JPH038026Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[1] Technical Field The present invention connects the power fuses connected to each phase between the busbar connected to the three-phase trunk line on the power supply side and multiple pairs of three-phase branch lines on the load side. A three-phase fixed electrode connected to the bus bar and the three-phase branch line is arranged on the top of the frame stored in the storage box so that the three-phase fixed electrode can be easily pulled out in a three-pole interlocking manner. Power fuses for each phase are housed in a cover, and multiple pairs of three-phase movable electrodes attached to a base frame for each three phases are removably inserted into the upper part of the three-phase fixed electrode, and the three-phase movable electrode The present invention relates to a low-pressure branching device that is pulled upward using a detachable operating handle. [2] Background Art For example, as a conventional low-pressure branching device, there is one shown in FIG.
A stay 3 is attached between the inner wall of the lid 2 and the inside of the lid 2 to maintain the upright state of the lid 2, a frame 4 is fixed to the inside of the lid 2, and a three-phase power supply side is attached to the frame 4. A plurality of pairs of three-phase branch lines 7 on the load side are respectively connected to the main line 5 and the three-phase main line 5 via power fuses 6 attached to the frame 4.
It is composed of. In the above configuration, normally, the lid 2 is closed and the branching device main body is stored in the storage box 1.
Electric power supplied from the power supply side to the three-phase main line 5 is branched at each three-phase branch line 7 via a power fuse 6 connected to each phase, and is then supplied to the load side. If a short circuit accident occurs on the load side and overcurrent flows through the three-phase branch line 7, the power fuses 6 of each phase will melt and the three-phase branch line 7 where the accident occurred will be cut off.
The main line 5 and system equipment are protected from overcurrent. When inspecting or replacing the connection state of the branching device or the power fuse, the work can be easily done on the ground by raising and opening the lid 2 and protruding the branching device body above the ground. However, in the conventional low voltage branch device, the power fuses 6 for each phase are each independently attached to the frame 4, so the blown power fuses 6
In order to replace the power fuse 6, it is necessary to use a removal tool or the like to pull out one fuse for each phase and replace it with a new one, which not only takes time and effort, but also causes an open phase when the power fuse 6 is pulled out. In addition, since the power fuse 6 is installed horizontally, the installation area becomes large and this is unfavorable in view of the fuse's fusing characteristics. The fusing characteristics of the fuse are as follows. For example, as shown in FIG. 1b, a fuse element 6 such as a silver plate having a diameter d of about 30 to 50 mm
a, 6b, and 6c (the fuse tube is not shown) are horizontally arranged with a distance l that is approximately the same as the diameter d, and 100% rated current is applied to each fuse element.
The surface temperatures of surfaces A, B, C, D, E, and F of each of the fuse elements 6a, 6b, and 6c, and the surface temperature of the fuse tube provided on the outer periphery thereof were investigated. The table below shows the results.

[Table] From this table, the upper D of fuse element 6b
fuse element 6, which has the highest temperature and is located in the lower layer.
It can be seen that the temperature at the lower side A of a is the lowest.
That is, the fuse element 6b receives the radiant heat from the fuse element 6a and the fuse element 6b, and the fuse element 6c receives the radiant heat from the fuse element 6b. The problem here is that the temperature of the surface D of the fuse element 6b has reached 200°C. When a silver plate is used as a fuse element, its fusing temperature is
Although the temperature is 1100° C. or higher, the thermal deterioration temperature is about 200° C., so there is a risk that the fusing characteristics of the fuse element 6b will fluctuate. [3] Purpose and structure of the invention The present invention has been made in view of the above, and improves the workability of replacing fuses, reduces the installation area of fuses, improves fuse blowing characteristics, and facilitates confirmation of fuse blowouts. Therefore, the following configuration is adopted. In other words, it has a frame housed in a storage box, and a three-phase main line on the power supply side and multiple sets of three-phase branch lines on the load side connected to power fuses are interconnected via a busbar attached to the frame. fixed electrodes for the three-phase main line and the three-phase branch line connected to the switching ends of the three-phase main line, the three-phase branch line, and the bus bar, respectively; a pair of movable electrodes for the three-phase main line and the three-phase branch line that are attached to a base frame supported by the frame for each circuit of the main line and the three-phase branch line, and that are connected to and released from the fixed electrode; and a power fuse connected between the pair of movable electrodes for the three-phase branch line, the power fuse having a predetermined length connected to one of the pair of movable electrodes. vertically supported by being spanned between a first fuse mounting plate on the side of the upper end of the vertical member and a second fuse mounting plate connected to the other electrode of the pair of movable electrodes; The movable electrode is watertightly protected by a vertically long transparent cap that allows the whole to be seen through, and the movable electrode is raised and lowered in units of each circuit by an operation handle that removably engages with the base frame. To provide a low voltage branching device having a structure in which the power fuse is opened and the power fuse is connected and disconnected with the transparent cap removed in the open state. [4] Embodiment The underground low-pressure branching device according to the present invention will be described in detail below. Figures 2a, b, and c show an embodiment of the present invention,
A storage box 11 which is provided below the ground surface and has an upper end opening to which a waterproof gasket 10 is attached; a lid 12 which is attached to the upper end opening of the storage box 11 so that it can be opened and closed; A pair of guide rails 14 having a substantially U-shaped cross section are fixed to the guide rails 14 with bolts 13 or the like.
and a removable grounded box-shaped frame 16 having a roll 15 rotating within the guide rail 14 and slidable substantially vertically along the guide rail 14.
a pair of handles 17 attached to the upper part of the frame 16 for pulling out the frame 16 from inside the storage box 11 to the ground; a cable support fitting 18 fixed to the lower end of the frame 16 in a substantially horizontal direction; The cable support fitting 1 is introduced into the storage chamber 11.
8 _, and the U, V, W, and N phases are arranged in the vertical direction in _{FIG .
4} , 20 ₅ , 20 ₆ , and a three-phase, four-wire bus bar 21 disposed approximately horizontally in the approximate center of the frame 16;
An insulating main line terminal cover 22 ₁ that covers the terminals connected to the terminals of each main line 20 ₁ , 20 ₂ ,
22 ₂ , insulating branch wire terminal covers 22 ₃ , 22 ₄ , 22 ₅ , 22 ₆ that respectively cover the terminals connected to the terminals of the branch wires _{20 3} to 20 ₆ , and busbars fixed to the frame 16 21 and the terminals in each main line terminal cover 22 ₁ , 22 ₂ , a three-phase main line fixed electrode 23 having a pair of contact members respectively connected to
₁ , 23 ₂ and a pair of contact members fixed to the frame 16 and connected to the bus bar 21 and the terminals in the terminal covers _{22 3} to 22 ₆ for each branch line. ,23 ₄ ,23 ₅ ,23 ₆
and a three-phase main line movable electrode 2 which has a pair of contact members that are inserted into and removed from the pair of contact members of each of the fixed electrodes 23 ₁ to 23 ₆ , and these are attached to a base frame for each three phases.
4 ₁ , 24 ₂ and branch line movable electrodes 24 ₃ , 24 ₄ ,
24 ₅ , 24 ₆ , and the connecting member, power fuse _, etc. located at the top of the frame ₁₆ and connected between the contact members of each movable electrode 24 ₁ to 24 ₆ . An inverted cup-shaped cover 25 ₁ made of transparent resin or the like is attached to the upper part in a substantially vertical direction,
25 ₂ , 25 ₃ , 25 ₄ , 25 ₅ , 25 ₆ , a protrusion member 26 for pulling out the movable electrodes protruding from both ends of the base frame of each of the movable electrodes 24 ₁ to 24 ₆ in a substantially vertical direction, and each protrusion. A fulcrum member 27 for pulling out the movable electrode protruding substantially vertically from the upper end of the frame 16 corresponding to the member 26, and a cover provided at the upper end of the frame 16 corresponding to each cover 25 ₁ to 25 ₆ 25 ₁
~25 Card holder 2 where you write the placement number etc. of ₆
It consists of 8. The circuit configuration of the three-phase, four-wire, underground low-voltage branch device constructed in this way is as shown in the single-line wiring diagrams in Figure 3 a and b, and corresponds to the U, V, and W phases in Figure a. The connecting member 2
Main line 20 ₁ on the power supply side connected by 9,29 ₁ ,
20 ₂ and power fuse 30, 30, 30, 30
The branch lines 20 ₃ to 20 ₆ on the load side connected to each other are mutually connected via the bus 21, and the main lines 20 ₁ and 20 ₂ and the bus 21 are connected to the connecting members 29 and 2.
9 are connected to fixed electrodes 23 ₁ , 23 ₂ and movable electrodes 24 ₁ , 24 ₂ which can be inserted and removed, respectively, and
The branch lines 20 ₃ - 20 ₆ and the bus bar 21 and the power fuses 30, 30, 30, 30 are connected by removable fixed electrodes 23 ₃ - 23 ₆ and movable electrodes 24 ₃ - 24 ₆ , respectively. In addition, for the N phase in Figure b, the N phase main lines 20 ₁ , 20 ₂ and the N phase branch line 2
0 ₃ to 20 ₆ are connected to each other by each fixed electrode 32. FIG. 4 is a partially enlarged view of the left side of FIG. 2b, showing the fixed electrodes 23 ₁ to 23 ₆ and the movable electrodes 24 ₁ to
24 ₆ etc. are shown in detail. In addition to the connection state between the first main line 20 ₁ and the bus bar 21, FIG. 4 also shows the connection state between the second main line 20 ₂ and the branch lines 20 ₃ to 20 ₆ and the bus bar 21 for convenience of structural explanation. They are also depicted together. As shown in FIG. 4, branch wire fixed electrodes 23 ₃ to 23 ₆ are fixed to the frame 16.
each contact member 23a connected to the bus bar 21,
Each branch line 20 ₃ to 2 is connected via each terminal 22 a covered with a branch line terminal cover 22 ₃ to 22 ₆ .
0 ₆ and an insulating member 23c covering the outer periphery of each contact member 23a, 23b. In addition, fixed electrode 2 for each branch line
The movable electrodes 24 ₃ to 24 ₆ for branch lines, _which are removably inserted into the respective fixed electrodes _{23 3 to} 23 ₆
A pair of contact members 24a, 24b inserted into and removed from the pair of contact members 23a, 23b, respectively, and each insulating member 2 covering the outer periphery of the contact members 24a, 24b.
4c, a substantially L-shaped connection fitting 24d fixed to the top of each contact member 24a, and a plate-shaped connection fitting 24e fixed to the top of each contact member 24b. A power fuse 30 is connected between the bolts 31 and nuts 32', etc.
At the same time, covers 25 ₃ to 25 ₆ are screwed onto the upper part of each insulating member 24c via waterproof O-rings 33 to seal the power fuse 30 housed therein. Each of the movable electrodes 24 ₁ to 24 ₆ is connected by a base frame 24 f for each of the three phases S, N, and W, and is inserted into and removed from each of the fixed electrodes 23 ₁ to 23 ₆ in units of three phases S, N, and W. Ru. From the fixed electrodes 23 ₁ to 23 ₆ to the movable electrodes 24 ₁ to
The protruding members 26 at both ends of the base frame 24f, which are provided for pulling out the 24 ₆ in a three-pole interlocking system,
a sleeve 26a fixed to the sleeve 26a;
a protrusion 26b protruding from the upper outer periphery of the sleeve 26a; a hole 26c bored in the side wall of the sleeve 26a;
The engager 26 penetrates into the sleeve 26a through the
d, and the engager 2 attached to the outer periphery of the sleeve 26a.
Spring 2 that urges 6d toward the center of the sleeve
6e, the sleeve 26a is loosely fitted around the outer periphery of a core 40 having an engagement groove 40a fixed to the frame 16, and the engagement element 26d is engaged with the engagement groove 40a by the spring force of the spring 26e. It matches. On the other hand, a fulcrum member 27 provided at the upper end of the frame 16 corresponding to the protruding member 26
is composed of a pillar-shaped fulcrum member main body 27a and a protrusion 27b protruding from the outer periphery of the fulcrum member main body 27a. Furthermore, in FIG. 4, the wiring structure on the main lines 20 ₁ and 20 ₂ side, that is, the terminal covers 22 ₁ and 22 _{2 that cover the terminals 22a and 22a} , respectively, and the fixed electrode 2
3 ₁ , 23 ₂ , movable electrodes 24 ₁ , 24 ₂ and cover 2
5 ₁ , 25 ₂ , etc. are configured in the same way as the branch lines 20 ₃ to 20 ₆ , but an auxiliary main line is provided on the main line 20 ₁ side, and connection fittings 24 d and 24 e inside the cover 25 ₁ are provided. The connection member 29 must be used to connect directly between the main line ₂₀ and the cover 2
The difference is that the connection fittings 24d and 24e in 5 ₂ are open, and the main line 20 ₂ is used for auxiliary purposes. Note that each of the N-phase main lines and branch lines 201 _N to 206 _N is connected to terminal covers 22 ₁ to 2
The frame 1 is grounded via the terminal 22a housed in the ₂₆ , the fixed electrode 32, and the zero-phase bus _21N .
6, respectively. Moreover, the movable electrodes 24 ₃ to 24 ₆ and the covers 25 ₃ to
25 ₆ and the power fuse 30 are shown in an exploded perspective view in FIG. 5 and in closed and open states in FIGS. 6a and 6b, respectively. As shown in the exploded perspective view of FIG. 5, the connection fitting 24d has a vertical member V and a plate-shaped fuse mounting plate H integrally formed on the upper end of the vertical member V.
e is plate-shaped like the fuse mounting plate H. 7 to 9 show an example of the configuration of an operating handle used to pull out the movable electrodes 24 ₁ to 24 ₆ upward from the fixed electrodes 23 ₁ to 23 ₆ in a three-pole interlocking manner. That is, FIG. 7a shows a partially cutaway front view of the operating handle, and FIG. 7b shows a right side view of the operating handle. A cylindrical connecting fitting 41 having a substantially U-shaped guide groove 41a for inserting the protrusion 26b of the protruding member 26, a threaded pipe 42 inserted through each opposing side of the connecting fitting 41, and a protruding member at the tip. Approximately R-shaped engagement groove 4 for fitting the 26 protrusions 26b
3a and a guide groove 43b for inserting a threaded pipe 42 near the base, and the rotation angle is regulated by the threaded pipe 42 in the guide groove 43b, so that it can freely rotate within each opposing side of the connecting fitting 41. The stored cylindrical movable tube 43, the screw 44 screwed into the base (that is, the rear end) of each movable tube 43, and the collar 45, which is housed within the side between the opposing sides of the connecting fitting 41 and has both ends.
A tension spring 46 is fixed to the screws 44, 44 through screws 45, respectively, and applies rotational force to the movable tubes 43, 43 in a predetermined direction; a link 49 whose one end is pivoted approximately at the center of the connecting fitting 41 with a pin 48; The other end of 49 is pivoted approximately in the center with a pin 50, and a handle 5 is attached to the rear end.
1a, and a protrusion 2 of a fulcrum member 27 provided at the top end of the frame 16.
7b, and the other end is connected to the handle tube 51 via a handle pin 53, a spring pin 54, and a washer 55.
A handle support 52 is pivotally attached to the tip of the handle support 52. That is, the operating handle is connected to the connecting fitting 4
1. A substantially U-shaped engagement that includes a movable tube 43, a tension spring 46, and a connection release fitting 47, and detachably engages with each protrusion 26 of a pair of protruding members 26 provided on each movable electrode 24 ₁ to 24 ₆ . Joint and handle support 5
The tip of 2 is removably engaged with a protrusion 27b of a fulcrum member 27 provided at the upper end of the frame 16, the approximately center is pivoted to the engaging part via a link 49, and one end is attached to the fulcrum member 27. The handle tube (ie, rod) 51 is pivoted and has a handle 51a at the other end for lifting the engaging portion in a substantially vertical direction about the protrusion 27b. Then, the engaging part is engaged with each protrusion 26 by the connecting fitting 41 and movable tube 43 in the engaging part, and the handle support 52 in the rod 51 is engaged with the protrusion 27b, and the handle 51a in the rod 51 is engaged with the protrusion 27b. By lifting the movable electrodes 24 ₁ to 24 ₆ upward, it becomes possible to separate the movable electrodes 24 1 to 24 6 from the fixed electrodes 23 ₁ to 23 ₆ and lift them upward. Here, the structure for removably engaging the engaging portion with each protrusion 26 is shown in FIGS. 8a, b, c and 9.
As shown in the figure. That is, FIG. 8a is a front view showing the opposite sides of the connecting fitting 41.
The first engaging groove 41a is provided facing each other on the front and back sides of the figure a. Fig. 8b shows the connecting fitting 41
A front view of the movable tube 43 which is rotatably housed in the opposing sides of the movable tube 43, and FIG. It is provided symmetrically to the back. Furthermore, the ninth
The figure is a schematic plan view of the opposite side of the connecting fitting 41 and the movable tube 43, and the movable tubes 43, 43 whose rotation angle is regulated within a predetermined range by the threaded tube 42, are moved by the tension of the spring 46 as indicated by the dashed-dotted line. At the same time, by pulling the connection release fitting 47 to the right, it rotates in the direction of the arrow of the two-dot chain line, which is opposite to the direction of the arrow of the one-dot chain line. And engagement grooves 41a and 43
7a, the openings at their tips are always closed by the tension of the spring 46, crossing each other as shown in FIG.
When the projection 26b is pressed downward, the projection 26b is press-fitted, and the engagement groove 43a rotates against the tension of the spring 46 due to its taper, receives the projection 26b, and then inserts the projection 26b into the engagement groove 41a. hold together. To release this clamped state, pull the connection release fitting 47 to the right in FIG. 9, the engagement groove 43a will rotate and the engagement of the protrusion 26b will be released, and the connection fitting 41 will be lifted upward. This causes the engagement grooves 41a, 43a to separate from the protrusion 26b. In the above configuration, normally, the lid 12 is watertightly closed by the waterproof packing 10 and the branching device main body is stored in the storage box 11, and the power supply current supplied from the power supply side to the main lines 20 ₁ and 20 ₂ is as follows. It flows to the bus bar 21 via the fixed electrodes 23 ₁ , 23 ₂ and the movable electrodes 24 ₁ , 24 ₂ , and further flows from the bus bar 21 to the fixed electrodes 23 ₃ to 23 ₆ and the movable electrodes 24 ₃ to 24 _{6 .}
It flows through the branch lines 20 ₃ to 20 ₆ and is supplied to the load side. A short circuit occurred on the load side and branch line 2
When an overcurrent flows between 0 ₃ and 20 ₆ , power fuse 3
0 is fused and the branch lines 20 ₃ to 20 ₆ where the accident occurred are cut off, so the branch lines 20 ₃ to 20 ₆ and the main line 20
₁ , 20 ₂ and system equipment are protected. Since the power fuse 30 is sealed within the covers 25 ₃ to 25 ₆ on the movable electrodes 24 ₃ to 24 ₆ , in order to replace the blown power fuse 30,
Open the lid 12, hold the operating handle 40 in your hand as shown by the two-dot chain line in FIG. 2c and FIG. Protrusion 27 of fulcrum member 27
b, and the connecting fitting 41 and the movable tube 4
The engagement grooves 41a and 43a of 3 are connected to the movable electrodes 24 ₃ to 2
4 Apply the handle 51a to the protrusion 26b of the protruding member 26 provided at ₆ and push down the handle 51a. Then, the engagement grooves 41a and 43a are easily and reliably engaged with the protrusion 26b. When the handle 51a is lifted upward using the protrusion 27b of the fulcrum member 27 as a fulcrum, the sleeve 26 of the protruding member 26 engaged with the connecting fitting 41
a is pressed against the frame 1 against the pressure force of the engager 26d.
In order to get out of the core 40 fixed to the S,
The movable electrodes 24 ₃ to 24 ₆ connected by the base frame 24f for each of the three N and W phases are separated from the fixed electrodes 23 ₃ to 23 ₆ and lifted upward. In this way, the movable electrodes 24 ₃ to 24 ₆ are connected to the fixed electrode 23 in a three-pole interlocking manner.
Since it can be easily pulled out from ₃ to 23 ₆ , open phase can be prevented, and therefore, the occurrence of adverse effects on system equipment due to open phase can be prevented. Furthermore, the movable electrode 24 ₃
When the power _fuse 30 is pulled out, the power fuse 30 is completely separated and independent from the charging part, ensuring operational safety. Also, by pulling out the movable electrodes 24 ₃ - 24 ₆ , the contact members 23 of the fixed electrodes 23 ₃ - 23 ₆ are removed.
Since a and 23b are exposed upward, voltage detection, phase detection, cable testing, etc. can be easily performed from the road. The pulled out movable electrodes 24 ₃ to 24 ₆ can be used to replace the power fuse 30 on the road.
The work of replacing the power fuse 30 becomes easier. In order to insert the movable electrodes 24 ₃ - 24 ₆ that have completed the replacement work into the fixed electrodes 23 ₃ - 23 ₆ , the protruding member 26 on the movable electrodes 24 ₃ - 24 ₆ side is attached to the connecting fitting 41 of the operating handle 40. At the same time, when the handle support 52 of the operating handle 40 is engaged with the protruding member 27 on the frame 16 side and the handle 51a is pushed down, the sleeve 26a of the protruding member 27 resists the pressure contact force of the engagement member 26d and presses against the frame 16. Side core 4
0, and the contact members 24a, 24b of the movable electrodes ₂₄₃ to ₂₄₆ are fitted to the fixed electrodes ₂₃₃ to _236.
are fitted into the contact members 23a, 23b of the electrodes 2.
4 ₃ to 24 ₆ and 23 ₃ to 23 ₆ are connected. After that, pull the connection release fitting 47 of the operation handle 40 to the right in FIG. 9 to separate the connection fitting 41 and the protruding member 2.
When the engagement state of the movable electrodes 24 3 to 24 6 is released and the operation handle 40 is removed from the projecting member 27 on the frame 16 side, the work of attaching the movable electrodes 24 ₃ to 24 ₆ is completed. In this way, since the movable electrodes 24 ₃ to 24 6 are attached and detached using the operation handle 40, the movable electrodes 24 3 to 24 ₆ are
4 ₃ to 24 ₆ are the operating handle 40 and the frame 16
Since it is always grounded through the cable, it is possible to ensure the safety of attachment/detachment operations. Moreover, the operation handle 40
Because it is easy to attach and detach due to its mechanism, it not only improves work efficiency, but also because the operation handle 40 operates by applying a lever, the fixed electrodes 23 ₃ - 23 ₆ and the movable electrode 24 ₃ are separated by coagulation of silicone grease, etc.
Even if the pull-out force between 24 and ₆ increases, the fixed electrode 2
3 ₃ to 23 ₆ can be easily pulled out. Furthermore, when attaching and detaching the movable electrodes 24 ₃ to 24 ₆ , the main lines 20 ₁ ,
Since there is no need to move 20 ₂ and branch lines 20 ₃ to 20 ₆ , it is not only possible to switch on and off three-phase loads with instant disconnection and instant throw from the road, but also to downsize the entire branching device. . In addition, the fixed electrode 23
₁ to 23 ₆ and movable electrodes 24 ₁ to 24 ₆ can be made by prefabricated assembly, which reduces manufacturing costs and allows for high-voltage multi-circuit opening/closing arrangement of each component. Since it can be arranged in the same way as the equipment, maintenance and inspection are easy. When performing maintenance or inspection on parts other than the power fuse 30, hold the handle 17 of the frame 16 and place the frame 16 on the ground using the guide rail 14 as a guide, as shown by the two-dot chain line in Fig. 2c. By pulling it out, you can easily perform cable terminal processing and cable connection work on the ground. 10 a, b, c and 11 a, b show other embodiments of the present invention, and FIGS. 12 a, b, c and 13 a, b show still other embodiments of the present invention. The same parts as in Figures 2 and 3 are indicated by the same reference numerals, so duplicate explanations will be omitted. It is different from the one in the illustration. That is, the low-pressure branching device shown in FIG. 10 is composed of an outer box 111 that has doors 111a and 111b on the front and top surfaces and is installed on the road, and a main body of the low-pressure branching device housed within the outer box 111. As shown in the single-line diagrams in FIGS. 11a and 11b, the low-voltage branching device main body includes a three-phase, four-wire, two-line main line and eight-line branch line 20 connected to each other via a busbar 21. Cover 2 is between the main line 20 and bus bar 21
The fixed electrode 23 and the movable electrode 2 are connected by a connecting member 29 housed in the fixed electrode 23 and the movable electrode 2.
4, the terminal portion is removably connected to the trunk line 20 covered with a terminal cover 22 and the bus bar, respectively, and its basic configuration is substantially the same as that in FIGS. 2 and 3. In this way, the main body of the low pressure branching device is placed in the outer box 111.
Even when the power fuse 30 is housed inside and installed on the road, the operating handle 40 can be used to insert and remove the power fuse 30 in a three-pole interlocking manner, so that it has substantially the same advantages as the previous embodiment, such as preventing phase loss. In addition, the low pressure branching device shown in FIG. 12 includes an outer box 111 similar to that shown in FIG.
A 3-phase 4-wire 1-line trunk line housed in 1 and 4
It consists of a low-voltage branching device main body for line branching lines. This low-pressure branching device is provided for mounting on pillars, for example, as shown in FIGS. 13a and 13b,
Not only does it have the same advantages as the branching device shown in FIG. 10, but it also has advantages such as being able to downsize the power distribution device. [5] Effects of the invention As explained above, according to the underground low voltage branching device of the invention, the three-phase fixed electrode connected to the bus bar and three-phase branch line is placed on the top of the frame housed in the storage box. At the same time, the power fuses for each phase are housed in the cover and attached to the base frame for each three phases to form multiple pairs of three-phase movable electrodes, and these three-phase movable electrodes are placed on top of the three-phase fixed electrodes. By inserting and removing the power fuses for each of the three phases, the power fuses for each of the three phases can be connected between the bus bar and the three-phase branch line, and the power fuses for each of the three phases can be pulled upward using a removable operation handle. Since the power fuses can be disconnected from each other, the multiple power fuses connected to each phase between the bus bar and the three-phase branch line can be easily and safely inserted and disconnected using a three-pole interlocking method for each three phases. Therefore, phase loss can be prevented, and three-phase load switching, etc., can be performed with immediate disconnection and immediate throw. Furthermore, since the fuses are installed vertically and move up and down vertically, the installation area is reduced and there is no temperature difference between the fuses, and the fuse elements do not sag, improving the fusing characteristics of the fuses. Furthermore, since the entire length of the fuse is covered by a transparent cap, it is easy to check whether the fuse is blown.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a conventional underground low-pressure branching device.
Figures 2a and b are single-line diagrams of the device shown in Figure 3, where Figure a shows the UVW phase, Figure b shows the N phase, and Figures 3a, b, and c are one-line diagrams of the device of the present invention. Figure a is a plan view of the underground low-pressure branching device, figure b is a front view of the same, figure c is a right side view of the same, and figure 4 shows an example.
The figure is a partially enlarged view of the left side of Figure 2b, Figure 5 is an exploded perspective view of the power fuse part in Figure 4, and Figures 6a and b are the closing and opening of the power fuse part in Figure 4. FIG.
Figure 7a and b show the operating handle for attaching and detaching the movable electrode in Figure 2, Figure a is a front view, Figure b is a right side view, and Figure 8a is a right side view. , b, and c show the main parts of the operating handle in Fig. 7. Fig. a is a partial front view of the connecting fitting, Fig. b is a front view of the movable tube, and Fig. C is a central vertical sectional view of Fig. 7. , FIG. 9 is a diagram showing the operating state of FIG. 7, and FIG. 10 is a diagram showing the operating state of FIG.
Figures a, b, and c show other embodiments of the present invention; Figure a is a plan view of the road-installed low-pressure branching device, Figure b is a front view of the same, Figure c is a right side view of the same, and Figure 11. a,
b is a single line diagram of the device of Fig. 10, and figure a is
Figure b shows the UVW phase, and Figure b shows the N phase.
Figures 12a, b, and c show still other embodiments of the present invention, in which figure a is a plan view of a road-installed low-pressure branching device, figure b is a front view of the same, figure c is a right side view of the same, 13a and 13b show an example of installation of the apparatus shown in FIG. 12, with FIG. 13 being a partially cutaway front view and FIG. 13 b being a right side view of the same. Explanation of symbols, 11... Storage box, 12... Lid, 1
6... Frame, 20, 20 ₁ , 20 ₂ ... Main line,
20, 20 ₃ , 20 ₄ , 20 ₅ , 20 ₆ ... branch line,
21... Bus line, ₂₃ , 23 1 , 23 ₂ , 23 ₃ , 2
3 ₄ , 23 ₅ , 23 ₆ ... fixed electrode, 24, 24 ₁ ,
24 ₂ , 24 ₃ , 24 ₄ , 24 ₅ , 24 ₆ ... movable electrode, 25, 25 ₁ , 25 ₂ , 25 ₃ , 25 ₄ , 25 ₅ ,
25 ₆ ...Cover, 26, 27...Protruding member, 2
9... Connection member, 30... Power fuse, 40...
...Operating handle, 41...Connection fitting, 43...Movable tube, 46...Spring, 47...Connection release fitting, 51...Handle tube, 52...Handle strut, 111...Outer box, 111a, 111b... …
door.

Claims (1)

[Claims for Utility Model Registration] Multiple sets of three-phase branches on the load side, including a frame housed in a storage box and connecting a three-phase trunk line on the power supply side and a power fuse via a busbar attached to the frame. In a low-voltage branch device in which lines are interconnected, fixing devices for the three-phase main line and the three-phase branch line are connected to opening/closing ends of the three-phase main line, the three-phase branch line, and the bus bar, respectively. electrodes, and each circuit unit of the three-phase main line and the three-phase branch line is attached to a base frame supported by the frame, and is connected to and released from the fixed electrode for the three-phase main line and the three-phase branch line. and a power fuse connected between the pair of movable electrodes for the three-phase branch line, the power fuse being connected to one of the pair of movable electrodes. a first fuse mounting plate on the side of the upper end of the vertical member having a predetermined length, and a second fuse mounting plate connected to the other electrode of the pair of movable electrodes. supported,
In addition, the movable electrode is watertightly protected by a vertically long transparent cap that allows the whole to be seen through, and the movable electrode is raised and lowered in units of each circuit by an operation handle that is detachably engaged with the base frame. A low-voltage branching device characterized in that the power fuse is connected and disconnected when the power fuse is turned on and opened, and the transparent cap is removed in the open state.