JP4808673B2 - SPD for power supply - Google Patents

Description

  The present invention is a power protection SPD (Surge Protective Device) that protects electrical equipment from lightning strikes with a zinc oxide varistor element. Specifically, it prevents smoke and ignition during abnormal conditions due to deterioration of the zinc oxide varistor element. The present invention relates to a power supply SPD with a separation function.

  A power supply SPD installed on a distribution board of a single-phase AC circuit or a three-phase AC circuit is connected between electric circuits or between an electric circuit and the ground to protect electrical equipment from lightning strikes. The power supply SPD generally has a structure including a main body in which a plurality of types of surge protection circuit components including a zinc oxide varistor element are housed in a rectangular thin insulating casing, and a support base to which the main body is attached. The support base incorporates terminals for connecting the AC circuit and the surge protection circuit component of the main body.

A zinc oxide varistor element used in a power supply SPD is deteriorated by repeated discharge of lightning surges. When the varistor element deteriorates, the leakage current increases and heat is generated. In addition, the varistor element is instantaneously short-circuited when a large surge current exceeding the surge resistance flows, and adversely affects surrounding electrical equipment. Before the varistor element generates heat due to deterioration or excessive surge current, the varistor element is automatically disconnected from the electric circuit to prevent smoke and ignition (see, for example, Patent Document 1). Moreover, the occurrence of an abnormality such as deterioration of the varistor element is displayed and an alarm is issued (see, for example, Patent Document 2).
JP 2006-179842 A JP 2003-102126 A

  A plurality of power supply SPDs used in the distribution board are shipped from the factory in a state where the main body is fitted into the concave portion of the support base to form a single unit, and a plurality (usually 2) are attached to the DIN rail fixed to the distribution board. 4) The unit support is attached in parallel. In order to install a plurality of power supply SPDs on the distribution board in a space-saving manner, the support base and the main body have the same narrow and flat structure. The main body positions and houses a flat zinc oxide varistor element in a flat rectangular insulating casing having a narrow width. As a result, the internal space of the insulating housing of the main body is narrowly limited, and the surge protection circuit parts such as the separation means and abnormality display means that prevent the varistor element from emitting smoke and fire together with the varistor element are reduced in function. It is difficult to install without letting In addition, when a commercially available temperature fuse or current fuse is used as the disconnecting means, the number of surge protection circuit components to be installed in the housing increases, and the cost of the main body increases.

  An object of the present invention is to provide a power supply SPD with a detachment function that can easily store a zinc oxide varistor element and a detachment means in an insulating casing in a functionally stable state.

  In order to achieve the above object of the present invention, a zinc oxide varistor element and an electrode lead-out terminal of the varistor element are joined with a low-melting metal alloy and separated from the electrode lead-out terminal when the low-melting metal alloy melts due to abnormal heat generation of the varistor element. In a power supply SPD having a separating conductor having a spring force and an insulating casing for positioning and holding the varistor element and the separating conductor, the separating conductor is a strip-shaped metal plate and is positioned and held in the casing A fixed portion, a strip-shaped spring portion that is bent and extends in the thickness direction from the distal end side of the fixed portion, and a taper-shaped narrower portion extends from the distal end side of the spring portion, and extends in the extending direction. A current fuse part with a cross-sectional area that is fused with a surge current exceeding the maximum surge current capability of the varistor element, and an electrode lead-out terminal extending widely from the tip of the current fuse part And having a terminal connecting portion to be-joined via a low melt metal alloys.

  Here, a flat zinc oxide varistor element is applied as the varistor element, and the varistor element is positioned and fixed in the insulating casing. The electrode lead-out terminal of the varistor element is connected to the power supply line or the earth line of the AC electric circuit where the power supply SPD is installed via a conductor and is fixed to the varistor element. In a state where the separated conductors are joined to the electrode lead terminals by the low-melting metal alloy, the separated conductors are housed in the casing together with the varistor elements, and each is positioned and fixed. The separating conductor can have a structure in which an electrode lead terminal of the varistor element is integrally connected to an alternating current circuit, or a structure in which a separate electrode terminal is electrically connected. Also, the stripping conductor, which is a strip-shaped metal plate, has a spring property by being deformed by applying an external force in the thickness direction. An appropriate spring property can be given to the spring portion by bending and displacing the strip-like spring portion of the separating conductor in the thickness direction and attaching it in the housing. A flat plate-like current fuse portion having a narrow tip portion is integrally formed between the tip portion of the spring portion and the terminal connection portion. The current fuse portion is set so that the cross-sectional area of the tapered tip portion is melted by an excessive surge current. By doing so, only the tip portion of the current fuse portion is blown by an excessive surge current, and at the time of this blow, the portion behind the tip portion of the current fuse portion remains as an extension of the spring portion. The disconnecting conductor, which is a single metal plate, has both a temperature fuse function that separates the varistor element from the electric circuit due to deterioration heat generation of the varistor element, and a temperature fuse function that separates the varistor element from the electric circuit due to excessive surge current. This eliminates the need for special temperature fuses and current fuses, reduces the number of surge protection circuit components that can be housed in a flat, compact housing, and makes it easy to store each component in the housing with sufficient space. become.

  In the present invention, the terminal connection portion of the separating conductor has a plurality of positioning projections integrally formed at the tip portion in a comb-tooth shape, and the electrode lead terminal of the varistor element is positioned and engaged with the plurality of positioning projections at the tip portion. It can be set as the structure which has the engaging claw which is integrated. Further, the terminal connection portion may have a structure in which connection auxiliary holes through which the low-melting metal alloy flows are formed through a plurality of locations corresponding to the plurality of positioning protrusions in the thickness direction.

  Here, the plurality of positioning protrusions of the separation conductor are arranged in a comb-like shape at intervals of the plate thickness of the electrode extraction terminal formed of a metal plate, and the engagement claw of the electrode extraction terminal is in the tooth groove between the adjacent positioning protrusions. It is inserted and engaged. With the engaging claw engaged between the positioning protrusions, the electrode lead-out terminal and the separating conductor are joined with a low-melting metal alloy, so that accurate joining and joining work is always facilitated, and the low-melting metal alloy is melted. The separation performance when stabilized is stable. In addition, when the relative positional relationship between the electrode lead-out terminal and the separating conductor in the housing is changed in stages, the position of the tooth gap between the positioning protrusions into which the engagement claws of the electrode lead-out terminal are inserted is changed to It is possible to deal with a change in positional relationship.

  Moreover, in this invention, the electrode terminal part which protrudes out of a housing | casing can be integrally formed in the rear-end part opposite to the spring part of a terminal connection part. The electrode terminal part here can be made into the shape which bent the rear-end part of the terminal-connection part in the plate | board thickness direction. When the conductor is separated and housed in the housing, the electrode terminal portion protrudes outside the housing and is connected to an AC circuit terminal installed on a support stand outside the housing.

  According to the power supply SPD of the present invention, the disconnecting conductor of the metal plate housed together with the varistor element in the housing has a thermal fuse function for separating the varistor element from the electric circuit due to the deterioration heat generation of the varistor element, and the varistor element with an excessive surge current. Since it has both functions of current fuse function to disconnect from the electric circuit, there is no need for commercially available temperature fuses or current fuses, and the number of parts of surge protection circuit parts including varistor elements housed in the housing and the manufacturing cost of SPD for power supply Reduction can be achieved. In addition, various surge protection circuit components are provided in the housing with a sufficient space, making it easy to store each component without impairing the functionality of each component, making it easy to manufacture a power supply SPD with stable performance. An excellent effect can be achieved.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  The power supply SPD shown in FIG. 1 includes a main body SP1 and a support base SP2. The main body SP1 has a flat rectangular shape, and is inserted into a concave portion 53 formed at the center of the upper surface of the flat support base SP2 having the same width so as to be insertable from above. As shown in FIGS. 2 and 3, the support base SP2 is detachably attached to a DIN rail 55 fixed to a distribution board 54 or the like.

  The main body SP <b> 1 has a rectangular insulating housing 1, and the flat varistor element 10 is positioned and accommodated inside the housing 1. The housing 1 houses the electrode lead-out conductors 21 and 22 of the varistor element 1 and a display frame 30 for displaying the abnormality of the varistor element 10 to the outside. The display frame 30 is a U-shaped resin frame and is housed in the housing 1 together with a spring material 31 that is slid rightward in FIG.

  The casing 1 integrally includes a top plate portion 1a and a bottom plate portion 1b that are opposed to each other in the vertical direction, side plate portions 1c and 1d that are opposed to each other in the left and right directions in FIG. 1, and a back plate portion 1e shown in FIG. A rectangular insulating cover plate 2 shown in FIG. 2 is attached to the opening of the housing 1 on the side opposite to the back plate portion 1e. The housing 1 here includes a cover plate 2. A rectangular display window 32 as shown in FIG. 4 is formed at the center of the top plate 1a. A protruding fixed guide 40 is integrally projected on one side plate portion 1d of the left and right side plate portions 1c, 1d, and a protruding main body side movable for specifying the type of the main body SP1 below the other side plate portion 1c. A guide 41 is formed. The position of the movable guide 41 can be changed according to the type change of the main body SP1, and the details will be described later. The electrode terminal mounting cuts 24 and 25 are formed at the left and right ends of the bottom plate portion 1b in FIG. 1, and the rectangular cutout 26 is formed in the right half of the bottom plate portion 1b in FIG. As shown in FIGS. 27 and 28, a rectangular plate-like closing plate portion 2 a extending inwardly at a right angle is integrally formed on the lower side of the cover plate 2, and the cover plate 2 is attached to the housing 1. The closing plate portion 2a is fitted into the notch 26 to close it. A rectangular lever insertion hole 2b is formed in the center of the closing plate portion 2a. Further, a rectangular cylindrical frame plate portion 1f shown in FIG. 8 is integrally projected on the inner surface of the back plate portion 1e. A single varistor element 10 is positioned and accommodated in a varistor element accommodation space formed by the inner peripheral surface of the frame plate portion 1f and the inner surface of the back plate portion 1e. The storage space is filled with an insulating protective material 12 so as to cover the varistor element 10. The insulating protective material 12 is solidified to fix the varistor element 10.

  Note that the varistor element 10 in FIGS. 8A and 8B shows an insulating protective material 12. In the varistor element 10 used in the power supply SPD, the rated varistor voltage is proportional to the thickness, and the surge resistance is proportional to the area. There are a plurality of types of varistor elements 10 whose rated varistor voltages are different from 100V, 200V, 400V, and the like. Such multiple types of varistor elements 10 differ in thickness in stages. FIG. 8A shows the high-voltage varistor element 10, and the height h 1 from the inner surface of the back plate 1 e to the surface of the insulating protective material 12 is determined by the thickness of the varistor element 10. FIG. 8B shows the case of the varistor element 10 having a lower pressure than that in FIG. 8A, and the height h2 from the inner surface of the back plate portion 1e to the surface of the insulating protective material 12 is the height h1 in FIG. Smaller than.

  The rectangular flat varistor element 10 has electrode layers on both front and back surfaces, and electrode lead-out conductors (terminals) 21 and 22 are connected to each electrode layer. When the front side of the varistor element 10 in FIG. 1 is the front side, one electrode lead conductor 21 is connected to the electrode lead terminal 11 fixed to the front side electrode layer. The electrode lead-out conductor 21 is the separation conductor according to claim 1 of the present invention. Hereinafter, the conductor 21 is referred to as a separated conductor 21. The electrode lead-out conductor 22 connected to the other back-side electrode layer of the varistor element 10 does not necessarily have to be a separated conductor structure, and hence will be referred to as an electrode lead-out conductor 22 hereinafter. When the main body SP1 is used for an AC electric circuit, the separation conductor 21 is connected to the power supply line, and the electrode lead conductor 22 is connected to the earth line.

  The separating conductor 21 is joined to the electrode lead terminal 11 fixed to the surface side electrode layer of the varistor element 10 with a low melting metal alloy 13, and the electrode lead terminal 11 is melted when the low melting metal alloy 13 is melted due to abnormal heat generation of the varistor element 10. It has a spring force that is disconnected from. A specific example of the electrode lead-out terminal 11 of the varistor element 10 is shown in FIG. 6, and an example of a normal shape having no spring force of the separating conductor 21 is shown in FIG.

  The electrode lead terminal 11 shown in FIG. 6 is formed by bending a belt-like metal plate having good thermal conductivity into a gate shape. The electrode lead terminal 11 has a base end portion 11 a that rises from the surface-side electrode layer of the varistor element 10 through the insulating protective material 12. A flat plate-like intermediate portion 11b extends from the upper end of the base end portion 11a across the frame plate portion 1f. A flat conductor connecting portion 11c is bent from the tip of the intermediate portion 11b toward the back plate portion 1e. The conductor connecting portion 11c is inclined at a predetermined angle with respect to the frame plate portion 1f. A pair of engaging claws 11d and 11e project outwardly at the upper and lower end portions of the tip approaching the frame plate portion 1f with the conductor connecting portion 11c inclined. When the thickness direction of the varistor element 10 is the vertical direction, the pair of engaging claws 11d and 11e are positioned in the upper and lower stages and face each other in parallel. The intermediate portion 11b has a length and a shape that quickly conducts heat generated when the varistor element 10 is abnormal to the conductor connecting portion 11c.

  The separation conductor 21 in FIG. 7 is a belt-like elastic metal plate, and is positioned and held on the bottom plate portion 1 b of the housing 1. The separating conductor 21 has a flat plate-like fixing portion 21a that is positioned and held at the left half position in FIG. 1 of the bottom plate portion 1b. A strip-shaped spring portion 21b extends on the distal end side (right side in FIG. 7) of the fixed portion 21a. The spring portion 21b is a displaceable portion that bends in the plate thickness direction, and retains spring properties by bending in the plate thickness direction. A trapezoidal plate-like current fuse portion 21c that is tapered and extends from the distal end side of the spring portion 21b extends. A rectangular flat-plate-shaped terminal connecting portion 21d extends from the tip of the current fuse portion 21c. The tip portion of the current fuse portion 21c is set to have a cross-sectional area that is melted by a surge current exceeding the maximum surge current withstand capability of the varistor element 10. The terminal connection portion 21 d is surface-bonded to the conductor connection portion 11 c of the electrode lead-out terminal 11 via the low melting metal alloy 13. The terminal connection portion 21d integrally has a plurality of positioning projections 21e protruding in a comb-like shape on the tip side. The plurality of positioning protrusions 21e are arranged in a comb-like shape in a plurality of upper and lower stages when the thickness direction of the varistor element 10 is set in the vertical direction, similarly to the engaging claws 11d and 11e of the electrode lead-out terminal 11.

  The separation conductor 21 has a connection auxiliary hole 14 that penetrates in a plate thickness direction at a plurality of locations of the terminal connection portion 21d. The connection auxiliary hole 14 is formed at a location corresponding to the plurality of positioning protrusions 21e. In the connection auxiliary hole 14, the molten low-melting metal alloy 13 flows to improve the electrical and mechanical connection between the terminal connection portion 21 d and the conductor connection portion 11 c.

  The disconnected conductor 21 integrally has an electrode terminal portion 21f bent in the plate thickness direction of the terminal connection portion 21d at the rear end portion of the terminal connection portion 21d opposite to the spring portion 21b. The electrode terminal portion 21f is a plug-in type electrode terminal obtained by bending a metal plate into a rhombus shape. A connecting portion of the electrode terminal portion 21f with the terminal connection portion 21d is fitted into the left notch 24 in FIG. 1 of the bottom plate portion 1b of the housing 1, and the electrode terminal portion 21f protrudes from the bottom plate portion 1b to the outside. The fixing portion 21a of the separating conductor 21 is positioned and held in parallel on the bottom plate portion 1b. The spring portion 21b extending from the tip of the fixed portion 21a bends upward in FIG. 1 and retains a spring force in a direction to separate the terminal connection portion 21d from the conductor connection portion 11c of the electrode lead terminal 11.

  The joining of the terminal connecting portion 21d of the separating conductor 21 and the conductor connecting portion 11c of the electrode lead-out terminal 11 with the low melting metal alloy 13 is performed as follows. The varistor element 10 accommodated in the housing 1 is one of a plurality of types having different thicknesses. The electrode lead-out terminal 11 and the separation conductor 21 can be used in common for any of a plurality of types of varistor elements, and any type can be joined under the same conditions. This will be described with reference to FIGS.

  The height h1 shown in FIG. 8A and the height h2 shown in FIG. 8B are different in two steps. Therefore, if the electrode lead terminals 11 having the same size and shape are commonly used for the varistor elements 10 shown in FIGS. 8A and 8B, the relative heights of the electrode lead terminals 11 shown in FIGS. The relationship is different in two stages. Corresponding to this stepwise difference in height relationship, the number and interval of the comb-like positioning projections 21e at the tip of the separation conductor 21 are determined. For example, in the case of FIG. 8A, the upper and lower engaging claws 11d and 11e of the electrode lead terminal 11 at the height position corresponding to the height h1 are at the uppermost stage in FIG. The positioning protrusion 21e is sandwiched. In this case, the upper engaging claw 11d is engaged with the uppermost positioning protrusion 21e, and the lower engaging claw 11e is placed between the uppermost positioning protrusion 21e and the second-most positioning protrusion 21'e. It is inserted and engaged with the tooth gap. By this engagement, the electrode lead-out terminal 11 and the separation conductor 21 are positioned easily and reliably with each other, and the joining with the low-melting metal alloy 13 is easily and reliably performed.

  In the case of FIG. 8B, the upper engaging claws 11d and the lower engaging claws 11e at the height position corresponding to the height h2 are separated from the positioning protrusions 21e of the conductor 21 by separating the engaging claws 11e at the upper stage. In FIG. 8, the two positioning protrusions 21 ′ e and 21 ′ e on the lower side in FIG. In the case of FIG. 8B as well, the electrode lead-out terminal 11 and the separating conductor 21 are simply and reliably positioned under the same conditions as in FIG. 8A, and the joining with the low-melting metal alloy 13 is easily and reliably performed. Further, by using the electrode lead terminal 11 and the separating conductor 21 in common for a plurality of types of varistor elements, the housing 1 and the cover plate 2 can be shared. With this commonization, the external dimensions of the plurality of types of main bodies SP1 classified by the varistor elements can be made the same, and the support base SP2 can be configured to be used in common with the plurality of types of main bodies SP1.

  The electrode lead conductor 22 that forms a pair with the separation conductor 21 is a strip-shaped metal plate disposed along the inner surface of the side plate portion 1d on the right side in FIG. The upper part of the electrode lead conductor 22 in FIG. 1 is fixed to the back electrode layer of the varistor element 10, and the electrode terminal part 22f is integrally formed at the lower part. The electrode terminal portion 22f is a plug-in type electrode terminal that is paired with the electrode terminal portion 21f of the separation conductor 21, and is inserted into the right-side cut 25 in FIG. 1 of the bottom plate portion 1b of the housing 1 and protrudes to the outside. A pair of electrode terminal portions 21f and 22f on the power supply line side and the earth line side face each other in parallel at both ends of the lower surface of the bottom plate portion 1b. By separating one of the pair of electrode terminal portions 21f and 22f and integrally forming the conductor 21, the number of components to be mounted on the main body SP1 can be reduced, and the cost can be reduced.

  The varistor element 10 is assembled in the housing 1 as follows, for example. The cut conductor 21 and the electrode lead conductor 22 are assembled to the varistor element 10, and the varistor element 10 is inserted into the housing 1. At this time, the spring portion 21 b of the separating conductor 21 is bent to position the fixed portion 21 a on the bottom plate portion 1 b of the housing 1. At the same time, the electrode lead conductor 22 is attached to the housing 1. Thereafter, the insulating protective material 12 is filled and solidified so as to cover the varistor element 10. Next, the display frame 30 is housed in the housing 1 together with the spring material 31, and the lid plate 2 is fitted into the housing 1 and attached in a manner that assembles the main body SP1.

  Before describing the operation of the separation conductor 21 in FIGS. 11 and 12, the display frame 30 that operates in association with the separation conductor 21 will be described with reference to FIGS. 9 and 10. FIG.

  A display frame 30 shown in FIG. 11 is housed in the housing 1 so as to be slidable in the left-right direction in FIG. The display frame 30 is a resin insulator, and a flat insulating plate 30a and an abnormal display plate 30b are integrally connected by a connecting frame 30c. The insulating plate 30 a is a rectangular plate parallel to the bottom plate portion 1 b of the housing 1, and is disposed close to the fixing portion 21 a of the separation conductor 21. As shown in FIG. 10, both end portions of the insulating plate 30 a are fitted into guide grooves 35 and 36 formed on the back plate portion 1 e of the housing 1 and the inner surface of the lid plate 2. The guide grooves 35 and 36 extend linearly in the left-right direction in FIG. 1, and guide the back-and-forth movement of the insulating plate 30a. A rod-shaped spring holding 30d is integrally formed by protruding backward from the rear end portion on the left side of the insulating plate 30a in FIG. A coil-shaped spring material 31 is inserted into the spring holding 30d, and the spring material 31 is held so as to be expandable and contractable in the axial direction. When the insulating plate 30a is inserted into the housing 1, a compressed spring material 31 is inserted between the rear end of the insulating plate 30a and the side plate portion 1e of the housing 1, and the insulating plate 30a is moved to the right in FIG. Energize in the forward direction. The front end of the insulating plate 30 a is engaged with the concave surface side of the spring portion 21 b bent in a concave shape, which is a displaceable portion of the separating conductor 21. The spring portion 21 b here acts as a stopper that stops the advance of the insulating plate 30 a urged by the spring material 31. Further, the urging force of the bent spring portion 21b by the insulating plate 30a acts as a spring force in a direction in which the terminal connecting portion 21d on the distal end side is separated from the electrode lead terminal 11 from the spring portion 21b, and the separation conductor 21 to be described later is separated. Make the operation more reliable. When the bent spring portion 21 b is displaced to a flat state before the bending, the engagement with the tip of the insulating plate 30 a is released, and the insulating plate 30 a is advanced by the bias of the spring material 31. With this advance, the insulating plate 30 a is separated and moved to an intermediate position between the conductor 21 and the electrode lead terminal 11.

  The abnormal display plate 30b of the display frame 30 is a rectangular flat plate facing in parallel with the insulating plate 30a. The both ends of the connection frame 30c are integrally connected to the rear end of the front side in FIG. 9 of the abnormality display plate 30b and the insulating plate 30a. The abnormality display plate 30b is inserted and held in a gap g between the top plate portion 1a and the frame plate portion 1f of the housing 1. The gap g guides the abnormality display plate 30b to move back and forth in the left-right direction in FIG. The upper surface of the abnormality display plate 30b is color-coded into, for example, a white portion 31 and a red portion 32. When the insulating plate 30 a is separated and locked to the spring portion 21 b of the conductor 21 and is in a fixed position, the white portion 31 of the abnormality display plate 30 b closes the display window 32 of the housing 1. When the entire display frame 30 advances rightward in FIG. 1, the red portion 32 of the abnormality display plate 30 b closes the display window 32 of the housing 1. By visually recognizing the color in the display window 32 from the outside of the housing 1, it can be seen at a glance whether an abnormality such as varistor element deterioration has occurred in the main body SP1.

  By inserting the main body SP1 into the concave portion 53 of the support base SP2, the main body SP1 and the support base SP2 are electrically and mechanically connected to each other, and one unit of power supply SPD is configured. The support base SP2 has a function of transmitting an abnormality of the main body SP1 to a remote place. Before the detailed description of the support base SP2, the operation when an abnormality occurs in the main body SP1 will be described with reference to FIGS.

  FIG. 11 shows the occurrence of abnormality when the varistor element 10 deteriorates and generates heat. Heat generated by the deterioration of the varistor element 10 is conducted through the electrode lead terminal 11, and the low-melting metal alloy 13 is melted. Then, the terminal connection portion 21d is separated from the conductor connection portion 11c of the electrode lead terminal 11 by the spring force of the spring portion 21b bent of the separating conductor 21, and the spring portion 21b and its tip portion are parallel to the bottom plate portion 1b of the housing 1. Displace to the position that becomes. With this displacement, the electrical connection between the electrode lead-out terminal 11 and the separating conductor 21 is interrupted, and the varistor element 10 is disconnected from the electric circuit to prevent smoke and ignition.

  At the same time, the display frame 30 moves forward with a fixed stroke from the fixed position to the right in FIG. With this advance, the red portion 32 of the abnormality display plate 30b moves to the display window 32 of the housing 1, and the occurrence of abnormality is displayed outside. Further, as the display frame 30 advances, the insulating plate 30a is inserted between the conductor connecting portion 11c of the electrode lead terminal 11 and the terminal connecting portion 21d of the separating conductor 21, and the advancement stops at that position. When the abnormality shown in FIG. 11 occurs, the insulating plate 30a of the display frame 30 moves between the conductor connecting portion 11c and the terminal connecting portion 21d where the electrode lead-out terminal 11 and the separating conductor 21 are closest to each other, so that the conductor connecting portion 11c and the terminal are connected. The insulation of the connecting portion 21d is ensured. Further, the forward movement of the insulating plate 30a assists the displacement operation of the spring portion 21b of the separation conductor 21 and the front portion thereof, and the separation operation of the separation conductor 21 is performed reliably.

  FIG. 12 shows the occurrence of an abnormality when an excessive surge current exceeding the surge resistance flows through the varistor element 10. When an excessive surge current exceeding the surge resistance flows instantaneously in the electric circuit of the varistor element 10, the excessive surge current is disconnected and flows into the current fuse portion 21c of the conductor 21, and the tip portion of the current fuse portion 21c is melted to be fused to the terminal connection portion 21d. Detached from. Since the current fuse portion 21c is blown instantaneously, the low melting metal alloy 13 may not melt. Due to the melting of the current fuse portion 21c, the bent spring portion 21b of the separating conductor 21 is displaced to a position parallel to the bottom plate portion 1b of the housing 1. With this displacement, the electrical connection between the electrode lead-out terminal 11 and the separating conductor 21 is interrupted, and the varistor element 10 is disconnected from the electric circuit to prevent smoke and ignition. At the same time, the display frame 30 advances from the fixed position to the right in FIG. 12 with a fixed stroke. With this advance, the red portion 32 of the abnormality display plate 30b moves to the display window 32 of the housing 1, and the occurrence of abnormality is displayed outside. Further, as the display frame 30 moves forward, the insulating plate 30a is inserted between the terminal connection portion 21d remaining in the conductor connection portion 11c of the electrode lead-out terminal 11 and the distal end portion of the spring portion 21b of the disconnected conductor 21 and stops. Even when the abnormality of FIG. 12 occurs, the insulation of the conductor connecting portion 11c and the terminal connecting portion 21d is ensured by the movement of the insulating plate 30a between the electrode lead terminal 11 and the separating conductor 21. Further, the forward movement of the insulating plate 30a assists the displacement of the spring portion 21b of the separating conductor 21, thereby ensuring the current fuse function.

  In addition, the chain line of FIG. 11 and FIG. 12 is the displacement interlocking member 70 mentioned later. The displacement interlocking member 70 is installed in the support base SP2 so as to be swingable up and down. When a plurality of main bodies SP1 are arranged and used in parallel, the displacement interlocking members of adjacent main bodies SP1 are connected to each other.

  Next, details of the support base SP2 will be described.

  A support base SP2 shown in FIG. 1 includes a housing 51 of a resin molded product corresponding to the housing 1 of the main body SP1. Hereinafter, the main body side casing 1 is referred to as a first casing 1, and the support base side casing 51 is referred to as a second casing 51. The second casing 51 has a U-shaped base section B1 having a U-shaped longitudinal section, and a vertically extending section B2 having a U-shaped cross section extending right above both longitudinal ends of the base section B1. , B3. The base portion B1 has an upper plate portion B1a, a back plate portion B1b, and a lower plate portion B1c that are continuous in a U-shaped longitudinal section. The displacement interlocking member 70 is installed inside the base part B1. The hanging portion B2 includes an inner wall portion B2a, a top surface portion B2b, an outer wall portion B2c, and a back plate portion B2d obtained by extending the back plate portion B1a of the base portion B1. The other hanging portion B3 has an inner wall portion B3a, a top surface portion B3b, an outer wall portion B3c, and a back plate portion B3d obtained by extending the back plate portion B1a of the base portion B1. A terminal mechanism 80 is installed inside each hanging part B2, B3. If the front side in FIG. 1 of the second casing 51 is the front side and the opposite side is the rear side, the front side of the second casing 51 opens, and one lid plate 52 is attached to the opening end. The rear surface side of the second housing 51 is a continuous back plate portion B1b, B2d, B3d.

  A displacement interlocking member 70 is installed in the center of the base B1 so as to be swingable up and down. The contact output mechanism 56 is installed in the base part B1 and the hanging part B2. The contact output mechanism 56 can constitute means for performing an on / off contact operation when an abnormality occurs in the varistor element 10 of the main body SP1 and transmitting the occurrence of the abnormality in the varistor element 10 to a remote place by an electrical signal. The contact output mechanism 56 includes a contact part 56a that performs a contact operation and a contact output part 56b wired to the contact part 56a. The contact part 56a is, for example, a limit switch, and is connected to and fixed to the displacement interlocking member 70 in the base part B1 of the second housing 51. The contact part 56 a performs an on / off contact operation in conjunction with the swing of the displacement interlocking member 70. The contact output component 56b is fixed to the lower portion of the outer wall portion B2c of the hanging portion B2. The contact output component 56 can constitute means for transmitting an electrical signal indicating the occurrence of an abnormality to a remote management center (not shown) when an abnormality occurs in the main body SP1 and the contact component 56a is turned on. Commercially available products can be applied to the contact part 56a and the contact output part 56b.

  A rail mounting part 58 is installed on the lower surface of one end of the base part B1 so as to be movable in the left-right direction in FIG. As shown in FIG. 2, when the support base SP <b> 2 is attached to the DIN rail 55, the inner end of the rail attachment component 58 is locked to the lower surface of the side end portion of the DIN rail 55. When the rail attachment component 58 is manually moved in the right direction in FIG. 2, the locking with the DIN rail 55 is released and the support base SP2 is removed. Bolt mounting holes 101 and 102 are formed at two places on the left and right sides of the back plate B1b of the base part B1, and bolt insertion holes 103 and 104 are formed at two places on the left and right sides of the bottom plate 52. The bolt insertion holes 103 and 104 are cylindrical, and the tip openings communicate with the corresponding bolt mounting holes 101 and 102. As shown in FIGS. 23 and 24, each of these holes has two connection bolts (not shown) when a plurality of (three in the drawing) support bases SP2 are connected in parallel and connected in series. Used as an insertion hole.

  The main body SP1 is removably inserted into the recess 53 of the second casing 51 from above. Both inner wall surfaces facing the recess 53 are tapered surfaces that slightly open upward so that the main body SP1 can be easily inserted and removed. Further, as shown in FIG. 13, both inner wall surfaces are provided with a longitudinal groove-shaped body direction regulating fixing guide 60 that regulates the directionality of the body SP1 to be inserted, and a longitudinal groove for specifying the type of the body SP1. A movable guide 61 for identifying the shape type. Correspondingly, the first housing 1 of the main body SP1 has a protruding fixed guide 40 on the side surface on the ground line side which is one of both side surfaces in the vertical direction, and a protruding type on the side surface on the power line side. The specifying movable guide 41 is provided in the vertical direction. The protruding body-side fixed guide 40 is inserted into only the groove-like support base side fixed guide 60 and is not inserted into the support base side movable guide 61. Similarly, the number, width, and formation location of each guide are set so that the protruding body-side movable guide 41 is inserted into only the groove-like support base-side movable guide 61 and is not inserted into the support base-side fixed guide 60. I have decided. For example, the protrusion-shaped main body side fixing guide 40 is formed at one place off the center in the width direction of the side surface of the first housing 1. Corresponding to this, the groove-shaped fixing guide 60 of the second housing 51 is formed at one place off the center in the width direction of the inner wall B3a of the hanging part B3. Specific examples of the main body side movable guide 41 and the support base side movable guide 61 will be described with reference to FIGS.

  The support base side movable guide 61 shown in FIG. 13 is made to correspond to three types of main bodies SP1. The support base side movable guide 61 has two movable guide grooves 64 that cross in a vertical and horizontal cross at the upper part of the inner wall surface of the hanging part B <b> 2 of the second housing 51. Three parallel fixed guide grooves 63 are formed in the vertical direction at the lower portion of the inner wall surface of the hanging portion B2. The groove widths of the guide grooves 63 and 64 are the same so that the protruding main body side movable guide 41 can be inserted. A movable guide groove 64 is formed in the upper part of the inner wall B2a so that the position can be changed vertically and horizontally. The movable guide groove 64 is formed on the front surface of a square resin switching plate 66 as shown in FIG. The switching plate 66 is fitted into a square mounting groove 65 formed in the upper part of the inner wall portion B2a so as to be detachable from right above. As shown in FIGS. 15A and 15B, when the switching plate 66 is inserted into the mounting groove 65, there are three grooves in the longitudinal direction of the movable guide groove 64 intersecting the cross of the switching plate 66. The fixed guide groove 63 communicates with one central line. FIGS. 16A and 16B show that the switching plate 66 of FIG. 15A is pulled out from the mounting groove 65 and rotated 90 ° to the right, and inserted into the mounting groove 65 as it is. In the case of FIG. 16, one groove in the longitudinal direction of the switching plate 66 communicates with the rightmost one in FIG. 16 of the three fixed guide grooves 63. When the switching plate 66 of FIG. 15 is pulled out of the mounting groove 65 and rotated 90 ° to the left and is inserted into the mounting groove 65, one groove in the longitudinal direction of the switching plate 66 is the left end of the three fixed guide grooves 63. Communicate with Article 1.

  The movable guide 41 of the first housing 1 includes a resin guide part 67 shown in FIGS. 18 and 19 and a resin spacer part 68 as shown in FIGS. The guide component 67 includes a U-shaped guide projection 67a, a mounting base 67b that forms a rectangular frame with the guide projection 67a, and a portal-shaped slide portion 67c that extends in the orthogonal direction from the mounting base 67b. . Two parallel mounting slits 4 as shown in FIG. 20 are formed in the side plate portion 1 c of the first housing 1 corresponding to the guide component 68. A vertically long mounting hole 69 formed by the guide projection 67a and the mounting base 67b of the guide part 67 is inserted into the side plate 1'c between the two mounting slits 4, and the guide projection 67a is inserted into the outer surface of the side plate 1c. The guide part 67 is removably inserted into the mounting slit 4 by projecting to the side and sliding the slide part 67c to the inner surface side of the side plate part 1c.

  As shown in FIG. 20, the spacer part 68 is inserted into the two mounting slits 4, then the guide part 67 is inserted, and finally the cover plate 2 is attached to the first housing 1. Two presser claw portions 3 projecting integrally from the side of the lid plate 2 at the side end of the lid plate 2 are fitted into the mounting slit 4, and the space component 68 and the guide component 67 are positioned and held in the mounting slit 4. In the case of the attachment procedure of FIG. 20, as shown in FIGS. 17A and 17B, the guide protrusion 67 a of the guide component 67 is positioned at the center of the side plate portion 1 c to become the main body side movable guide 41. The first housing 1 in the state of FIG. 17 can be inserted into and removed from only the second housing 51 in the state of FIG.

  In the attachment procedure of FIG. 20, when the guide component 68 shown in FIG. 20 is rotated 180 ° horizontally and inserted into the attachment slit 4, the result is as shown in FIG. In this case, the guide protrusion 67a of the guide component 67 is positioned at a fixed position on the right side of the center of the side plate portion 1c and becomes the main body side movable guide 41. Further, when the guide part 68 is inserted into the attachment slit 4 before the space part 68 in the attachment procedure of FIG. 20, the result is as shown in FIG. In the case of FIG. 22, the guide protrusion 67 a of the guide component 67 is positioned at a fixed position on the left side of the center of the side plate portion 1 c to become the main body side movable guide 41. The first casing 1 in the state of FIG. 22 can be inserted into and removed from only the second casing 51 in the state of FIG.

  The main body SP1 having the first housing 1 is specified by the type of varistor element in the manufacturing process. At the stage of manufacturing the main body, the position of the guide protrusion 67a of the guide component 67 that protrudes from one side surface of the first housing 1 is determined. Moreover, when the kind of main body SP1 attached to support stand SP2 is decided, the direction of the switching plate 66 of the 2nd housing | casing 51 is decided according to the kind. In this way, different types of main bodies SP1 cannot be inserted into the support base SP2, and the type specification between the support base SP2 and the main body SP1 can be accurately performed.

  Next, the displacement interlocking member 70 installed in the second casing 51 of the support base SP2 and the terminal mechanism 80 will be described in order.

  The displacement interlocking member 70 functions when a plurality of support bases SP2 are used in parallel. 23 and 24 show three support stands SP2 joined to each other and installed in parallel, and each is arranged between a power line and an earth line of the same single-phase AC circuit. In FIG. 23, only the central one of the three parallel support bases SP2 is equipped with the contact output mechanism 56 and the rail mounting part 58. A displacement interlocking member 70 having the same structure is installed in the second casing 51 of each of the three support bases SP2 arranged in parallel, and adjacent ones are connected to each other. The displacement interlocking members 70 of the three support bases SP2 are connected in series and perform the same operation when an abnormality occurs in the main body SP1.

  In addition, the code | symbol 90 of FIG. 24 is a grounding terminal board, and is inserted by the support stand SP1 of 3 units | sets parallel so that insertion / removal is possible from the near side in FIG. As will be described later, the ground terminal plate 90 is commonly connected to the ground terminals of the three support bases SP1.

  The displacement interlocking member 70 will be described with reference to FIGS. 25 and 26. The displacement interlocking member 70 is a resin molded product as a whole, and includes a linear lever main body portion 70a and a lever operation portion 70b extending upward from the tip end portion of the lever main body portion 70a. A pin-shaped connecting bar portion 70c and a cylindrical bar insertion portion 70d are integrally formed on both sides of the central portion of the lever main body portion 70a. The bar insertion part 70d has a connection hole 71 having an inner diameter into which the distal end of the connection bar part 70c is removably inserted. The center lines of the connecting hole 71 and the connecting bar portion 70c are coincident with each other. A contact operating portion 70e is formed below the center portion of the lever main body portion 70a. A pair of support pin portions 70f protrudes in opposite directions by 180 ° on both sides of the rear end portion of the lever main body portion 70a.

  A single displacement interlocking member 70 is attached to the second housing 51 of one support base SP2 as follows. One support pin portion 70f of the displacement interlocking member 70 is inserted into a cylindrical pin receiving portion 72 protruding from the inner surface of the back plate portion B1b of the second housing 51. The lever main body portion 70a is brought close to the upper plate portion B1a of the second casing 51, the lever operation portion 70b is inserted into a rectangular lever insertion hole 72 formed in the upper plate portion B1a, and protruded from the upper plate portion B1a. At this time, the contact operating unit 70e is connected to the contact part 56a. When the cover plate 52 is fitted to the second casing 51, a cylindrical pin receiving portion 73 protruding from the inner surface of the cover plate 52 is inserted into the other support pin portion 70f. The front end surface of the bar insertion portion 70d of the displacement interlocking member 70 is opposed to the connection hole 74 formed in the back plate portion B1b of the second housing 51. The pin-shaped tip portion of the connecting bar portion 70 c is protruded from the connecting hole 75 formed in the lid plate 2.

  Three support bases SP2 are joined in parallel with the directivity aligned so that the power line side (or ground line side) is in the same direction, and connected in series by passing through connecting bolts (not shown) in the parallel direction. To do. At this time, as shown in FIG. 25, the distal end portion of the connecting bar portion 70c protruding from one of the two adjacent support bases SP2 is inserted into the connection hole 71 of the bar insertion portion 70d of the other support base SP2 to be connected. To do. As shown in FIG. 25, when three support bases SP2 are connected, the connecting bar portion 70c protrudes from one support base SP2 at either the left or right end. Such a protruding portion may be finally cut and removed as shown by a chain line in FIG.

  23 and 24 show the case where the main body SP1 is fitted in each of the recesses 53 of the three support bases SP2 connected in parallel. The varistor elements 10 of the three main bodies SP1 are normal, and the spring portion 21b of the separating conductor 21 is in a normal state bent upward. The lever operating portion 70b of the displacement interlocking member 70 protrudes at a predetermined length on the bottom surface of the recess 53 of the support base SP2. When the main body SP1 is fitted into the concave portion 53 to a predetermined position, as shown partially in FIG. 2, the tip of the lever operating portion 70b protruding from the bottom surface of the concave portion 53 contacts the lower surface of the bent spring portion 21b in the main body SP1. Or approach.

  The upper ends of the three support bases SP2 in FIG. 23 are wired to the power line side of the AC circuit, and the lower ends are wired to the ground line side. When an abnormality occurs in any one of the three main bodies SP1 supported by the three support bases SP2, the disconnecting conductor 21 of the abnormality generating support base SP2 performs the electric circuit disconnecting operation described with reference to FIG. 11 or FIG. At this time, the spring portion 21b of the separating conductor 21 is displaced downward, and the lever operating portion 70b of the displacement interlocking member 70 is pushed down. By this depression, the lever main body 70a swings downward with the support pin 70f as a fulcrum. Since the displacement interlocking members 70 of the three support bases SP2 are connected to each other, if the main body SP1 of any one support base SP2 is abnormal and the displacement interlocking member 70 swings as described above, Even when the main body SP1 of the remaining two support bases SP2 is in a normal state, the displacement interlocking members 70 of the remaining two support bases SP2 also swing integrally.

  In the three support bases SP2 shown in FIG. 23, the contact output mechanism 56 is provided only on the central support base SP2. When an abnormality occurs in any one main body SP1 of the three support bases SP2, the displacement interlocking members 70 of the three support bases SP2 integrally swing together. When the lever main body portion 70a of the displacement interlocking member 70 of the central support base SP2 swings downward, the contact operating portion 70e turns on the contact component 56a of the contact output mechanism 56, so that the remote location (management center) ) Can be configured to transmit an abnormal electrical signal. This abnormality signal notifies a remote place that an abnormality has occurred in one of the three main bodies SP1, and does not include information on which of the three main bodies SP1 has an abnormality. The three main units SP1 are incorporated as one unit in the AC circuit, and if an abnormality occurs in any one of the three units, inspection and management such as replacement of the main unit are performed. Therefore, it is not always necessary to transmit information on which of the three units has an abnormality.

  Further, the contact output mechanism 56 can be provided on any of the three support bases SP2. In this case, when any one of the three displacement interlocking members 70 of the three support bases SP2 swings, the remaining two displacement interlocking members 70 also swing integrally, and the same body from each of the three support bases SP2. Means for transmitting an electrical signal indicating the occurrence of an abnormality to a remote location can be configured. The contents of the electric signal transmission of the abnormality occurrence from these three units are the same as the transmission contents from only one unit. Therefore, there is no need to equip each of the three support bases SP2 with the contact output mechanism 56, and it is only necessary to equip at least one of the three support output mechanisms 56 with the contact output mechanism 56. Thus, by providing the contact output mechanism 56 only on one support base SP2, the number of parts of the SPD of three units and one unit can be reduced, and the wiring work of the minimum number of contact output mechanisms 56 becomes easy.

  Next, the terminal mechanism 80 of the support base SP2 shown in FIG. 1 will be described. In FIG. 1 of the second housing 51, the terminal mechanisms 80, 80 having the same structure are installed symmetrically on the left and right hanging portions B2, B3. The left terminal mechanism 80 will be described with reference to FIG. FIG. 29 shows an enlarged side sectional view of the terminal mechanism 80 when the terminal is attached.

  The terminal mechanism 80 includes an electrode terminal plate 81 that is fitted and inserted along a terminal receiving plate B2e that is erected integrally with the back plate portion B2d of the hanging portion B2 of the second housing 51. The electrode terminal plate 81 is formed by bending a strip-shaped metal plate in a meandering manner in the plate thickness direction, and has a flat outer end portion 81a and an inner end portion 81b bent in a U shape. A screw terminal 82 for fastening and connecting a terminal plate (not shown) from the power line of the AC electric circuit is screwed to the outer end 81 a of the electrode terminal plate 81. The inner end 81b of the electrode terminal plate 81 is installed in the base part B1 of the second casing 51, and faces the terminal connection hole 110 (see FIG. 13) formed in the upper plate part B1a of the base part B1. . The terminal connection hole 110 is a rectangular hole into which one electrode terminal portion 21f protruding from the lower surface of the main body SP1 can be inserted and removed. The electrode terminal portion 21f inserted into the terminal connection hole 110 is press-fitted into the U-shaped inner end portion 81b of the electrode terminal plate 81, and electrical and mechanical connection between the terminals is performed. The screw terminal 82 has a head portion 82a and a rod-like screw portion 82b. Two washers 83 and 84 are inserted into the screw portion 82b, and the lower end portion of the screw portion 82b is screwed to the outer end portion 81a of the electrode terminal plate 81. Combined. The terminal mechanism 80 includes a screw holding spring 85 as shown in FIG.

  The screw holding spring 85 is a wire spring, a semi-arc-shaped screw engaging portion 85a, and a pair of end portions extending in a horizontal direction from both ends of the screw engaging portion 85a and then extending upward in a reverse C shape. 85b and 85c. When the screw engaging portion 85a is elastically deformed and fitted to the screw portion 82b of the screw terminal 82, the screw engaging portion 85a is restored and engaged with the screw portion 82b. The screw engaging portion 85a is fitted between, for example, the upper and lower washers 83 and 84 of the screw portion 82b. Both end portions 85b and 85c of the screw holding spring 85 are along the back plate portion B2d of the hanging portion B2 of the second casing 51, and the tip ends of both end portions 85b and 85c are the inner wall portion B2a and the outer wall portion B2c of the hanging portion B2. It is elastically locked to the inner surface of the taper. The screw holding spring 85 is held in the suspending portion B2 by the engagement of both ends of the spring, and prevents the screw terminal 82 from coming off later.

  FIG. 29 shows the case where the screw terminal 82 is loosened by inserting the screwdriver 112 through the screw operation hole 111 formed in the upper plate part B2b of the hanging part B2. When this screw terminal 82 is tightened with a Phillips screwdriver 112, the washer 83 presses the screw holding portion 85a of the screw holding spring 85, the screw holding portion 85a presses the washer 84, and the washer 84 presses the outer end portion 81a of the electrode terminal plate 81. By pressing, an electrical and mechanical connection between the terminals is made. When the screw terminal 82 is loosened with the Phillips screwdriver 112, the screw terminal 82 is gradually moved up in the suspended portion B2, and the screw holding spring 85 is moved upward in accordance with the upward movement. If the loosening of the screw terminal 82 becomes excessive until just before it is detached from the electrode terminal plate 81, the screw terminal 82 may come off. At this time, the screw holding spring 85 holds the screw terminal 82 to prevent the screw terminal 82 from coming off.

  The above is the terminal mechanism 80 installed on the left hanging portion B2 in FIG. 1 of the second casing 51 and is connected to the power line side of the AC circuit. Since the terminal mechanism 80 installed in the right hanging part B3 in FIG. 1 has the same structure, the detailed description thereof is omitted. The terminal mechanism 80 of the hanging part B3 is connected to the ground line side of the AC circuit. As shown in FIGS. 23 and 24, when the three support bases SP2 are connected in parallel, one earth terminal plate 90 is attached to the three earth line side hanging portions B3 in a plug-in manner. It is done. The ground terminal plate 9 is connected to the terminal mechanism 80 of each hanging part B3 and is used as a common ground terminal for the three units.

  The ground terminal plate 90 is a band-like metal plate bent in a meandering manner as shown in FIG. 31, and is bent downward from three terminal connection portions 90a arranged in the same plane and two adjacent terminal connection portions 90a. A series of U-shaped bent portions 90b. In each of the three terminal connection portions 90a, a notch-shaped screw insertion mounting groove 91 is formed in the same direction. Corresponding to this ground terminal plate, slits 93 and 94 for ground terminal plate attachment are formed at both ends of the support base SP2. One slit 94 is formed in each of the back plate portions B2d and B3d at both ends of the second casing 51 in the horizontal direction. The other slit 93 is formed in the horizontal direction at both ends of the lid plate 52. Both the slits 93 and 94 are formed opposite to each other at a position lower than the outer end 81 a of the electrode terminal plate 81.

  As shown in FIG. 32, with the screw terminal 82 of the terminal mechanism 80 of the suspended portion B3 loosened, the bent portion 90b of the suspended portion B3 ground terminal plate 90 is inserted into the slits 93, 94, and the terminal connecting portion The mounting groove 91 of 90 a is inserted into the screw portion 82 b of the screw terminal 82. The terminal connection portion 90a is inserted up to the outer end portion 81a of the electrode terminal plate 81, and the screw terminal 82 is tightened. In this way, during the operation of attaching the ground terminal plate 90 to the support base SP2, vibration and external force from a minus driver are applied to the loosened screw terminal 82. In this case, since the screw terminal 82 is held by the screw holding spring 85, there is no fear that the screw terminal 82 will come off during the earth terminal plate mounting operation, and the mounting workability will be improved.

  Since the ground line side electrodes of the three support bases SP2 are commonly connected by one ground terminal plate 9, wiring to the ground line side of the three support bases SP2 can be performed in one process, and wiring work is easy. Become. Further, by providing the bent portion 90b between two adjacent terminal connection portions 90a of the ground terminal plate 90, the creeping distance between the adjacent terminal connection portions 90a can be increased.

  It should be noted that the power supply SPD of the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention.

FIG. 3 is a side view showing an embodiment of the present invention and includes a part of the power supply SPD that is omitted from the main body SP1 and a support base SP2 during assembly. It is a side view after the assembly of SPD of FIG. It is a side view from another direction of SPD of FIG. It is a top view of SPD of FIG. It is a right front view of SPD of FIG. It is a perspective view of the electrode extraction terminal in main body SP1 of FIG. It is a perspective view of the separation conductor in the main body SP1 of FIG. (A), (B) is a fragmentary sectional view of main part SP1. It is a perspective view of the display frame in main body SP1. It is a fragmentary sectional view of main part SP1. It is a side view explaining the state at the time of abnormality occurrence of main part SP1. It is a side view explaining the state at the time of other abnormality generation | occurrence | production of main body SP1. It is an expansion perspective view of support stand SP2. 13 is a partial perspective view of the support base SP2. (A) And (B) is the partial front view and top view of support stand SP2 of FIG. (A) And (B) is the partial front view and top view of a different state of FIG. 13 support stand SP2. (A) And (B) is the partial front view and top view of a different state of FIG. 13 support stand SP2. FIG. 18 is an enlarged cross-sectional view taken along line tt in FIG. It is a perspective view of the guide component of FIG. It is a partial exploded front view of main part SP1. It is a partial front view of main body SP1. It is a partial front view which shows the different state of main body SP1. It is a top view when three SPDs of FIG. 1 are connected. It is a front view of SPD of FIG. It is a fragmentary sectional view of SPD of FIG. It is a perspective view of the displacement interlocking member in FIG. It is a partial expanded sectional view of main body SP1 and support stand SP2 of FIG. FIG. 28 is an exploded cross-sectional view of the portion of FIG. 27. It is a partial expanded sectional view of support stand SP2 of FIG. FIG. 30 is a perspective view of the screw holding spring shown in FIG. 29. FIG. 25 is a perspective view of the ground terminal plate shown in FIG. 24. It is a partial side view at the time of earth terminal board attachment of support stand SP2 of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing | casing 2 Cover plate 10 Varistor element 11 Electrode extraction terminal 12 Insulation protective material 13 Low molten metal alloy 14 Connection auxiliary hole 21 Disconnecting conductor 21a Fixing part 21b Spring part 21c Current fuse part 21d Terminal connection part 21f Electrode terminal part 30 Display frame 32 Display window 40 Fixed guide 41 Movable guide SP1 Main body SP2 Support base

Claims (4)

A zinc oxide varistor element and a detachment having a spring force that is bonded to the electrode lead-out terminal of the varistor element with a low-melting metal alloy and is separated from the electrode lead-out terminal when the low-melting metal alloy melts due to abnormal heat generation of the varistor element. In a power supply SPD having a conductor and a housing for positioning and housing the varistor element and the separation conductor,
The separating conductor is a strip-shaped metal plate, a fixed portion that is positioned and held by the housing, a strip-shaped spring portion that is bent and extends in the plate thickness direction from the distal end side of the fixed portion, and the spring A current fuse portion that extends in a tapered shape from the tip side of the portion, and that has a cross-sectional area in which the tip portion in the extending direction is blown by a surge current exceeding the maximum surge current withstand capability of the varistor element, and its current An SPD for power supply, comprising: a terminal connection portion extending widely from a tip portion of the fuse portion and being surface-bonded to the electrode lead-out terminal via the low-melting metal alloy.   The terminal connecting portion has a plurality of positioning projections integrally in a comb-like shape at the tip portion, and the electrode lead-out terminal integrally has an engaging claw that is positioned and engaged with the plurality of positioning projections at the tip portion. The power supply SPD according to claim 1.   3. The power supply for power supply according to claim 2, wherein a connection auxiliary hole through which the low-melting metal alloy flows is formed through a plurality of locations corresponding to the plurality of positioning protrusions of the terminal connection portion in a plate thickness direction. SPD.   The power supply SPD according to any one of claims 1 to 3, wherein an electrode terminal portion protruding outside the housing is integrally formed at a rear end portion of the terminal connection portion opposite to the spring portion.

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