KR101458720B1 - Thermally fused mov device and circuitry - Google Patents

Abstract

A metal oxide varistor (MOV) device with a thermally fusible fuse is disclosed. The MOV device comprises: an MOV main body which has an MOV and an insulation sheath covering the MOV; an insulating end plate which is combined to one end of the MOV main body; a second terminal and a third terminal which are connected to the MOV within the insulation sheath; a first terminal which is extended from the top surface of the MOV main body to the outside through the insulating end plate; a fuse which connected the first terminal to the second terminal or the third terminal on the top surface of the MOV main body; an elastic member which is supported by the insulating end plate; and an insulating slider which is disposed to make one end be in contact with the elastic member and the other end be in contact with the fuse, and which is linearly moved past the fuse by elastic resilence of the elastic member to insulate the end plate from the MOV.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a MOV device which is thermally fused and a circuit including the MOV device.

FIELD OF THE INVENTION The present invention relates to a metal oxide varistor (MOV) device that thermally fuses and a circuit including the same, and more particularly, to a circuit comprising a metal oxide varistor To an MOV device and a circuit including the MOV device, which can melt and fuse together and isolate them with an insulator reliably and quickly. Further, the present invention relates to a MOV apparatus suitable for applying electrical elements such as LEDs, etc., instead of applying a mechanical element in informing the fusing of the MOV apparatus to the outside.

MOV is a type of varistor based on metal oxides, especially zinc oxide (ZnO). MOV has a nonlinear current-voltage characteristic, which depends on the doping of dopant in the metal oxide grains.

The current-voltage curves of the MOV are generally divided into a leakage current region, a breakdown area, and a large current area. When connected in parallel with the load and operating in the leakage current region, the MOV exhibits very high resistance and very small current characteristics. However, if there is a sudden voltage surge due to, for example, a power supply abnormality, the voltage may suddenly increase.

At this time, if the voltage exceeds the predetermined voltage, the ratio between the current and the voltage increases nonlinearly. In this situation, the resistance of the varistor can drop the resistance of several ohms. In this way, the MOV increases the current conduction, thereby eliminating the excess voltage, thereby protecting the electronic circuitry.

As described above, MOVs, in particular, zinc oxide based MOVs have excellent protection characteristics against excessive surges, but do not have protection characteristics against overheating associated with excessive surges.

On the other hand, a MOV device having a fuse that is thermally fused has been developed. Such a MOV device has a thermal protection characteristic and is referred to as a TMOV device. TMOV devices have been developed in two forms, one of which is a clothed type embedded in a case and the other is a bared type which is exposed to the outside without a case.

A bare type TMOV device includes a structure in which a terminal is connected to a temperature sensitive fuse, which terminal extends to the outside. This TMOV device is disadvantageous in that the terminal is separated from the MOV only when the fuse is completely melted by the heat conducted to the terminal end, so that the reaction speed is slow and reliable separation is difficult.

In addition, the Claude type TMOV device includes an additional "A" type terminal connected to the MOV main body by soldering with one end fixed in the case, a rotatable insulating trigger in the case, and a spring for biasing the trigger in the rotating direction.

When the temperature of the MOV main body rises above a certain temperature, the fuse starts to melt, and the fusing force of the fuse becomes smaller than the deflection rotational force of the trigger, so that the trigger rotates to separate the "A" type terminal from the MOV main body.

In addition, the case has an opening for visually exposing the mark formed on the trigger after the rotation of the trigger is completed. The user or the operator can check the abnormal state due to overheating by viewing the mark exposed through the opening.

However, this Claude type TMOV device has a complicated structure and is better than the Baer type, but has a disadvantage that the reliability is not high. Moreover, there is a disadvantage that the user or the operator must check the marker at a short distance in a manner that informs the abnormal state in a mechanical manner.

Korean Patent Publication No. 10-2009-0131358 (December 29, 2009)

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a thermally fused MOV device capable of fusing on a MOV body when the heat rushes, melting and fusing the heat on the MOV main body and isolating the fuse on the MOV body reliably and quickly with an insulator .

Another object of the present invention is to provide a circuit capable of informing an abnormal state due to overheating by using an LED operating in accordance with thermal fusing of a MOV apparatus.

There is provided a MOV device having a fuse thermally fused in accordance with an aspect of the present invention, the MOV device comprising: an MOV body having an MOV and an insulating sheath surrounding the MOV; An insulating end plate coupled to one end of the MOV body; A second terminal and a third terminal connected to the MOV in the insulating sheath; A first terminal extending from the upper surface side of the MOV main body to the outside through the insulating end plate; A fuse connecting the first terminal to the second terminal or the third terminal on an upper surface of the MOV main body; An elastic member supported by the insulating end plate; The first terminal is arranged to be in contact with the elastic member and the other end so as to be in contact with the fuse, and when the fuse is fused, the first terminal is insulated from the MOV by linear movement through the fuse by elastic restoring force of the elastic member And an insulating slider.

According to one embodiment, the insulation slider includes a guide groove loosely received on the upper surface thereof so that the first terminal can be slid along the first terminal when the fuse is fused and the elastic member is elastically restored .

According to one embodiment, the fuse is comprised of a solder.

According to one embodiment, the second terminal and the third terminal extend through the end plate and extend in parallel to the first terminal, and the elastic member is elastically compressed to be fitted to a pair of projections formed on the insulation slider Wherein the first terminal has a bent portion in the vicinity of an end portion connected to the fuse.

According to another aspect of the present invention, there is provided a protection circuit to which the aforementioned MOV device is applied and which is connected in parallel with the circuit to be protected. The protection circuit comprising: a first current path; A second current path along the fuse and the MOV; And a third current path following the warning LED. In a steady state, a current flows to the first current path and the circuit to be protected, and when a surge voltage is applied, a current due to the surge voltage flows to the second current path to protect the circuit to be protected, When the fuse is fused and the insulation slider insulates the first terminal, current flows to the third current path to light the warning light.

According to one embodiment, in the second current path, the second terminal and the third terminal are connected to the contacts of the MOV and the second terminal is connected to the first terminal by the fuse, The first current path includes a resistor R1 and a green LED, and the third current path includes a warning LED and a resistor R2, and the warning LED may be a red LED.

The MOV device according to the present invention can prevent the damage of the circuit to be protected due to the continuation of the overheating by fusing the fuses connecting the terminals of the varistor when the heat rushes, . According to the present invention, the operation of the insulation slider can be made only by the resilient restoring force of the elastic member supported on the end plate coupled to the MOV main body. This is because the conventional case has a case accommodating the MOV main body and a complicated mechanism . ≪ / RTI > Further, since the present invention informs the abnormal state of the MOV due to the overheating by the warning LED, in particular, the red LED. It makes it easier and quicker for the operator or user to cope with the MOV device than the MOV device which informs the mechanism abnormality of the MOV.

1 is a perspective view illustrating an MOV apparatus according to an embodiment of the present invention.
Fig. 2 is an enlarged perspective view of "A" in Fig. 1. Fig.
FIGS. 3A and 3B are cross-sectional views illustrating a fusing action according to overheating of a MOV device according to an embodiment of the present invention.
4 is a cross-sectional view showing a state in which a MOV device according to an embodiment of the present invention is coupled to a PCB (Printed Circuit Board).
5 is a circuit diagram illustrating a circuit to which a MOV device according to an embodiment of the present invention is applied.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided as examples for allowing a person skilled in the art to sufficiently convey the idea of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms.

FIG. 1 is a perspective view showing an MOV apparatus according to an embodiment of the present invention, FIG. 2 is an enlarged perspective view of FIG. 1, and FIG. 3a and FIG. FIG. 4 is a cross-sectional view illustrating a state in which a MOV device according to an embodiment of the present invention is coupled to a PCB (Printed Circuit Board). FIG. 5 is a cross- Is a circuit diagram for explaining a circuit to which a MOV device according to an embodiment of the present invention is applied.

1, a MOV apparatus 1 according to an embodiment of the present invention includes a MOV body 10, an end plate 20, first and second And a third terminal 30, 40, 50, a fuse 60, an insulation slider 70, and a pair of springs 80, 80.

The MOV body 10 includes an insulating coating that surrounds the outside of a metal oxide varistor and a metal oxide varistor (hereinafter referred to as MOV). The end plate 20 is made of an insulating material and is joined to the end of the MOV main body 10.

The second terminal 40 and the third terminal 50 are connected to corresponding contacts of the MOV in the insulation jacket of the MOV main body 10 and are drawn out of the insulation jacket so as to pass through the end plate 20, . In this case, the second terminal 40 and the third terminal 50 may extend outside the end plate 20 in parallel with the first terminal 30.

The first terminal 30 is a terminal to which the fuse 60 is connected and is connected to the second terminal 40 or the third terminal 50 via the fuse 60 on the upper surface side of the MOV main body 10. [ Lt; / RTI > At this time, a gap exists between the first terminal 30 and the upper surface of the MOV main body 10, except for the terminal bent portion 32 of the first terminal 30 connected to the fuse 60.

The first terminal 30 extends rearward from the end portion connected to the fuse 60 and protrudes from the upper surface of the MOV main body 10 through the end plate 20.

The fuse 60 is formed of a solder material (or a soldering material) that melts at a predetermined temperature or more during thermal runaway. The first terminal 30, that is, the fuse connecting terminal 30, To the exposed second or third terminal (40 or 50).

1 and 2, the insulating slider 70 has an elongated shape and is positioned between the upper surface of the MOV main body 10 and the first terminal 30. As shown in FIG. One end of the insulation slider 70 is in contact with a pair of springs 80 and 80 provided on the end plate 20 and the other end of the insulation slider 70 faces the fuse 60 have.

In this state, the pair of springs 80 and 80 are resiliently compressed, and therefore, the deflection force to push the insulation slider 70 against the fuse 60 is continuously provided . It should be noted that in this embodiment a compression spring is used, but other types of springs or other resilient members can be used if the insulation slider 70 can provide a biasing force.

The insulating slider 70 may be slidable along the first terminal 30 when the fuse 60 is melted and the pair of springs 80 and 80 are elastically restored. And the upper surface includes a guide groove 72 in which the terminal 30 is loosely received.

The insulation slider 70 has a proximal end portion that is in contact with the springs 80 and 80 so that the insulation slider 70 can be elastically supported by the springs 80 and 80 relatively stably. A pair of protrusions 82 and 82 is formed at the proximal end of the insulating slider 70 so that a pair of the springs 80 and 80 are inserted.

Referring to FIGS. 3A and 3B, the fusing action of the MOV device according to the present embodiment will be described as follows.

First, in the steady state shown in FIG. 3A, the first terminal 30 is fixedly connected to the fuse 60 on the upper surface side of the MOV main body 10. Further, the insulating slider 70 is positioned below the first terminal 30 and is blocked by the fuse 60 at one end. At this time, the insulator slider 70 receives a linear biasing force in the pushing direction of the fuse 60 by the compressed springs 80 and 80 (see Figs. 1 and 2) elastically supporting the insulator slider 70 itself.

Next, in the overheated state shown in FIG. 3B, the solder constituting the fuse 60 melts and the bonding force to the first terminal 30 weakens, and the bonding force becomes smaller than the biasing force applied to the insulating slider 70 . At this time, the insulating slider 70 linearly moves due to the resilient restoring force of the spring 80, and is located between the first terminal 30 and the MOV main body 10. As a result, the first terminal 30 and the MOV main body 10 ) MOV is reliably insulated by the insulation slider (70). At this time, the solder material constituting the fuse 60 is melted by overheating due to the overvoltage, and the temperature at which the solder material is melted can be predetermined according to the circuit characteristics.

As described above, in the MOV apparatus according to the present embodiment, a fuse connecting the terminals of the MOV is fused when the heat is runaway, and at the same time, the insulating slider insulates the terminal connected portion with a quick response, Thereby preventing damage to the circuit to be protected. According to the present embodiment, the operation of the insulation slider can be made only by the resilient restoring force of the spring supported on the end plate 20 coupled to one end of the MOV main body 10, And the elimination of complex mechanisms installed in the case.

FIG. 4 shows a state where the MOV apparatus 1 according to the embodiment of the present invention is coupled to a PCB (Printed Circuit Board) 2. The first terminal 30, the second terminal 40 and the third terminal 50 of the MOV apparatus 1 are connected to the first terminal connection hole 5a and the second terminal connection hole 5b of the PCB 5, And the third terminal connection hole 5c, respectively, and is applied to the circuit in the PCB 5.

FIG. 5 shows an example of a protection circuit to which the above-described MOV device is thermally fused.

5, the protection circuit includes a first current path along the resistor R1 and the green LED 2, a second current path along the fuse 60 and the metal oxide varistor MOV 11, And a third current path following the LED 3 and the resistor R2. At this time, the protection circuit is connected in parallel with the circuit to be protected. The second terminal 40 and the third terminal 50 are connected to the contacts of the MOV 11 and the second terminal 40 is connected to the fuse 60 (Not shown).

In the normal state (i.e., steady state), the current flows to the first pass and the protected circuit along the resistor R1 and the green LED. At this time, the green LED 2 indicates that the power is on. On the other hand, when a surge voltage is externally applied, the current due to the surge voltage flows to the second current path following the MOV 11 to protect the circuit to be protected. The fuse 60 is fused (that is, the solder is melted) due to overheating due to the abnormal state of the MOV 11 and the first terminal 30 is disconnected from the MOV 11 by the insulation slider 70 If it is insulated, a current flows through the third current path following the red LED 3 and the resistor R2, and the red LED 3 is turned on to notify the abnormal state of the MOV 11.

As described above, the present invention informs the red LED 3 of an abnormal state of the MOV 11 due to overheating. It makes it easier and quicker for the operator or user to cope with the MOV device than the MOV device which informs the mechanism abnormality of the MOV.

1: MOV device 10: MOV main body
11: MOV 20: End plate
30: first terminal 40: second terminal
50: third terminal 60: fuse
70: Insulation slider 72: Guide groove
80: Spring 5: PCB
5a, 5b, 5c: Terminal connection holes

Claims (5)

An MOV body having an MOV and an insulating sheath surrounding the MOV; An insulating end plate coupled to one end of the MOV main body; A second terminal and a third terminal connected to the MOV in the insulating sheath; A first terminal extending from the upper surface side of the MOV main body to the outside through the insulating end plate; And a fuse connecting the first terminal to the second terminal or the third terminal on an upper surface of the MOV main body,
Wherein the first terminal has a terminal bend in the vicinity of an end portion connected to the fuse,
A gap exists between the first terminal and the upper surface of the MOV main body, except for a terminal bent portion of the first terminal connected to the fuse,
Further comprising an elastic member whose one end is supported by the insulating end plate in a compressed state,
Further comprising an insulating slider disposed in the gap with one end thereof abutting against the elastic member and the other end abutting against the fuse in a state in which the fuse is not fused,
When the fuse is fused and the elastic member is released from the compression state, the insulation slider is linearly moved by the resilient restoring force of the elastic member so that the other end passes through the fuse, and the first terminal is insulated from the MOV The MOV device comprising: The insulator slider according to claim 1, wherein the insulator slider includes a guide groove loosely received in the first terminal so that the insulator slides along the first terminal when the fuse is fused and the elastic member is resiliently restored Featured MOV devices. The connector according to claim 1, wherein the second terminal and the third terminal extend through the end plate and extend in parallel with the first terminal, and the elastic member is elastically compressed by an elastic compression spring And the MOV device. A protection circuit to which a MOV device according to any one of claims 1 to 3 is applied and which is connected in parallel with a circuit to be protected,
A first current path;
A second current path along the fuse and the MOV; And
And a third current path following the warning LED,
In steady state, current flows into the first current path and the circuit to be protected,
When a surge voltage is applied, a current due to the surge voltage flows to the second current path to protect the protected circuit,
Wherein when the fuse is fused due to overheating and the insulation slider insulates the first terminal, a current flows into the third current path to light the warning LED. The method of claim 4, wherein in the second current path, the second terminal and the third terminal are connected to the contacts of the MOV and the second terminal is connected to the first terminal by the fuse, Wherein the first current path includes a resistor R1 and a green LED, the third current path includes a warning LED and a resistor R2, and the warning LED is a red LED.

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