JP7197887B2 - lightning arrestor - Google Patents

Description

The present invention comprises a varistor that absorbs surges such as induced lightning, a thermal fuse that operates by heat generated when the varistor fails, an exterior case that houses the varistor and the thermal fuse, and a seal filled in the exterior case. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightning arrester provided with an anti-resin, and more particularly to a lightning arrester capable of externally detecting a failure state of the lightning arrester with a simple configuration that does not use electrical means.

2. Description of the Related Art Conventionally, lightning arresters have been used to protect electronic devices by absorbing surges such as induced lightning that enter electronic devices through power lines and the like.
Such surge arresters use varistors, which are high resistance elements with nonlinear voltage characteristics, as electronic components that absorb surges.

By the way, the IEC standard (IEC61643-11), which is an international standard for this lightning arrester, requires separation of the varistor from the power supply circuit and provision of a "mechanism for displaying the failure state" in the event of a failure.

Therefore, the present applicant previously proposed a lightning arrester according to Japanese Patent Application Laid-Open No. 2018-10906 (Patent Document 1).
The lightning arrester of Patent Document 1 described above "includes first to third varistors, first and second fuse members, and an exterior case for housing the above-mentioned varistors and fuse members. A first fuse member, a first varistor, a second varistor and a second fuse member are sequentially arranged therebetween. A lightning arrester in which a varistor and a third varistor are sequentially arranged, and further, a second fuse member, a second varistor, and a third varistor are sequentially arranged between a neutral line and a ground line of an AC power supply, A lightning arrester characterized in that an irreversible temperature indicating material that changes color due to heat generated when the second varistor and the third varistor fail is provided on the outer surface of the exterior case.

In the lightning arrester of Patent Document 1, an irreversible temperature indicating material that changes color due to heat generated when the second varistor and the third varistor fail is provided on the outer surface of the exterior case. By visually recognizing the color, the failure state of the lightning arrester can be detected with a simple configuration that does not use electrical means.

Japanese Patent Application Laid-Open No. 2018-10906

By the way, the lightning arrester may be used in an outdoor environment or in a dusty factory environment. and is not adversely affected by strong direct jets of water from any direction). It is necessary to seal electronic parts such as fuses and fuse members.

However, when the exterior case is filled with resin to seal the varistor, the heat generated by the varistor at the time of failure diffuses into the sealing resin, so the heat is not sufficiently transmitted to the temperature indicator material on the outer surface of the exterior case. As a result, even though the varistor is out of order, the color of the temperature indicating material does not change, and there is a possibility that the failure cannot be detected.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a lightning arrester having a simple structure that does not use electrical means, and a lightning arrester that is formed by filling a sealing resin in an exterior case. An object of the present invention is to realize a lightning arrester capable of detecting a failure state.

In order to achieve the above object, the lightning arrester according to claim 1 of the present invention comprises:
A main body comprising an insulating substrate mounted with a varistor and a thermal fuse operated by heat generated when the varistor fails, a transparent cover member covering the varistor and the thermal fuse of the main body, and the main body and the cover member are accommodated. and a lightning arrester comprising a sealing resin filled in the exterior case,
An irreversible temperature indicating material that changes color due to heat generated when the varistor fails is provided on the surface of the varistor and/or the thermal fuse, and
The lid member is provided with an externally exposed portion that is exposed to the outside from the sealing resin, and
The temperature indicating material is configured to be visible from the externally exposed portion of the lid member.

The lightning arrester according to claim 2 of the present invention is the lightning arrester according to claim 1,
The thermal fuse is a rectangular thermal fuse, and the temperature indicating material is provided on the surface of the rectangular thermal fuse.

The lightning arrester according to claim 3 according to the present invention is the lightning arrester according to claim 1 or 2,
The externally exposed portion is a protrusion projecting from the lid member.

The lightning arrester according to claim 4 of the present invention is the lightning arrester according to any one of claims 1 to 3,
A plurality of varistors arranged between a plurality of power supply terminals connected to the power supply line of an AC power supply and a ground terminal, and a relatively high temperature operation in which power supply to the varistors is interrupted by heat generated when the varistors fail. and a relatively low-temperature operating thermal fuse disposed between a pair of contacts not connected to the power supply line of the AC power supply and operated by heat generated when the varistor fails are mounted on the insulating substrate. It is characterized by

The lightning arrester according to claim 5 of the present invention is the lightning arrester according to claim 4,
The operating temperature of the relatively high temperature operating thermal fuse is 147.degree. C., and the operating temperature of the relatively low temperature operating thermal fuse is 115.degree.

In the lightning arrester according to claim 1 of the present invention, an irreversible temperature indicating material that changes color due to heat generated when the varistor fails is provided on the surface of the varistor and/or the thermal fuse, and is mounted on the insulating substrate. The varistor and the thermal fuse are covered with a transparent lid member, and further, an externally exposed portion exposed from the sealing resin is provided so that the temperature indicating material can be visually recognized from the externally exposed portion. The heat generated by the varistor at the time of failure can be transmitted to the temperature indicating material without using electric means, and the color change of the temperature indicating material can be visually recognized through the externally exposed portion of the transparent lid member, with a simple configuration. A fault condition can be detected from the outside of the lightning arrester.

As described in claim 2, a rectangular thermal fuse is used as the thermal fuse, and a temperature indicating material is provided on the surface of the rectangular thermal fuse from the viewpoint of ease of application of the temperature indicating material and an increase in the formation area of the temperature indicating material. preferable.

In the lightning arrester according to claim 4 of the present invention, in addition to the temperature indicating material of the non-electrical means, a thermal fuse is connected between a pair of contacts for sending a failure signal of the varistor to the outside, and a thermal fuse is connected between the contacts. Since the power supply is not performed from the AC power supply, for example, power can be supplied between the contacts from an external power supply such as a DC power supply, or the insulation resistance of the contacts that are normally closed and abnormally open can be measured using a tester, etc. By measuring , it is possible to detect the failure state of the lightning arrester even with a simple "electrical means".

In addition, since a relatively low-temperature operating thermal fuse is placed between the pair of contacts and is operated by the heat generated when the varistor fails, if the varistor fails and the temperature rises, the relatively low-temperature operating thermal fuse placed between the contacts is used. Since the thermal fuse of this type is fused and separated earlier than the thermal fuse of the relatively high temperature operating type, it is possible to reliably output a failure signal early.

A lightning arrester according to the present invention will be described below with reference to the accompanying drawings.
1 is a perspective view showing a lightning arrester 10 according to the present invention, FIG. 2 is a plan view of the same, FIG. 3 is a perspective view showing a main body 12 of the lightning arrester 10 according to the present invention, FIG. 4 is the same plan view, and FIG. 1 is a circuit configuration diagram of a lightning arrester 10 according to the present invention; FIG.

The lightning arrester 10 of the present invention comprises a box-shaped exterior case 14 (FIGS. 1 and 2) made of an insulating material such as resin, an insulating substrate 16 made of resin or the like, and the insulating material, as shown in FIGS. Four substantially disc-shaped varistors (first varistor 18, second varistor 20, third varistor 22, and fourth varistor 24) mounted on substrate 16 and three substantially cylindrical varistors. round thermal fuses (first round thermal fuse 26, second round thermal fuse 28, third round thermal fuse 30) and two rectangular thermal fuses formed in a substantially prismatic shape. (first square thermal fuse 32, second square thermal fuse 34), one gas arrester 36, main body 12 housed in exterior case 14, and inside exterior case 14 A sealing resin 38 made of an insulating resin such as epoxy is filled in the outer case 14 and seals the opening of the outer case 14 .

1 to 4, 40, 42, and 44 are first to third power terminals respectively connected to power lines 1 to 3 (see FIG. 5) of the AC power supply, and 46 is connected to the ground (G). A connected ground terminal 48 is a contact signal line connected to contacts R1 and R2 (see FIG. 5).

As shown in the circuit diagram of FIG. 5, a first round thermal fuse 26, a first varistor 18, a second varistor 20, a second Round thermal fuses 28 are arranged in sequence.
A first round thermal fuse 26, a first varistor 18, a third varistor 22, and a third round thermal fuse 30 are sequentially arranged between the first power terminal 40 and the third power terminal 44. there is
A second round thermal fuse 28, a second varistor 20, a third varistor 22, and a third round thermal fuse 30 are sequentially arranged between the second power terminal 42 and the third power terminal 44. there is
A first round thermal fuse 26, a first varistor 18, a fourth varistor 24, and a gas arrester 36 are sequentially arranged between the first power supply terminal 40 and the ground terminal 46. As shown in FIG.
A second round thermal fuse 28, a second varistor 20, a fourth varistor 24, and a gas arrester 36 are arranged in this order between the second power terminal 42 and the ground terminal 46. As shown in FIG.
A third round thermal fuse 30, a third varistor 22, a fourth varistor 24, and a gas arrester 36 are arranged in order between the third power supply terminal 44 and the ground terminal 46. As shown in FIG.

A first rectangular thermal fuse 32 and a second rectangular thermal fuse 34 are connected between the contact R1 and the contact R2 connected via the contact signal line 48 .
The contacts R1 and R2 are not connected to the power supply lines 1, 2, and 3. Therefore, the power supply between the contacts R1 and R2 is not performed from an AC power source. It is connected to an external power supply and supplied with power from an external power supply such as DC24V.

The first varistor 18 to the fourth varistor 24 are electronic components having voltage non-linear resistance characteristics in which the resistance sharply decreases as the applied voltage rises. , the resistance decreases abruptly, so that the current is instantaneously (approximately 10 ⁻⁹ seconds) to absorb the surge.

On the other hand, varistors (the first varistor 18 to the fourth varistor 24) have the drawback of having a small current withstand capability, so an abnormal overvoltage that exceeds the rating is applied to the varistors, causing continuous overcurrent to flow and causing failure. When reaching , there is a risk of heat generation and an abnormally high temperature state (for example, 1000° C. or higher), which may cause fire or burnout.
The above-mentioned first round thermal fuse 26 to third round thermal fuse 30 are overheat protections that cut off the power supply to the varistor by fusing and separating when the surrounding temperature rises due to the heat generated by the varistor and reaches a predetermined temperature. It is a part.

In this embodiment, the operating temperature of the first square thermal fuse 32 and the second square thermal fuse 34 connected between the pair of contacts R1 and R2 is the same as that of the first round thermal fuse 26. ∼ the third round thermal fuse 30 is set to operate at a temperature lower than that of the thermal fuse, and the first round thermal fuse 26 to the third round thermal fuse 30 have a relatively high temperature. It is configured as an operational thermal fuse.
Specifically, the operating temperature at which the relatively low-temperature operating first square thermal fuse 32 and the second square thermal fuse 34 are fused and separated is 115° C., and the comparatively high-temperature operating first round thermal fuse 32 is 115° C. The operating temperature at which the fuse 26 to the third round thermal fuse 30 melt and separate is 147°C.

The gas arrester 36 is an electronic component comprising a plurality of discharge electrodes arranged with discharge gaps and a discharge gas enclosed in an airtight envelope. , a discharge is generated in the discharge gap to absorb the surge.

As shown in FIGS. 3 and 4, an irreversible temperature indicating material 50 whose color changes when a set temperature is reached is placed on the upper surfaces of the first rectangular thermal fuse 32 and the second rectangular thermal fuse 34. are provided.
The temperature indicating material 50 is a temperature detecting material using a temperature indicating pigment or the like that undergoes a chemical reaction such as thermal decomposition and changes color when it reaches a set temperature. An "irreversible" temperature indicating material 50 is used that does not return to the original color even if it descends and maintains the changed color.
In this embodiment, the temperature indicating material 50 is formed by applying a temperature indicating material made of paint. may be attached to the upper surface of the rectangular thermal fuse 34.

The change temperature of the temperature indicating material 50 of this embodiment is set to 90°C, and normally it is "white", but when it reaches the change temperature of 90°C, it changes color to "red".

As shown in FIGS. 3 and 4, the first rectangular thermal fuse 32 is arranged in contact with the first varistor 18 and the second varistor 20, so that the first varistor 18 and the second varistor 20 When the first rectangular thermal fuse 32 reaches the changing temperature (90°C) due to the heat generated at the time of failure, the temperature indicating material 50 changes from white to red, and when it reaches the operating temperature (115°C), the first rectangular thermal fuse 32 changes from white to red. Thermal fuse 32 is blown and separated.
Since the second rectangular thermal fuse 34 is arranged in contact with the third varistor 22 and the fourth varistor 24, heat generated when the third varistor 22 and the fourth varistor 24 fail causes the second When the rectangular thermal fuse 34 reaches the changing temperature (90° C.), the temperature indicating material 50 changes from white to red, and when it reaches the operating temperature (115° C.), the second rectangular thermal fuse 34 is fused and separated.

Also, since the first round thermal fuse 26 is arranged in contact with the first varistor 18, it is fused and separated when the operating temperature (147° C.) is reached due to heat generated when the first varistor 18 fails. block the
The second round thermal fuse 28 is arranged in contact with the second varistor 20, so that when the second varistor 20 fails, heat is generated, and when the operating temperature (147°C) is reached, the second round thermal fuse 28 is fused and separated to cut off the power supply. do.
The third round thermal fuse 30 is arranged in contact with the third varistor 22, so that when the third varistor 22 fails, the heat generated by the third varistor 22 reaches the operating temperature (147°C). do.

In FIG. 6, reference numeral 52 denotes a transparent cover member made of an insulating material such as polycarbonate resin. The cover member 52 has a substantially rectangular parallelepiped shape with an open bottom and protrudes upward from its upper surface 52a. It has two protrusions 54 .
The lid member 52 is used by covering the insulating substrate 16, and includes four varistors (first varistor 18 to fourth varistor 24) and three round varistors arranged on the insulating substrate 16. Covering thermal fuses (first round thermal fuse 26 to third round thermal fuse 30) and two square thermal fuses (first square thermal fuse 32 and second square thermal fuse 34) member (see FIGS. 7 and 8).

Since the cover member 52 is transparent, when the varistor, the round thermal fuse, and the square thermal fuse are covered, the varistor, the round thermal fuse, and the square thermal fuse can be visually recognized from the outside.
The protrusion 54 of the lid member 52 faces the temperature indicating material 50 provided on the upper surface of the first square thermal fuse 32 and the second square thermal fuse 34 when the lid member 52 is placed over the insulating substrate 16. As a result, as shown in FIG. 8, the temperature indicating material 50 can be seen from the outside through the protrusion 54.

As shown in FIGS. 9 and 10, the main body 12 in which the varistor, the round thermal fuse, and the square thermal fuse are covered with the cover member 52 is housed in the external case 14. As shown in FIGS. In this state, one ends of the power terminals 40, 42, 44, the ground terminal 46, and the contact signal lines 48, 48 are led out of the exterior case 14. As shown in FIG.
After that, the exterior case 14 is filled with the sealing resin 38 to complete the surge arrester 10 shown in FIG.
Incidentally, as shown in FIG. 1, the protrusion 54 of the lid member 52 is exposed to the outside of the sealing resin 38 and constitutes an externally exposed portion.

In the lightning arrester 10 of the present invention, since the varistor voltage (two pieces)>power supply voltage>varistor voltage (one piece), any one of the power supply lines 1-2, 1-3, and 2-3 When a surge is applied to and any one of the first varistor 18, second varistor 20, and third varistor 22 breaks down and becomes a high temperature state, the other varistors will also operate at the power supply voltage. Fever.

When the temperature of the first square thermal fuse 32 and the second square thermal fuse 34 reaches 90° C. due to the heat generated by the varistor, the upper surfaces of the first square thermal fuse 32 and the second square thermal fuse 34 are formed. The white temperature indicating material 50 changes to red.
As described above, since the projecting portion 54 of the transparent lid member 52 is exposed to the outside of the sealing resin 38, the temperature indicating material 50 in the white state before the change (see FIG. 11) and the temperature indicating material in the red state after the change 50 (see FIG. 12) is visible from the exterior of the arrestor 10. FIG.

Further, when the temperature of the first rectangular thermal fuse 32 and the second rectangular thermal fuse 34 connected between the pair of contacts R1 and R2, which operate at a relatively low temperature, reaches 115° C. due to the heat generated by the varistor, the second One rectangular thermal fuse 32 and a second rectangular thermal fuse 34 are blown and separated.

After that, when the temperature of the first round thermal fuse 26 to the third round thermal fuse 30, which operate at a relatively high temperature, reaches 147° C. due to the heat generated by the varistor, the first round thermal fuse 26 to the third round thermal fuse 26 The type thermal fuse 30 is fused and separated to cut off the power supply.

Similarly, if a surge is applied between the power supply lines 1, 2, 3-G and any one of the first varistor 18, second varistor 20, and third varistor 22 fails and becomes hot, the other varistors also generate heat.
As a result, when the temperature of the first square thermal fuse 32 and the second square thermal fuse 34 reaches 90° C. due to the heat generated by the varistor, the first square thermal fuse 32 and the second square thermal fuse 34 The white temperature indicating material 50 formed on the upper surface changes to red.
Further, when the temperature of the first rectangular thermal fuse 32 and the second rectangular thermal fuse 34 connected between the pair of contacts R1 and R2, which operate at a relatively low temperature, reaches 115° C. due to the heat generated by the varistor, the second One rectangular thermal fuse 32 and a second rectangular thermal fuse 34 are blown and separated.
Furthermore, when the temperature of the first round thermal fuse 26 to the third round thermal fuse 30, which operate at a relatively high temperature, reaches 147° C. due to the heat generated by the varistor, the first round thermal fuse 26 to the third round thermal fuse 26 The type thermal fuse 30 is fused and separated to cut off the power supply.

In the lightning arrester 10 of the present invention, the temperature indicating material 50 is provided on the upper surface of the square thermal fuse (the first square thermal fuse 32 and the second square thermal fuse 34), and the varistor ( (first varistor 18 to fourth varistor 24) and thermal fuses (first square thermal fuse 32 and second square thermal fuse 34, first round thermal fuse 26 to third round thermal fuse 30) is covered with a transparent lid member 52, and the temperature indicating material 50 is visible from the outside through the protrusion 54 of the lid member 52 exposed from the sealing resin 38. The heat generated when the varistor fails can be transmitted to the temperature indicating material 50 without using electrical means, and the color change of the temperature indicating material 50 can be visually recognized through the protrusion 54 of the transparent lid member 52. A failure state of the lightning arrester 10 can be detected from outside the case 14 .

Further, in the lightning arrester 10 of the present invention, in addition to the temperature indicating material 50 which is a non-electrical means, a first square thermal fuse 32 and a No. 2 rectangular thermal fuse 34 is connected, and the power supply between the contacts R1 and R2 is supplied from an external power source other than an AC power source. A fault condition can also be detected by electrical means.

In addition to the supply of power from an external power supply to the pair of contacts R1 and R2, for example, the insulation resistance of the contacts R1 and R2, which are normally closed and abnormally opened, can be measured with a tester or the like. , the failure state of the lightning arrester 10 can be detected by electrical means with a simple configuration.

The first square thermal fuse 32 and the second square thermal fuse 34 connected between the contact R1 and the contact R2 have operating temperatures corresponding to the first round thermal fuse 26 to the third round thermal fuse 26 to the third round thermal fuse 26. Since the thermal fuse operates at a relatively low temperature, which is lower than the operating temperature of the thermal fuse 30, when the varistors (the first varistor 18 to the fourth varistor 24) fail and the temperature rises, the contact R1-contact R2 A first square thermal fuse 32 and a second square thermal fuse 34 operating at a relatively low temperature are connected to other thermal fuses operating at a relatively high temperature (the first round thermal fuse 26 to the third thermal fuse 26). Since the thermal fuse 30) is fused and separated before the round thermal fuse 30), it is possible to reliably output a failure signal early.

It should be noted that the present invention is not limited to the above embodiments, and can be modified in various forms without changing the gist of the invention.
For example, in the above embodiment, a square thermal fuse is used and the temperature indicating material 50 is provided on the upper surface of the square thermal fuse from the viewpoint of ease of application of the temperature indicating material and an increase in the formation area of the temperature indicating material 50. A temperature indicating material 50 may be provided on the upper surface of the type thermal fuse.
Further, in the above embodiment, the temperature indicating material 50 is provided on the "upper surface" of the rectangular thermal fuse, but the present invention is not limited to this, and the temperature indicating material 50 is provided on the "surface" of the rectangular thermal fuse. It is sufficient that the temperature indicating material 50 provided on the surface can be visually recognized from the outside through the protrusion 54 of the transparent lid member 52 .
Furthermore, in the above embodiment, the thermal fuses (the first rectangular thermal fuse 32 and the second rectangular thermal fuse 34) are provided with the temperature indicating material 50. and the varistor may be provided with the temperature indicating material 50 .

1 is a perspective view showing a lightning arrester according to the present invention; FIG. 1 is a plan view showing a lightning arrester according to the present invention; FIG. 1 is a perspective view showing a main body of a lightning arrester according to the present invention; FIG. FIG. 2 is a plan view showing the main body of the lightning arrester according to the present invention; 1 is a circuit configuration diagram of a lightning arrester according to the present invention; FIG. It is a perspective explanatory view showing the manufacturing process of the lightning arrester according to the present invention. FIG. 4 is a perspective view showing a state in which the varistor and the thermal fuse are covered with a cover member; FIG. 4 is a plan view showing a state in which the varistor and the thermal fuse are covered with a cover member; It is a perspective explanatory view showing the manufacturing process of the lightning arrester according to the present invention. It is a perspective explanatory view showing the manufacturing process of the lightning arrester according to the present invention. FIG. 4 is an explanatory diagram showing a state in which the temperature indicating material applied to the thermal fuse is viewed from the outside of the exterior case; FIG. 4 is an explanatory diagram showing a state in which the temperature indicating material applied to the thermal fuse is viewed from the outside of the exterior case;

10 lightning arrestor
12 Body
14 Exterior case
16 insulating substrate
18 1st Varistor
20 Second barista
22 The third barista
24 Fourth Barista
26 1st round thermal fuse
28 Second round thermal fuse
30 Third round thermal fuse
32 First square thermal fuse
34 Second rectangular thermal fuse
36 gas arrester
38 Sealing resin
40 First power supply terminal
42 Second power terminal
44 Third power terminal
46 Ground terminal
48 Contact signal line
50 temperature indicator
52 Lid member
52a Upper surface of lid member
54 Projection

Claims (5)

A main body comprising an insulating substrate mounted with a varistor and a thermal fuse operated by heat generated when the varistor fails, a transparent cover member covering the varistor and the thermal fuse of the main body, and the main body and the cover member are accommodated. and a lightning arrester comprising a sealing resin filled in the exterior case,
An irreversible temperature indicating material that changes color due to heat generated when the varistor fails is provided on the surface of the varistor and/or the thermal fuse, and
The lid member is provided with an externally exposed portion that is exposed to the outside from the sealing resin, and
A lightning arrester, wherein the temperature indicating material is visible from the externally exposed portion of the lid member. 2. A lightning arrester according to claim 1, wherein said thermal fuse is a square thermal fuse, and said temperature indicating material is provided on the surface of said square thermal fuse. 3. A lightning arrester according to claim 1, wherein said externally exposed portion is a projecting portion projecting from said cover member. A plurality of varistors arranged between a plurality of power supply terminals connected to the power supply line of an AC power supply and a ground terminal, and a relatively high temperature operation in which power supply to the varistors is interrupted by heat generated when the varistors fail. and a relatively low-temperature operating thermal fuse disposed between a pair of contacts not connected to the power supply line of the AC power supply and operated by heat generated when the varistor fails are mounted on the insulating substrate. A lightning arrester according to any one of claims 1 to 3, characterized in that 5. A lightning arrester according to claim 4, wherein the operating temperature of said relatively high temperature operating thermal fuse is 147[deg.] C. and the operating temperature of said relatively low temperature operating thermal fuse is 115[deg.] C.

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