External thermal tripping device for discharge gap

Abstract

The utility model relates to a thermal tripping device with an external discharge gap, which comprises two electrodes which are kept at a preset gap distance, namely a gap is arranged between the two electrodes; the cavity is arranged at the periphery of the gap, and the cavity is respectively propped against the pair of electrodes; and the thermal tripping device comprises a high-power resistor and an MCH heating body, and the high-power resistor and the MCH heating body are connected in series and then connected outside the discharge gap in parallel. When the high-power resistor is applied and pulse current exists, the gap is broken down due to the fact that voltage drop generated when part of current flows through the high-power resistor is higher than breakdown voltage in the gap, and most of the current flows through the gap instead of a thermal tripping device. When the surge protection device is influenced by power frequency overvoltage exceeding the voltage-sensitive voltage, current flows through the discharge gap thermal tripping device, and the current can be heated to the temperature for fusing a tin soldering point in a short time only by low current, so that the aim of separating the surge protection device from a power circuit is fulfilled.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of surge protection device, especially to a discharge gap external thermal trip device. BACKGROUND

[0002] The conventional surge protection device has two ways to disconnect from the power line when it fails: 1. The MOV generates a leakage current under the AC overvoltage of the line, and the zinc oxide semiconductor material will heat up under this current. As the current increases, the heat generated by the MOV further rises, and is conducted to the low-temperature soldering point through its metal pin. When the low-temperature soldering point is reached, the connection under the action of the spring pulls the pin and the power connection line apart, achieving the purpose of disconnecting the surge protection device from the power line; 2. The MOV and the temperature fuse are compounded together. When the power line has long-term overvoltage, the heat generated by the MOV is conducted to the temperature fuse, which melts internally, achieving the purpose of disconnecting from the power line.

[0003] The above two methods are based on the premise that the MOV can generate heat normally, but the MOV also has a failure mode of "thermal breakdown". Under a large instantaneous current, the MOV is thermally broken down, forming a low-resistance channel. At this time, the power frequency current flowing through the MOV will not heat up or the heat generated will be insufficient, and the surge protection device cannot be disconnected from the power line.

[0004] Therefore, the defects of the prior art are as follows,

[0005] The existing method for disconnecting the surge protection device from the power line when it fails is to use the leakage current flowing through the MOV. When the leakage current reaches a certain value, the MOV heats up enough to melt the low-temperature soldering point connected to the power line or make the temperature fuse connected in series with the MOV melt, thereby achieving the purpose of disconnecting the surge protection device from the power line.

[0006] However, when the MOV is thermally broken down, a low-resistance current channel is formed at the breakdown point, and the MOV will not continue to heat up or the heat generated will be insufficient, so the soldering point or the temperature fuse will not melt, and the surge protection device cannot be disconnected from the power line. SUMMARY

[0007] The utility model discloses a discharge gap external thermal trip device to at least solve one of the deficiencies of the prior art.

[0008] To achieve the above purpose, the utility model adopts the following technical scheme:

[0009] Specifically, a discharge gap external thermal trip device is proposed, comprising:

[0010] A pair of electrodes, a gap distance is maintained between the two electrodes, i.e. a gap is provided;

[0011] A cavity is arranged at the periphery of the gap, and the cavity is in abutment with a pair of the electrodes respectively.

[0012] The thermal trip device comprises a high-power resistor and an MCH heating body, the high-power resistor and the MCH heating body are connected in series, and then are connected in parallel outside the discharge gap.

[0013] Further, specifically,

[0014] The distance of the gap meets a preset range.

[0015] Further, specifically,

[0016] The cavity is a ceramic material member.

[0017] The utility model discloses a discharge gap external thermal trip device, and the high-power resistor and MCH heating piece are connected in series and then are connected in parallel outside the discharge gap, are combined and form a discharge gap external thermal trip device, and then the device and MOV are connected in series, when there is pulse current, because the high-power resistor has partial current to flow and generates voltage drop higher than the breakdown voltage inside the gap, so the gap is broken down, and the internal resistance value of the broken-down gap can be reduced to nearly zero, at this time, most of the current will flow through the gap instead of the thermal trip device. When the surge protector is affected by the power frequency overvoltage exceeding the voltage of the voltage-dependent resistor, no matter whether the voltage can cause the MOV thermal breakdown, the current will flow through the discharge gap thermal trip device, and the thermal trip device only needs small current to heat to the temperature of the melting tin soldering point in a short time, so as to achieve the purpose of separating the surge protector from the power line. BRIEF DESCRIPTION OF DRAWINGS

[0018] The above and other features of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which like reference numerals denote like elements or components, and in which:

[0019] Figure 1 The structure principle diagram of one embodiment of the discharge gap external thermal trip device is shown. DETAILED DESCRIPTION

[0020] The concept, specific structure and technical effects of the utility model will be described clearly and completely in combination with the embodiments and the drawings, so as to fully understand the purpose, scheme and effect of the utility model. It should be noted that the embodiments and the features in the embodiments in the present application can be combined with each other without conflict. The same reference numerals in the drawings indicate the same or similar parts.

[0021] Embodiment 1, refer to Figure 1 The utility model provides a discharge gap external thermal trip device, include:

[0022] A pair of electrodes 100, keep the gap distance of two electrode 100 is provided with gap 110 for the preset interval;

[0023] A cavity 200 is arranged at the periphery of the gap 110, and the cavity 200 is in abutment with a pair of the electrodes 100 respectively.

[0024] Thermal trip device, including high -power resistance 310 and MCH heating body 320, high -power resistance 310 with MCH heating body 320 series connection, then parallel in discharge gap 110 outside, wherein the electrode 100 of upper side is connected with MCH heating body through electrode extension foot 330.

[0025] In this embodiment 1, by high -power resistance 310 and MCH heating piece series connection parallel in discharge gap 110 outside, combination and form a kind of discharge gap external thermal trip device, again, the device is connected with MOV together, when there is pulse current, since high -power resistance 310 has partial current flow when generating voltage drop higher than the breakdown voltage inside gap 110, so gap 110 is broken down, the resistance value of gap 110 after breakdown will drop to nearly zero, at this time, most of the current will flow through gap 110 instead of thermal trip device. When the surge protection device is affected by the power frequency overvoltage exceeding the voltage of the voltage-dependent resistor, whether the voltage will cause the MOV thermal breakdown, the current will flow through the discharge gap 110 thermal trip device, and the thermal trip device only needs a small current to heat up to the temperature of the soldering point in a short time, so as to achieve the purpose of disconnecting the surge protection device from the power line.

[0026] As a preferred embodiment of the utility model, specifically,

[0027] The distance of the gap 110 meets the preset range.

[0028] In this preferred embodiment, the gap 110 is controlled within the industry standard range, which can meet the actual application scenarios of the utility model.

[0029] As a preferred embodiment of the utility model, specifically,

[0030] The cavity 200 is a ceramic material member.

[0031] In this preferred embodiment, the cavity is made of ceramic material, which can well adapt to the application scenarios of the utility model, and other insulating materials that can meet the actual application scenarios of the utility model are also possible.

[0032] Although the description of the present application has been quite detailed and particularly described with respect to several described embodiments, it is not intended to be limited to any of these details or embodiments or any particular embodiment, but rather it is to be considered to be broadly interpreted in view of the prior art by the appended claims providing a broad interpretation of the possibilities, thereby effectively encompassing the intended scope of the present application. Furthermore, the above description of the present application has been made with respect to embodiments as the inventors can foresee, the purpose of which is to provide a useful description, and those non-essential modifications to the present application that have not yet been foreseen can still represent equivalent modifications to the present application.

[0033] The above is only the preferred embodiment of the present application, and the present application is not limited to the above-described embodiments, as long as the same means achieve the technical effects of the present application, all should belong to the protection scope of the present application. The technical solutions and / or embodiments in the protection scope of the present application can have various modifications and changes.

Claims

1. An external trip device for a discharge gap, characterized in that The application relates to a high-voltage spark gap, which comprises: a pair of electrodes, a preset gap distance being kept between the two electrodes, i.e. a gap is arranged; a cavity made of insulating material, which is arranged at the periphery of the gap and abuts against the pair of electrodes respectively; a thermal tripping device, which comprises a high-power resistor and an MCH heating body, the high-power resistor and the MCH heating body are connected in series and then connected in parallel outside the discharge gap.

2. An external trip device for a discharge gap according to claim 1, characterized in that Specifically, the cavity is made of ceramic material.

Images