via connecting wire 38 made of braided wire to the intermediate section of bimetal [bar] 61. Accordingly, when the breaker contacts close, current flows through the main electrical path consisting up of line terminal 20a, the breaker contacts, coil 51, bimetal [bar] 61, and load terminal 20b. The bimetal [bar] 61 used here may be either the directly heated type, which bends from heat generated by itself, or the indirectly heated type, which bends when heated by a heater plate laminated to it.

Housing 10 is formed by fastening cover 10b to body 1 ova with rivets 11. That is, assembly hole 12 are bored through body 1 0a and cover 1 0b at four locations around their periphery, and cover 1 0b is fastened to body 1 0a by installing a rivet 11 in each of the assembly holes 12. Handle insertion hole 13 is formed as a rectangular opening in the upper surface of housing 10 when cover lOb is put in place against body 10a. Cylindrical bearings 14 are mounted at the inside surface of body 10a and cover lOb near handle insertion hole 13. The respective ends of handle shaft 42, on which handle 41 pivots, are inserted into the bearing holes 14a in the centers of bearings 14.

Operation member 41a provided on handle 41 is inserted through handle insertion hole 13 such that it protrudes from the upper surface of housing 10. In other words, handle 41 rotates freely around handle shaft 42 over the range of motion of operation member 41 a in handle insertion hole 13. Arc-shaped cover piece 41 b is formed at the base of operation member 41 a of handle 41 with handle shaft 42 as its center, and housing 10 is bulged outward in the area around handle insertion hole 13 to conform to cover piece 41b. Cover piece 41b slidably contacts the inside surface of housing 10 and shuts out the inside of housing 10 to be invisible even when handle 41 is rotated. Lettering is provided on cover piece 14b to indicate the open/closed state of the breaker contacts with the operation of handle 41.Link support member 41 c is mounted on the lower surface of cover piece 41 b, with shaft tabs 41d mounted on both sides of the bottom of link support 41c.

Operation member 41a and link support member 41c protrude from cover piece 41 b such that they are angled with one another rather than being aligned. Additionally, handle 41 is energized to the left as viewed in Fig. 9, by a handle return spring 43 installed around the periphery of bearing 14. One end of handle return spring 43 is secured at the right edge of cover piece 41b as seen in Fig. 9, and the other end at trip plate 44 of the switch operation apparatus described below.

Drive mechanism 40 is equipped with handle link 45, wherein shaft projections 41d provided on actuation handle 41 are inserted through bearing holes 45a formed at the tips of each foot member formed in roughly C-shape, latch plate 46, equipped with a pair of guide members 46b at both ends of flat engaging plate 46a that are roughly orthogonal to engaging plate 46a and that extend in the direction along the side rims of engaging plate 46a, and wherein handle shaft 42 is inserted through shaft holes 46c formed at the tips of guide members 46b, pivot pin 47 that is inserted through trip plate 44, the respective ends of which are inserted into bearing holes 1 5a provided at bearings 15 formed at the respective inside surfaces of housing member 1 0a and housing member lOb, and which supports trip plate 44 so as to allow it to rotate freely with respect to housing 10, and contactor link 48 that is formed so as to be roughly C-shaped, wherein one of foot members 48a passes through guide holes 46d formed in both guide members 46b of latch plate 46 and is inserted through link holes 45b provided at the bases of both foot members of handle link 45. The other leg 48b of contact link 48 is inserted through shaft openings 33a provided in movable contactor 33. A guide channel 16 curved to form a convex arc is formed below, on the inside surface of body 1 Oa.

Inserting the end of leg 48b of contact link 48 into this guide channel 16 results in the range of motion of contact link 48 being regulated by guide channel 16.

Movable contactor 33 is furnished with movable contact 32 on one end and spring receiver member 33b on the other end, and has lib 33c having shaft openings 33a, located between movable contact 32 and spring receiver member 33b, into which shaft leg 48b of contact link 48 is inserted. Movable contact point 32 is formed at the angle created by bending one end of movable contactor 33 into a general Lshape, with arc runner member 33d extending out past movable contact 32 to the end. Mounted on spring receiver member 33b is a spring seat that is inserted into one end of contact pressure spring 34, a coil spring.

The other end of contact pressure spring 34 is received in spring receiver recess 35, formed on the inner surface of body l0a, 1 Ob.

Stopper 36 is mounted on the inner surface of body 10a, facing the opening surface of spring receiver recess 35. Contact pressure spring 34 and spring receiver member 33b are inserted into the space between the inner surface of body l0a, in which spring receiver recess 35 is formed, and stopper 36. Spring receiver member 33b is energized toward stopper 36 by the spring force of contact pressure spring 34.

Trip plate 44 is formed into a shape wherein a first push pressure member 44b is mounted extending from the top end of base member 44a to one side, while a second push pressure member 44c extends downward from base member 44a, and in addition, arm 44d, 44d' is provided extending from the edge on both sides of base member 44a midway between the top and bottom in a direction generally perpendicular to base member 44a. Shaft pin 47 is inserted in the base portion of arm 44d such that trip plate 44 rotates freely around shaft pin 47. Moreover, hook notch 44e is formed in the upper edge of the leading end of arm 44d, while farther out toward the end of arm 44d than hook notch 44e, the top edge of arm 44d slopes so as to approach the bottom edge. Also, retainer notch 44f is formed on the side edge of base member 44a as an upward-cut, opening toward the side. Trip plate 44 is energized counter-clockwise (as seen in Fig. 9) by retaining one end of handle return spring 43 in this retainer notch 44f.

Latch plate 46 can be rotated freely with respect to housing 10 by handle shaft 42 and actuation handle 41, but the range of movement of latch plate 46 with respect to actuation handle 41 is regulated by the fact that leg 48a of contact link 48, which is inserted in handle link 45, is inserted in guide holes 46d of latch plate 46, and handle link 45 is pivotally supported on shaft tabs 41 d of actuation handle 41. Moreover, the lower edge of stop plate 46a of latch plate 46 can be engaged with hook notch 44e provided in trip plate 44. In the engaged state, latch plate 46 is prevented from being moved.

As described above, drive mechanism 40, made up of actuation handle 41, handle shaft 42, handle return spring 43, trip plate 44, handle link 45, latch link 46, shaft pin 47, and contact link 48, functions through the action of electromagnetic release apparatus 50 or thermal release apparatus 60 to cause the breaker contacts to open when excessive current passes through the main electrical path with the breaker terminals in the closed state.

Electromagnetic release apparatus 50 is furnished with yoke 52 which is made of magnetic material formed in an upward-opening general U shape, with coil 51 disposed within the space inside yoke 52.

Yoke 52 is furnished with a pair of side members 52a and 52b facing the two axial end surfaces of coil 51, and base member 52c, which passes below coil 51 and joins the interval between the two side members 52a and 52b. Retainer grooves 52d and 52e are formed in side members 52a and 52b, respectively. Coil 51 is disposed around cylinder-shaped coil tube 53, which is made of electrically insulating material. Flange 53a is formed in one piece at one axial end of coil tube 53, and a narrowed section 53b in which both the inside and outside diameters are smaller than those of an intermediate section in the axial direction is formed at the other axial end of coil tube 53.

Plunger 54, having a section where the diameter is larger than the inside diameter of narrowed section 53b, is disposed within the inside space of coil tube 53 such that it can move freely in the axial direction of coil tube 53. Fixed core 55 is mounted in coil tube 53 opposite plunger 54 at the flange 53a end of coil tube 53 such that a portion of it protrudes from coil tube 53. One-piece catch pin 54a is provided at one of the end surfaces in the direction of travel of plunger 54 such that it protrudes from the end surface of the narrowed section 53b of coil tube 53. Fastened at the other end is push pressure pin 57, which passes through fixed core 55 and protrudes from the end surface of coil tube 53 at its flange 53a end. Formed at the leading end of catch pin 54a is catch pin head 54b, the diameter of which is larger than at other locations on the pin.Return spring 56, made from a coil spring, is installed between plunger 54 and fixed core 55, plunger 54 being energized toward the narrowed section 53b end of coil tube 53 by the spring force of return spring 54.

The ends in the direction of travel of plunger 54 are formed with a smaller diameter than the intermediate section, one end being spring receiver 54c which is inserted into return spring 56, and the other end formed to be inserted into the narrowed section 53b of coil tube 53, the intermediate section being formed with a diameter that is larger than that of the narrowed section. In other words, pull-out stopper step 54d is formed on plunger 54, between the large diameter section and the small diameter section with catch pin 54a on it, and plunger 54 is prevented from falling out by the fact that pull-out stopper 54d is retained by a step formed on the inner circumference of coil tube 53 between the intermediate section and narrowed section 53b.

Fixed core 55 is formed such that its end near the axial end of coil tube 53 near plunger 53, which has a smaller diameter than other locations, becomes spring receiver 55a, which is inserted into return spring 56, and outer collar member 55b, which has a larger diameter than other locations, is formed on the other end. Coupler 55c is mounted at the center of said other end. When fixed core 55 is inserted into the flange 53a end of coil tube 53, outer collar member 55b contacts the end surface of coil tube 53, and coupler 55c protrudes from the end of coil tube 53. Also, push pressure pin 57, attached to plunger 54, protrudes from coil tube 53 due to its being inserted through insert opening 55d, which passes through fixed core 55 in the axial direction.

The core formed by installing plunger 54, fixed core 55, and return spring 56 in coil tube 53 as described above is installed in yoke 52 by inserting narrowed section 53b of coil tube 53 into retainer groove 52d provided in side member 52a of yoke 52, and by inserting coupler 55c of fixed core 55 into retainer groove 52e of side member 52b. Here, with the flange 53a of coil tube 53 being disposed between coil 51 and side member 52b of yoke 52, insulation between coil 51 and side member 52b of yoke 52 is assured. Moreover, because coupler 5 sic is inserted in retainer groove 52e provided in side member 52b of yoke 52, and outer collar 55b is sandwiched between flange 53a of coil tube 53 and side member 52b, fixed core 55 is magnetically coupled to yoke 52.

Electromagnetic release apparatus 50, constituted as described above, is secured in position on body 10 by inserting retainer tabs 1 7a and 1 7b mounted on the inner surface of body 1 0a into retainer grooves 52d and 52e provided in yoke 52. In addition, yoke 52 is secured to body 1 ova by fitting side members 52a and 52b of yoke 52 into yoke 52 installation grooves 1 8a and 1 8b formed on the inner surface of body 10a near retainer tabs 17a and 17b.With yoke 52 secured to body 10a, narrowed section 53b of coil tube 53 and coupler 55c of fixed core 55 are supported between the inner peripheries of retainer grooves 52d and 52e, and the outer edges of retainer tabs 17a and 17b, and coil tube 53 is fixed in position with respect to yoke 52.

In an electromagnetic release apparatus 50 constituted as described above, if current flows through coil 51, a pulling force will be created between fixed core 55 and plunger 54 so as to reduce the reluctance of the magnetic path through fixed core 55, yoke 52, and plunger 54, and if the current flowing in coil 51 is excessive in the event of a shorted load and the like plunger 54 will move toward fixed core 55 against the spring force of return spring 56. Accordingly, during such operation, the closed breaker contacts can be forcibly opened by operating drive mechanism 40, drive mechanism 40 being connected as described below.

The leading end of catch pin 54a provided on plunger 54 is inserted through catch opening 33e formed at a location between shaft openings 33a of movable contactor 33 and movable contact 32. When plunger 54 is drawn toward fixed core 55 as a result of magnetic excitation of coil 51, catch pin head 54b on the leading end of catch pin 54a catches on the rim of catch opening 33e, pulling movable contactor 33 away from fixed contact 31a. Catch opening 33e is formed as an oblong hole connecting a stop hole having a diameter smaller than that of catch pin head 54b, and a guide hole having a diameter larger than that of catch pin head 54b.This configuration allows electromagnetic release apparatus 50 to easily be linked to movable contactor 33 during assembly by guiding catch pin 54a into the stop hole after catch pin head 54b has been passed through the guide hole. Moreover, the tip of push pressure pin 57, which is attached to plunger 54, is positioned facing second push pressure member 44c of trip plate 44 such that trip plate 44 will be rotated around shaft pin 47 in the clockwise direction (as viewed in Fig. 2) when plunger 54 is drawn into motion by fixed core 55.

On the other hand, thermal release apparatus 60 is furnished with bimetal [bar] 61. One end of bimetal [bar] 61 is attached to terminal bar 21 b, and the other end is in threaded engagement with adjustment screw 62. Adjustment screw 62 faces first push pressure member 44b of trip plate 44, positioned such that when bimetal [bar] 61 bends due to excessive current flowing in the main electrical path, the tip of adjustment screw 62 pressing against trip plate 44 causes trip plate 44 to rotate around shaft pin 47 in the clockwise direction.

Adjustment window 63 is provided in an outer periphery wall of housing 10 near adjustment screw 62 in threaded engagement with bimetal [bar] 61. The degree to which bimetal [bar] 61 bends from the electrical current passing through it (its operating sensitivity) depends on variations in the composition of the material used and the location at which connecting wire 38 is connected. Therefore, in order to eliminate variations in the operating sensitivity of drive mechanism 40 (i.e., the current flowing in the main electrical path when drive mechanism 40 operates), it is necessary to adjust the amount adjustment screw 62, which is threaded into bimetal [bar] 61, protrudes from bimetal [bar] 61 on the trip plate 44 side. Accordingly, after assembly, adjustment screw 62 is operated with adjustment window 63 open.On the other hand, since once adjustment screw 62 has been adjusted, there is no need to make any further adjustments to adjustment screw 62, adjustment window 63 will be closed by closure plate 64 to prevent adjustment screw 62's being inadvertently operated, and to prevent foreign matter from entering housing 10.

Closure plate 64 is set to be generally equal to the width of adjustment window 63 (the distance between the bottoms of installation channels 63c), and generally equal to the height dimension from top to bottom of adjustment window 63. When such a closure plate 64 is inserted into adjustment window 63, the upper edge of closure plate 64 hits the upper edge of adjustment window 63, and closure plate 64 cannot be removed.

Line terminal 20a and load terminal 20b are made up of terminal clamps 22, which are formed by bending electrically conductive sheet metal, clamp screws 23 in threaded engagement with terminal clamps 22, and terminal plates 21a and 21b provided which butt against the lower ends of the clamp screws. The terminal clamps are received in square horizontal cross-section terminal chambers 24a and 24b formed in housing 10, such that the terminal clamps can be moved up and down. In other words, the height dimension of terminal chambers 24a and 24b is greater than that of terminal clamps 22, and terminal chambers 24a and 24b fit tightly around terminal clamps 22, thus allowing the clamps to be move only up and down.The heads of clamp screws 23 are formed in a truncated cone shape, with the diameter at the top smaller than that at the bottom, and screw access holes 25a and 25b, having a diameter that will allow a portion of the heads of the clamp screws to be inserted therein, but will prevent the heads of clamp screws 23 from passing through, are formed in the upper walls of terminal chambers 24a and 24b. The diameter at the top of the screw access holes is set to be smaller than that at upper end of the heads of clamp screws 23, and the diameter at the lower end of the screw access holes is set to be larger than that at the bottom of the heads of clamp screws 23.The leading ends of terminal plates 21a and 21 b are exposed to the outer side wall surface of housing 10 and bent upward, the leading ends of terminal plates 21 a and 21b being prevented from moving up and down by engaging them with fixed tab 21c, formed at the outer ends of terminal plates 21a and 21b, with fixed grooves 26, which are formed in the outer wall surface of housing 10.

In addition, terminal plate retention grooves 27, which set the positions of terminal plates 21 a and 21 b, are formed in the side walls of terminal chambers 24a and 24b which partition terminal chambers 24a and 24b from the inner space of housing 10.

Here, the distance from terminal plates 21a and 21b to the upper walls of terminal chambers 24a and 24b is set to be generally equal to the length dimension of clamp screws 23.

When the tip of a common screwdriver, etc., is inserted in screw access holes 25 and clamp screws 23 are turned, terminal clamps 22 move up or down, depending on the direction in which the clamp screw is rotated, and the distance between the terminal clamp lower member and terminal plates 21a and 21b can be changed.In other words, electrical connections to wiring material such as wire, bus bars, etc. can be made by inserting the wiring material through the connection holes 28 provided in the peripheral wall of housing 10 at locations corresponding to the spaces between the terminal plates 21 a and 21 b and the lower walls of the terminal chambers 24a and 24b, and turning the clamp screw to bring the lower members of the terminal clamps closer to terminal plates 21a and 21b, thus clamping the wiring material between the terminal clamps and terminal plates 21a and 21b.

Terminal plate 21a, which is part of line terminal 20a, has a fixed contact plate 31 which is bent downward at a point inside of housing 10 from terminal plate retainer groove 27. Fixed contactor 31 is attached at the lower end of fixed contact plate 31. Facing fixed contact 31a is movable contact 32, which is on movable contactor 33.

A portion of arc runner 71, which is made of conductive sheet material, is lapped on the surface to which fixed contact 31 a is mounted, below fixed contact 31 a on fixed terminal plate 31. Arc runner 71 is furnished with vertically oriented guide member 71a which overlaps a portion of fixed contact plate 31. The lower end of guide member 71 a continues through inclined member 71b, which slants downward at an angle, to arc suppresser member 71c, which extends along the bottom wall of housing 10 to a point below base member 52c of yoke 52. Here, arc suppresser grid 72 is disposed between locations on base member 52c of yoke 52 and arc suppresser member 71c that face each other.Arc suppresser grid 72 has a configuration wherein a plurality of arc suppresser plates 74, made of electrically conductive sheets, are supported generally parallel to each other on the inside of support bracket 73, which is made of an insulating material, generally U-shaped.

Formed in each arc suppresser plate 74 is a cutout 74a into which the lower end of movable contactor 33 is received. This arc suppresser grid 72 is disposed such than arc suppresser plates 74 are generally parallel to base member 52c of yoke 52 and arc suppresser member 71 c of arc runner 71. The shape of arc suppresser member 71 c of arc runner 71 is formed such that its width increases in steps as the distance away from inclined member 71b increases.

If movable contact 32 separates from fixed contactor 31 and an arc is created, then due to the surrounding magnetic field created as a result of the current flowing through terminal plate 2 la and movable contactor 33, and due to the magnetic force generated by the arc current, the arc will travel downward in the drawing, one end of the arc running along arc runner 71 toward arc suppresser grid 72. In other words, since fixed contact plate 31 on terminal plate 21 a faces movable contactor 33, and since the currents flowing in fixed contact plate 31 and movable contactor 33 are flowing in opposite directions, an electromagnetic force will act upon the arc in a direction so as to pull it away from fixed contact plate 31 and movable contactor 33. As a result, the fixed contact plate 31 end of the arc will run along arc runner 71 and be guided to arc suppresser grid 72.Since arc runner 33d is formed on movable contactor 33, the other end of the arc will run toward the tip of arc runner 33d. In this manner, the arc is gradually guided to arc suppresser grid 72 while being stretched out in the process.

However, a portion of connecting wire 37, which connects movable contactor 33 to one end of coil 51, is welded to side member 52a of yoke 52 closer to the breaker contacts. Therefore, when one end of the arc runs along arc runner 71, being guided to arc suppresser grid 72, the other end of the arc moves from arc runner member 33d of movable contactor 33 to base member 52c of yoke 52, causing a current to flow in a path going through base member 52c of yoke 52, side member 52a of yoke 52, connecting wire 37, and coil 51. Because the direction of the current flowing in this path is opposite to that in arc runner 71, the magnetic field generated by the currents flowing in base member 52c of yoke 52 and in arc runner 71 is such that the arc receives an electromagnetic force guiding it into arc suppresser grid 72.

In other words, intermediate member 52b of yoke 52 is capable of dual functions: it forms a magnetic path in electromagnetic release apparatus 50, and it also functions with arc runner 71 to suppress arcs. In other words, intermediate member 52c of yoke 52 functions as one of the pair of arc running plates.

At housing 10, straddling open/close contacts 30, the wall surface opposite to arc suppression grid 72 is blocked. Accordingly, if an arc is produced when open/close contacts 30 open, arc gas pressure will be highest in the vicinity of open/close contacts 30, and will be lowest in the vicinity of arc suppression grid 72. As a result, the arc gas flows toward arc suppression grid 72, and, as the direction in which the arc runs is the same as the direction in which the arc gas flows, the arc will quickly enter arc suppression grid 72.

Further, recess 102 is formed at a location above the surface at which a DIN rail or other such attachment rail, described below, is attached, at the attachment-surface side of housing 10 below terminal housing chamber 24a housing power-supply-side connection terminal 20a of housing 10. Together with another recess 102 provided in like manner at housing 10' of leakage-responsive circuit breaker block 101 described below, recess 102 constitutes the compartment housing the aforesaid zero-phase current transformer CT. Opening 102a, which communicates with cavity between terminal housing chamber 24a and the upper end member of fixed contactor 31 within housing 10, is provided at the ceiling of this recess 102. The aforesaid braided line 103 enters housing 10 through this opening 102a.

Mating groove 81, which mates with the attachment rail, is formed such that it runs in a direction orthogonal to a direction connecting power-supply-side connection terminal 20a and load-side connection terminal 20b at the housing 10 attachment-surface's bottom surface. Mating projection 82 protrudes from one of the side walls of mating groove 81, one of the overhanging members of the attachment rail being mated thereto between it and the inside base surface of mating groove 81. Furthermore, housing groove 83, which communicates with the outside surface of housing 10, is formed at the other side wall of mating groove 81. This housing groove 83 is formed in a shape such that the part of housing groove 83 interior to the lowersurface opening of housing 10 is widened relative to it.Slider 84, installed within this housing groove 83 such that it slides freely in a direction connecting power-supply-side connection terminal 20a and load-side connection terminal 20b, is arranged so as not to fall out of the lower-side opening of housing 10.

This slider 84 comprises tip 85, which engages with the overhanging members of the attachment rail, base 86, which protrudes from one end surface in the same direction as pressure member 88, described below, and central region 87, which connects tip 85 and base 86 together to form a single integral unit. Pressure member 88 is parallel to central region 87 with projections 88a, wherein a roughly Vshaped groove is formed, being provided at the tip thereof. These projections 88a are arranged so as to be admitted respectively into the interiors of recesses 83a, which are formed on the inside walls of housing groove 83, as shown in Fig. 3 through Fig. 5, when slider 84 is mounted in housing groove 83, and the pressure exerted by pressure member 88 causes the side end surfaces of projections 88a to be pressed against the inside walls of recesses 83a. Accordingly, slider 84 is capable of movement within housing groove 83 within the range permitted by the restriction represented by the abutment of projections 88a with both end surfaces of the recesses, and tip 85 is free to advance into and retreat from mating groove 81 in accompaniment to movement of slider 84. Furthermore, peaked regions, which engage with grooves formed at projections 88a, protrude from the inner wall surfaces of recesses 83a toward mating groove 81, and, when slider 84 is installed at the rails such that it is pressed inside, the peaked regions that protrude within recesses 83a engage with the grooves formed at projections 88a, causing slider 84 to be retained in this state.In this state, the other overhanging member of the attachment rail is inserted between tip 85 of slider 84 and the base of mating groove 81, and tip 85 engages with the overhanging member such that housing 10 is secured by the attachment rail. Furthermore, in this state, in reaction to the pressing force exerted on the peaked regions by pressure member 88, a force directed so as to cause slider 84 to protrude toward the mating groove 81 side acts at the end surfaces of the mating groove 81 side of projections 88a.

When housing 10 is detached from the attachment rail, with, as described above, slider 84 withdrawn to the outside-surface side of housing 10 through a force sufficient to cause projections 88a to surmount peaked regions 89, projections 88a will be secured in positions between the peaked regions and the side end surfaces outside recesses 83a, and, because tip 85 of slider 84 is sheltered within housing groove 83, the engagement of the attachment rail with the overhanging member will be released, permitting housing 10 to be removed from the attachment rail.

Next, leakage-responsive circuit breaker block 101 contains within housing 10', which is divided into 3 sections by left and right housing members 1 0d and lOe, and central housing member 1 Oc made from a synthetic resin possessing insulating properties, a circuit breaker unit constituted identical to the circuit breaker unit of the aforesaid circuit breaker block 100, and also contains electrical-leakage-unit-like electrical-leakage release mechanism 105, which causes tripping action of the circuit breaker unit based on leak current sensed by zero-phase current transformer CT, and also contains shorted paths for simplification of the wiring within the distribution panel. Furthermore, slider 84, with the same constitution as at housing 10, is installed in housing 10'.

Central housing member 1 0c contains, between the member side surface and housing member 1 Od, a circuit breaker unit constituted identical to the aforesaid circuit breaker block 100 (in the figures, parts possessing identical operation and constitution are labeled with the same numbers and symbols as the parts at circuit breaker block 100, and their description is omitted). This circuit breaker unit and the circuit breaker unit of circuit breaker block 100 are made such that they carry out ganged operation by virtue of ganging plate 106.

In other words, ganging plate 106 is installed to reside within the cavity formed between housing member 1 0d and housing member 10a when blocks 100 and 101 are joined. Shaft hole 106a, provided at the lower end of a vertical member, is mated, so as to allow free rotation, with shafts 107 provided at the outside surface of housing member 1 Od and at the outside surface of housing member 1 Oa. Next, L-shaped cross-section projections 106b, protruding from either side of the central region of the vertical member, are inserted from window holes 108 opened in the outside surface of housing member 1 Od and in the outside surface of housing member 1 Oa through and into housings 10 and 10' so as to allow free movement.Corniform cross-section projections 106c, protruding from either side of the tip of the lateral member, are inserted from guide holes 109 opened in the outside surface of housing member 1 0d and in the outside surface of housing member 1 0a at locations farther above window holes 108 through and into housings 10 and 10' so as to allow free movement. Tips of projections 106b, inserted through and into housings 10 and 10', are inserted between base member 44a and vertical regions of L-shaped members 44g, which protrude from both sides of the lower ends of trip plates 44 of the respective circuit breaker units. Projections 1 06c are arranged at positions opposing engaging plate 46a of latch plate 46, such that movement of latch plate 46 causes them to be pressed upon from engaging plate 46a.

The head of actuation handle 41 of circuit breaker block 100 and the head of actuation handle 41 of electrical leakage circuit breaker block 101 are coupled together through mated attachment of C-shaped cross-section handle cap 99, so as to permit handling as a single actuation handle.

Electrical leakage release mechanism 105 comprises, as shown in Fig. 4 and Fig. 5, tripping electromagnet 111, which drives plunger 110, and ganging lever 112, which converts the rectilinear motion of plunger 110 into rotary motion, and which, as a result of this rotary motion, causes tripping action of drive mechanisms 40 of adjacent circuit breaker units. Tripping electromagnet 111 is supplied with its energizing current via a switching element such as a thyristor of electrical leakage sensing circuit 113 shown in Fig. 8. Electrical leakage sensing circuit 113 is a circuit that amplifies the secondary output of zero-phase current transformer CT, and when that amplified output exceeds a certain level, turns ON the aforesaid switching element thus driving tripping electromagnet 111.The power supply path is connected to power-supply-side connection terminals 20a and 20b of circuit breaker block 100 and electrical leakage circuit breaker block 101.

This tripping electromagnet 111 comprises energizing coil 11 lea and C-shaped yoke 11 1b, both side members of which straddle this energizing coil 111 a, is housed within cavity 114 provided at opposing inside surfaces of housing member 1 0e and central housing member 1 Oc, and is secured as a consequence of being sandwiched between housing member 1 0e and central housing member l Oc. Plunger 111 made from magnetic material is inserted, so as to extend and retract freely, within the central hole of energizing coil 111 a by way of an intervening hole formed at one side member of yoke 111 b.Further, bearing members 111 d and 111 e, which protrude in the direction of protrusion of plunger 110, are provided on upper and lower ends of one side member of yoke 11 lb at the extension/retraction side of plunger 110. Cylindrical region 112a, formed as an integral part on one side surface of main body 11 2b of ganging lever 112, is arranged between these bearing members 11 id and 11 le. Pivot pin 116, which passes through shaft hole 115 of top bearing member 111d from above, is inserted through this cylindrical region 11 2a, while the bottom of pivot pin 116 is inserted within bottom bearing member 111 e, supporting ganging lever 112 such that it can rotate freely.

Ganging lever 112 is provided at main body 112b with throughhole 112c, through which the aforesaid plunger 110 passes. As a result of insertion of narrow-neck region 1 Oa of plunger 110 from the side surface of main body 1 12b into through-hole 112c via slit 1 12d which communicates with through-hole 112c, main body 112b is made to reside between wide-neck region 1 10a and head 1 l Oc of plunger 110, and when plunger 110 is driven by tripping electromagnet 111, rotation about pivot pin 116 occurs in ganged fashion to the rectilinear movement of plunger 110.

Arm member 112d protrudes outward from the upper side surface of cylindrical region 112a. As shown in Fig. 12, the tip region of this arm member 11 2d protrudes from window hole 117, formed at central housing member lOc, toward the circuit breaker housing cavity side between central housing member 1 0c and housing member 1 Od.

Thrust region 1 12f, formed at the tip of arm member 1 12d, opposes first thrust member 44b of trip plate 44 in the tripping direction, and in ganged fashion with the rotation of ganging lever 112, thrust region 11 2f is capable of pressing on and driving first thrust member 44b in the same manner as thermal release mechanism 60.

Projection 11 2g for latching with the electrical leakage indication mechanism protrudes from the outside surface of protruding region 112f, which protrudes above the upper surface of main body 1 12b of ganging lever 112, which is capable of ganged driving of the electrical leakage indication mechanism and tripping action. Coil spring 131 is compressed between this projection 112g and, as shown in Fig. 10, spring seat 130 provided on the inner wall surface of housing member 10e. Coil spring 131 energizes ganging lever 112 so as to cause the aforesaid thrust region 11 2f to separate from first thrust member 44b of trip plate 44.

The electrical leakage indication mechanism comprises indicator 121, wherein shaft 120 which protrudes integrally from the inside side surface near the top of housing member 10e is inserted within shaft hole 121a, provided at one end, so as to rotate freely, and torsion spring 125 which energizes indicator 121. Indicator 121 is provided integrally at the other end with indicating member 121 b, which has a circular-arc cross-section, and is sickle-shaped as viewed from the side. The surface of indicating member 121 b is visible through rectangular-shaped indicator window 124, opened on the upper surface of housing 10' when housing member 10e and central housing member 1 0c butt together.The colors and text on the surface of indicating member 121b visible from indicator window 124 can be changed in accompaniment to rotation of indicator 121, and whether or not tripping action caused by electrical leakage is in effect can be represented by virtue of the colors and text on the surface of indicating member 12 lib visible from this indicator window 124. Further, indicator 121 is provided integrally at one end with latching body 121 c, which as shown in Fig. 10 rides up on and is latched by ganging lever 112, formed on a step 1 12h at the upper surface of projection 1 12g of the aforesaid ganging lever 112.

Shaft 120 is inserted through torsion spring 125 such that the central annular region 125a of the latter is positioned between indicator 121 and housing member 10e, whereby one end of torsion spring 125 engages with the surface of indicator 121 in the clockwise direction in Fig. 10, while the other end engages with the surface of projection 132 provided on the inside surface of housing member 1 0c in the counterclockwise direction. With latching body 121c latched by step 11 2h of projection 11 2f of ganging lever 112 as described above, indicator 121 will be energized by a counterclockwise force from one end of torsion spring 125.If the latch is released while in this state, then indicator 121, bearing the force exerted by torsion spring 125, will rotate counterclockwise and arrive at the state shown in Fig. 14.

Depending on whether the latch is in the latched or the unlatched state, the device is in a no-leakage state or a leakage-action state as indicated by the colors or text on the indicating member 121b surface visible from indicator window 124 opened on the upper surface of housing 10'.

In order to test the operation of ordinary electrical leakage release mechanism 105, the leakage-responsive circuit breaker is provided with a test circuit for simulating flow of electrical leak current.

The test circuit of the embodiment, as shown in Fig. 8, comprises circuit breaker block 100, an electric path connected at both ends to power-supply-side connection terminals 20a and 20b of leakageresponsive circuit breaker block 101 and passed through the hole of the toroidal core of zero-phase current transformer CT, test switch SW2 inserted in this electric path, and test circuit interrupt switch SW1, wherein opening and closing of interrupt switch SWl is ganged to the indicated action of the aforesaid electrical leakage indication mechanism.

Here, both switches SW1 and SW2 possess movable contact members 160, and 1602, formed through the use of common movable contact plate 160. Movable contact plate 160 is formed such that it is bent into roughly an "L" shape, and vertical member 1 60a is mated and secured between it and inner protruding wall 150a, which is formed integrally at the inside surface of housing member 1 0e so as to be parallel in the neighborhood of vertical protruding wall 150d provided at the outer wall of housing member 10e of power-supply-side connection terminal 20a, as shown in Fig. 10.This mating and securing causes projection 140a, which protrudes from the inside surface of vertical protruding wall l50d, and projections 140b and 140b, the tips of which are located somewhat more toward the wall than the tip position of projection 140a, to either side of projection 140a, to protrude from the inner protruding wall 1 50a side. Pressing and flexing by these projections 140a, 140b, and 140b from directions mutually opposing either side of vertical member 160a, retains them, and elastically joins small projection member 160c, which protrudes from the lower end of vertical member 160a so as to be parallel to horizontal member 160b, to the lower end of the aforesaid inner protruding wall 150a.

Horizontal member 160b, as shown in Fig. 6, is split into a bifurcated shape by a V-shaped notched groove extending from base to tip along the center line, and these split members make up the aforesaid movable contact members 160l and 1602, which increase in width from the free ends to the base. In addition, base of horizontal member 1 60b is joined at one end to the top of inner protruding wall 1 50a, and is pushed up by projection 140c protruding from the top surface of inner protruding wall 1 SOb, which is formed integrally on the inside surface of housing member 10e, the tips of both movable contact members 160, and 1602 being directed at an incline. The upper surfaces of movable contact members 160, and 1602 are elastically joined to the lower R surface of projection 150e, which protrudes from the inside surface of housing member 10e above inner protruding wall 150b, and are restrained such that they bounce up no higher than that.

The pair of fixed contact plates 170l and 1702 corresponding to respective movable contact members 160, and 1602, as shown in Fig. 4, is secured by press-fitting, through the use of projections 170a, the respective base members into the two slit grooves 141 formed in the vertical direction at the sides of inner protruding walls 1 50f, provided at the inside surfaces of housing member 1 0e and central housing member 1 Oc. The pair protrudes from the member side (at mutually opposite sides) at the upper surface of each of the base members, which are open-mounted on the upper surface sides of inner protruding walls 150f, in directions facing fixed-contact contacting projections 171, and 1712 such that they are parallel with inner protruding wall 150b.The tips of these contacting projections 1711 and 1712 abut the upper surfaces of inner protruding walls 150f, and their base ends are formed so as to be positioned somewhat above the upper surface of inner protruding walls 150f. The gap formed between them and the upper surfaces of inner protruding walls 150b provides compliance when movable contact members 160l and 1602 make contact.

Here, test button 180, for pressing and driving movable contact member 1602 of test switch SW2, is made up of a roughly C-shaped molded synthetic resin part, is housed so as to move freely up and down within test button housing 181 which is formed within housing member 1 0e above the aforesaid inner protruding wall l 50a of housing member 10e, is constantly energized upward by coil spring 182 which is compressed between the central member and the base of test button housing 181, and causes head 180a, formed at the upper surface of the central member, to protrude outward from exposing window 183 which is formed at upper surface of housing member 1 0e corresponding to test button housing 181.One side member of test button 180 is formed longer than the other side member, the tip thereof protruding downward from notch 181 a formed in the base of test button housing 181. In addition, extending in a diagonal direction from that tip is driving member 180b, and at the tip thereof, downward thrust region 1 80c opposes movable contact member 1602 near its center.

Accordingly, pressing head 1 80a of test button 180 down against the spring elasticity of coil spring 182 causes thrust region 1 80c of driving member 180b to press on movable contact member 160,.

Next, movable contact member 1602, its free end being pushed down as it pivots about its base, which is pushed upward by projection 140c, presses elastically against fixed-contact contacting projection 1712 of corresponding fixed contact plate 1702 to achieve the ON state.

Movable contact member 160 of interrupt switch SW1 is driven by operating member 190, which is ganged to operation of the aforesaid electrical leakage indication mechanism. Operating member 190 pivots so as to rotate freely, wherein shaft 120 which passes through indicator 121 is inserted through shaft hole l90a provided at one end. Engaging projection 190b which abuts the surface of indicator 121 in the counterclockwise direction protrudes from the side surface of the other end at the indicator 121 side.Projection 190c, which is inserted within groove formed on the side surface of actuation handle 41 of adjacent circuit breaker units, protrudes at the other side surface, projecting from opening in the side surface of housing member l Oc. Accordingly, the constitution moves in conjunction with actuation handle 41.

Power-supply connection terminals 20a and load-side connection terminals 20b are provided at both ends of housing 10 of circuit breaker block 100 and the housing unit comprising housing member 1 0c and central housing member 1 Oc. Terminal housing regions 24a and 24b, which respectively house similarly constructed connection terminal 20a' and connection terminal 20b' are also provided at both ends of the housing unit comprising housing member 1 0e and central housing member I Oc. The lower ends of terminal plate 21 a and terminal plate 21 b of both this connection terminal 20a' and this connection terminal 20b' are connected, as shown in Fig. 10, by shorting line 119, composed of braided wire such that connection terminals 20a', which are lined up at the power-supply-side connectionterminal-20a side, constitute the load-side connection terminals 20b.

Furthermore, recess 102', which constitutes the side end region of the zero-phase current transformer CT housing compartment, comprised of recesses 102 formed in housing members l0a through lOd, is formed below terminal housing chamber 24a, wherein connection terminal 20a' is housed. The side wall of this recess 102' blocks the region at the end of one side of the housing compartment. Cavity 114 communicates with recess 102' so as to permit routing of the leads making up the electrical path of the test circuit, and secondary coil lead 200 of zerophase current transformer CT.

Thus, during assembly of the leakage-responsive circuit breaker of this embodiment, housing member 1 0c of housing 10' of leakageresponsive circuit breaker block 101, with its built-in circuit breaker unit, is butted against the housing-member- 1 Oa side of housing 10 of circuit breaker block 100, with its built-in circuit breaker unit.Then, after provisionally securing at the housing member 1 0e side printed circuit board 118, whereon the various materials for the electrical leakage interruption mechanism and the electrical leakage indication mechanism and the circuit components of electrical leakage sensing circuit 113 are mounted, this housing member 1 0e is butted with and joined to central housing member lOc, and projection 190c of operating member 190, which protrudes from the upper side surface of housing member lOe, is joined with groove of actuation handle 41 of the circuit breaker unit, which protrudes above.

At this time, zero-phase current transformer CT, through which the leads of the test circuit electrical path and braided line 103 connecting fixed contactor 31 and power-supply connection terminals 20a of the circuit breaker units of both blocks 100 and 101 have been inserted, is arranged within recess 102 which is below power-supply connection terminals 20a of housings 10 and 10'. In addition, secondary coil lead 200 of zero-phase current transformer CT is connected to the electrical leakage sensing circuit 113 of printed circuit board 118. Then, cover 201 which is a part molded from synthetic resin and provided with walls in three directions, at the front, base and one side is placed over housing 10 and 10' so as to occlude the housing compartment comprising contiguous recesses 102 and 102'. At this time, the upper edge and rear edge of the side walls of cover 201 are mated with step 203 formed at the outside peripheral rim of recess 102 of housing member lOb, the rear edge of the base wall is mated with steps 204 formed at the lower edge of recesses 102 of housing members 1 Oa through 1 Od, and the peripheral edge of the opening at the recess 102' side of housing member 1 0e is mated with and inserted into recess 102'. Projection 205, formed at the lower rear region of the side walls, is mated to recess 206, provided at the lower end of recess 102 of housing member lOb, and causes assembly hole 12, opened in this recess 206, to communicate with assembly hole 12' provided at projection 205.

From this state, rivet 11 is inserted through assembly hole 12' of cover 20, and assembly holes 12 of housing members 1 0a through 1 Oe, which communicate with each other, and as a result ofjoining and securing cover 201 and housing members 1 0a through 1 owe, the electrical leakage unit integrally composed of circuit breaker block 100, electrical leakage circuit breaker block 101, and cover 201 is completed.

Next, as shown in Fig. 7, when arranged so as to employ branch-line breakers 303... and DIN rail 307 for trunk-line circuit breakers within distribution panel 300, load-side connection terminals 20b', wherein shorting line 119 is connected, are connected to load-side connection terminals 20b at the adjacent-circuit-breaker-unit side with C-shaped coupling bar 207. Connection terminals 20a', connected to connection terminals 20b' by shorting line 119 are connected to terminal mechanism 301, arranged at distribution panel 300 at the power-supply-side connection-terminal-20a side, with lead. In this way, load connection between this terminal mechanism 301 and the powersupply-side connection terminals 304a of each of branch-line breakers 303... is accomplished.In addition, load-side connection terminals 20b of circuit breaker block 100 are connected with load-side connection terminals 20b of each of branch-line breakers 303 by coupling bar 305.

Further, trunk-line leads 306 are respectively connected to powersupply-side connection terminals 20a of circuit breaker block 100 and leakage-responsive circuit breaker block 101.

Next, circuit breaker operation will be described. Fig. 9 shows the circuit breaker in the "on" state (contacts closed), operation member 41 a of actuation handle 41 thrown around handle shaft 42 to the right.

At this time, trip plate 44 is energized counterclockwise (as viewed in Fig. 9) around shaft pin 47 by the spring force of handle return spring 43, thus holding first push pressure member 44b in contact with adjustment screw 62 in bimetal [bar] 61. Moreover, the spring force of contact spring 34 is being applied via movable contactor 33 and contact link 48 to latch plate 46, and, because the distance between leg 48a of contact link 48 and shaft tabs 41d on actuation handle 41 is regulated by handle link 45, latch plate 46 receives the spring force of contact pressure spring 34 such as to energize it in the counterclockwise direction with handle shaft 42 as the center of rotation. Accordingly, stop plate 46a of latch plate 46 is engaged in hook notch 44e in arm 44d of trip plate 44.In other words, the state shown in Fig. 9 is maintained because although latch plate 46 is trying to rotate to the right, it is being prevented from doing so by latch plate 46. In this state, latch plate 46 is held in position by shaft handle 42 and trip plate 44, and handle link 45 and contact link 48 are also fixed in their proper positions. As a result, movable contactor 33 is energized in the counterclockwise direction, centered around leg member 48b of contact link 48, by the spring force of contact pressure spring 34. In other words, movable contact 32 is contacting fixed contactor 31 with a pressure corresponding to the spring force of contact pressure spring 34.

In this state, the position relationship of stopper 36, provided on the inside surface of housing 10, is set so that it will not touch spring receiver member 33b of movable contactor 33.

At this point, as shown in Fig. 10, indicator 121 is in a state wherein latching body 121 c is engaged with step 11 2h of projection 11 2g of ganging lever 112, and indicating member 121 b indicates, through indicator window 124, a no-leakage state. At this time, torsion spring 125 is pushed apart.

Operating member 190 rotates in correspondence to rotation of actuation handle 41, as shown in the figures, and pushes movable contact member 1601 down through thrust projection 190d provided at its lower end, causing the free ends of movable contact member 1601 to come in contact with contacting projections 171 and interrupt switch SW1 to be in the ON state.

Throwing the actuation region 41a of actuation handle 41 counterclockwise about handle shaft 42 as shown in Fig. 11, causes open/close contacts 30 to go into the open-contacts state. In effect, rotation of actuation handle 41 counterclockwise about handle shaft 42 causes the upper end of handle link 45 to move right, so as to attempt to lift foot member 48a of contactor link 48 upward. When the positions of shaft projections 41d move to the right of a straight line connecting handle shaft 42 and foot member 48a, the restoring force exerted by contact spring 34, through movable contactor 33 and contactor link 48 on handle link 45 acts to rotate actuation handle 41 even further counterclockwise, causing foot member 48b of contactor link 48 to move left along guide groove 16.As a result of foot member 48b of contactor link 48 moving left in this fashion, spring holder 33b of movable contactor 33 butts against stopper 36, provided at the inside peripheral surface of housing 10, because of the restoring force from contact spring 34. Because the restoring force of contact spring 34 acts at a location below the lower end of stopper 36, movable contactor 33 is energized clockwise, causing movable contact 32 to separate from fixed contactor 31. With open/close contacts 30 in the open-contacts state, latch plate 46 is restricted by handle link 45 and foot member 48a of contactor link 48, and rotates counterclockwise about handle shaft 42, causing it to disengage from trip plate 44.

At this point, indicator 121 is in a state wherein latching body 121 c is engaged with step 1 12h of projection 1 12g of ganging lever 112, as shown in Fig. 12, and indicating member 121b, through indicator window 124, is indicating a no-leakage state. At this time, torsion spring 125 is pushed apart.

Further, operating member 190 rotates in correspondence to rotation of actuation handle 41, as shown in the figures, removing the downward pushing of movable contact member 160, by means of thrust projection l90c, provided at the lower end, and causing the free ends of movable contact member 160, to disengage from contacting projections 171l, thereby putting interrupt switch SW1 in the OFF state. In short, from this state, the test circuit will not operate despite test switch SW2 entering the ON state.

If, however, in the closed contact state shown in Fig. 9, an overload causes excessive current to flow in bimetal [bar] 61, causing bimetal [bar] 61 to bend, adjustment screw 62, which is threaded into bimetal [bar] 61, will be pressed against first push pressure member 44b of trip plate 44, or if excessive current flows in coil 51 due to a short, etc., on the load side, plunger 54 will be drawn into fixed core 55, pushing push pressure pin 57, which is attached to the plunger, against second push pressure member 44c of trip plate 44. In either case, trip plate 44 will rotate clockwise with shaft pin 47 as its center of rotation.

Rotation of trip plate 44 clockwise disengages it from latch plate 46, and since in the closed contact state, latch plate 46 receives the spring force of contact pressure spring 34, which energizes it in the clockwise direction around handle shaft 42, the lower end of latch plate 46 moves to the left. In other words, leg 48b of contact link 48, which, in the closed contact state, was the center of rotation of movable contactor 33, moves to the left along guide channel 16. Therefore, as in the open contact state, movable contactor 33 is pressed against stopper 36 by the spring force of contact spring 34, movable contact 32 is separated from fixed contactor 31, and the circuit breaker assumes the open contact state. Hence, if excessive current flows in the main electrical path, trip plate 44 rotates, disengaging it from latch plate 46.This releases the energy being stored by latch plate 46, thereby performing the so-called tripping operation, to open the breaker contacts. In accompaniment to this tripping action, rotation of engagement plate 46a of latch plate 46 causes ganging plate 106, its projections 106c being pushed upon, to rotate counterclockwise as shown in the figures. As a result of this counterclockwise rotation, projections 106b, overlooking the adjacent circuit breaker units, push on L-shaped members 44g of trip plates 44 of said circuit breaker units, and rotate trip plates 44 clockwise, i.e., in the tripping direction. Accordingly, said circuit breaker units also accomplish tripping action in ganged fashion with the aforesaid tripping action, and cause open/close contacts 30 to open.

Following tripping action of both of these circuit breaker units, handle return spring 43 causes actuation handle 41 to return to the position of the OFF state, and in addition, to cause the states of the circuit breaker units to return to the OFF state.

Now, flow of a leak current in the electric path of the circuit breaker unit of either circuit breaker block 100 or leakage-responsive circuit breaker block 101 in Fig. 9 causes an unbalanced current to flow at zero-phase current transformer CT, generating secondary output. In response to this secondary output, tripping electromagnet 111 of electrical leakage release mechanism 105 is energized. This causes plunger 110 to be driven and to rotate ganging lever 112 about pivot pin 116. As a result of this rotation, latching body 121 c of indicator 121 is freed from step 1 12h of projection 1 12g of ganging lever 112, and indicator 121 rotates counterclockwise in Fig. 9 from the restoring force of torsion spring 125, changing the indication of indicating member 121b through indicator window 124 to indicate leakage action, as shown in Fig. 14.

Now, rotation of ganging bar 112 causes thrust region 11 2f at the tip of arm member 11 2e of ganging bar 112 to push and move in the tripping direction first thrust members 44b of trip plates 44 of adjacent circuit breaker units, causing tripping action of the circuit breaker units in the same manner as in the aforesaid tripping action, as shown in Fig.

13, such that open/close contacts 30 open. This tripping action, in addition, also causes tripping action of the circuit breaker unit of circuit breaker block 100 through ganging plate 106 so that open/close contacts 30 open.

Following removal of the aforesaid cause of electrical leakage, resetting of the leakage-action indication is carried out as follows.

First, rotation of actuation handle 41 from the OFF state to the ON state causes operating member 19 to rotate clockwise in ganged fashion with this rotation. During this rotation, projection l90b of operating member 19 engages with indicator 121, causing indicator 121 to rotate clockwise against the restoring force of torsion spring 125. With the elimination of the driving of plunger 110 caused by tripping electromagnet 1 111, the restoring force of coil spring 131 causes ganging bar 112 to return to its original state, and rotation of indicator 121 causes latching body 121c to ride up on step 1 12h of projection 112g, and to become latched. In short, indicator 121 returns to its original state, and the indication carried out by indicating member 121b through indicator window 124 becomes no-leakage.

Now at open/close contacts 30 in Fig. 9, pushing head 180a of test button 180 causes the free ends of movable contact member 1602 to be pushed down by thrust region 180c of test button 180, and to come in contact with contacting projection 1712 of fixed contact plate 1702, thus turning test switch SW2 into the ON state and causing current to flow in the test circuit by way of interrupt switch SW1, thereby permitting simulated flow of an unbalanced current at the primary side of zero-phase current transformer CT. In other words, it is possible to produce the same state as actually occurs during electrical leakage, allowing tripping action to be caused at the circuit breaker unit.

Here, because power supply to the test circuit and electrical leakage sensing circuit 113 is accomplished from power-supply-side connection terminals 20a, continual pressing of test button 180 causes current to continue to flow in the test circuit, and energizing current to continue to flow in coil 11 la of tripping electromagnet 111. But since in this embodiment emergence of tripping action results in rotation of operating member 190 to the OFF state in ganged fashion with the return of actuation handle 41 to the OFF state and the removal of the downward pushing of movable contact member 160,, the free ends of movable contact member 1601 are disengaged from contacting projection 1712, turning interrupt switch SW1 OFF, and interrupting the current flowing in the test circuit. Accordingly, thereafter current will not flow in the test circuit even if test switch SW2 is turned ON, and terminating the energizing of coil 111 a of tripping electromagnet 111 by electrical leakage sensing circuit 113 prevents burnout damage or the like to coil 11 la.

Claims

CLAIMS:

1. A leakage-responsive circuit breaker comprising: a drive mechanism linked to a handle for opening and closing a contact and linked to release means for opening said contact upon actuation of said release means; a plurality of movable contactors electrically connected to movable-side terminals and linked to said drive mechanism so as to be driven thereby to open and close said contact; a plurality of fixed contactors arranged in engageable relation to said movable contactors and electrically connected to fixed-side terminals; and a zero-phase current transformer disposed around current paths between said fixed-side terminals and movable-side terminals and providing a leakage signal for actuating said release means of said drive mechanism; wherein said zero-phase current transformer is disposed in the current paths between said fixed contactors and said fixed-side terminals.

2. The leakage-responsive circuit breaker as set forth in claim 1, wherein a housing is provided to accommodate said drive mechanism, said movable contactors, said fixed contactors, and said zero-phase current transformer, said housing being provided at its one end with said fixed-side terminals and at the other end with said movable-side terminals, and said zero-phase current transformer being disposed adjacent to a mounting surface of said housing and adjacent to said fixed-side terminals.

3. The leakage-responsive circuit breaker as set forth in claim 2, wherein said housing is provided in the mounting surface adjacent to said fixed-side terminals with a space for accommodating said zerophase current transformer, said space being closed by a cover fitted from the mounting surface of said housing.

4. The leakage-responsive circuit breaker as set forth in claim 2 or 3, wherein a leakage-responsive release mechanism is provided to include an electromagnet actuating said release means in response to the age signal from the zero-current transformer, said leakage-responsive release mechanism being accommodated within an additional space formed on the side of said housing in combination with an additional housing, said additional space being communicated with said space.

5. The leakage-responsive circuit breaker as set forth in claim 4, wherein said additional housing has means for securing said leakageresponsive release mechanism prior to assembling said additional housing to said housing.

6. The leakage-responsive circuit breaker as set forth in claim 1, wherein said zero-phase current transformer detects a leakage current such as a leak or grounded current, and wherein said breaker including: an interruption mechanism for opening the contact disposed in the current path in response to the output of said zero-phase current transformer; and a test switch in a test circuit for generating a simulative leakage current in said zero-phase current transformer; said test switch being comprised of a pair of fixed contact plates, a movable contact plate having bifurcated free ends opposed respectively to said fixed contact plates and having a fixed end, and a test button disposed in opposite relation to one of said bifurcated free ends so as to make the other bifurcated free end engageable with one of said fixed contact plate, an actuator being provided to oppose said other bifurcated free end of said movable contact plate, said actuator interlocking with said interruption mechanism such that said actuator causes said other bifurcated free end to be disengaged from the corresponding fixed contact plate when said interruption mechanism responds to open the contact.

7. The leakage-responsive circuit breaker as set forth in claim 6, wherein said bifurcated free ends of said movable contact plate is separated by a slit having a slit width wider towards its open end than at a closed end such that said bifurcated free end portions have a tapered width narrower towards the free ends.

8. The leakage-responsive circuit breaker as set forth in claim 6, wherein each of said fixed contact plates has a contact projection projecting on one side of a general plane of said contact plate, said fixed contact plates disposed generally perpendicular to said movable contact plate while opposing said contact projections.

9. The leakage-responsive circuit breaker as set forth in claim 1, including: a circuit interruption unit which allows said handle to make said movable contactor engageable with said fixed contactor and which causes said movable contactor to be disengaged from the fixed contactor upon seeing an abnormal current; and a release unit which is linked to actuate said circuit interruption unit in a direction of opening the contact; wherein said circuit interruption unit and said release unit are accommodate within a housing in a side-by-side relation along one dimension, said housing being provided at opposite ends of the other dimension perpendicular to said one dimension with terminals for connection with external wires, and said terminals on the side of said release unit being shorted.

10. The leakage-responsive circuit breaker as set forth in claim 9, wherein at least two said circuit interruption units are arranged side-byside, said release unit defining a leakage detecting unit for detecting leak current or grounded current flowing through at least two said circuit interruption units and for actuating the said circuit interruption unit.

11. A leakage-responsive circuit breaker substantially as herein before described with reference to the accompanying drawings.

11. The leakage-responsive circuit breaker as set forth in claim 9, wherein a coupling bar is provided to electrically interconnect the terminals of said circuit interruption unit and said release unit.

12. A leakage-responsive circuit breaker comprising at least two terminals and a current transformer in the electrical path between the two terminals, and an open/close action mechanism actuable by an actuation member wherein the open/close action mechanism and a movable contactor contacting one of the terminals are mounted so as to be independent of the current trans former.

13. A leakage-responsive circuit breaker substantially as herein before described with reference to the accompanying drawings.

Amendments to the claims have been filed as follows CLAIMS: 1. A leakage-responsive circuit breaker comprising: a drive mechanism linked to a handle for opening and closing a contact and linked to release means for opening said contact upon actuation of said release means; a plurality of movable contactors electrically connected to movable-side terminals and linked to said drive mechanism so as to be driven thereby to open and close said contact; a plurality of fixed contactors arranged in engageable relation to said movable contactors and electrically connected to fixed-side terminals; and a zero-phase current transformer disposed around current paths between said fixed-side terminals and movable-side terminals and providing a leakage signal for actuating said release means of said drive mechanism; wherein said zero-phase current transformer is disposed in the current paths between said fixed contactors and said fixed-side terminals, and wherein a housing is provided to accommodate said drive mechanism, said movable contactors, said fixed contactors, and said zero-phase current transformer, said housing being provided at its one end with said fixed-side terminals and at the other end with said movable-side terminals, and said zero-phase current transformer being disposed adjacent to a mounting surface of said housing and adjacent to said fixed-side terminals.

2. The leakage-responsive circuit breaker as set forth in claim 1, wherein said housing is provided in the mounting surface adjacent to said fixed-side terminals with a space for accommodating said zero phase current transformer, said space being closed by a cover fitted from the mounting surface of said housing.

3. The leakage-responsive circuit breaker as set forth in claim 1 or 2, wherein a leakage-responsive release mechanism is provided to include an electromagnet actuating said release means in response to the age signal from the zero-current transformer, said leakage-responsive release mechanism being accommodated within an additional space formed on the side of said housing in combination with an additional housing, said additional space being communicated with said space.

4. The leakage-responsive circuit breaker as set forth in claim 3, wherein said additional housing has means for securing said leakage responsive release mechanism prior to assembling said additional housing to said housing.

5. The leakage-responsive circuit breaker as set forth in claim 1, wherein said zero-phase current transformer detects a leakage current such as a leak or grounded current, and wherein said breaker including: an interruption mechanism for opening the contact disposed in the current path in response to the output of said zero-phase current transformer; and a test switch in a test circuit for generating a simulative leakage current in said zero-phase current transformer; said test switch being comprised of a pair of fixed contact plates, a movable contact plate having bifurcated free ends opposed respectively to said fixed contact plates and having a fixed end, and a test button disposed in opposite relation to one of said bifurcated free ends so as to make the other bifurcated free end engageable with one of said fixed contact plate, an actuator being provided to oppose said other bifurcated free end of said movable contact plate, said actuator interlocking with said interruption mechanism such that said actuator causes said other bifurcated free end to be disengaged from the corresponding fixed contact plate when said interruption mechanism responds to open the contact.

6. The leakage-responsive circuit breaker as set forth in claim 5, wherein said bifurcated free ends of said movable contact plate is separated by a slit having a slit width wider towards its open end than at a closed end such that said bifurcated free end portions have a tapered width narrower towards the free ends.

7. The leakage-responsive circuit breaker as set forth in claim 5, wherein each of said fixed contact plates has a contact projection projecting on one side of a general plane of said contact plate, said fixed contact plates disposed generally perpendicular to said movable contact plate while opposing said contact projections.

8. The leakage-responsive circuit breaker as set forth in claim 1, including: a circuit interruption unit which allows said handle to make said movable contactor engageable with said fixed contactor and which causes said movable contactor to be disengaged from the fixed contactor upon seeing an abnormal current; and a release unit which is linked to actuate said circuit interruption unit in a direction of opening the contact; wherein said circuit interruption unit and said release unit are accommodate within a housing in a side-by-side relation along one dimension, said housing being provided at opposite ends of the other dimension perpendicular to said one dimension with terminals for connection with external wires, and said terminals on the side of said release unit being shorted.

9 .The leakage-responsive circuit breaker as set forth in claim 8, wherein at least two said circuit interruption units are arranged side-by side, said release unit defining a leakage detecting unit for detecting leak current or grounded current flowing through at least two said circuit interruption units and for actuating the said circuit interruption unit.

10. The leakage-responsive circuit breaker as set forth in claim 8, wherein a coupling bar is provided to electrically interconnect the terminals of said circuit interruption unit and said release unit.