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EP-4322183-B1 - THERMALLY PROTECTED VARISTOR

EP4322183B1EP 4322183 B1EP4322183 B1EP 4322183B1EP-4322183-B1

Inventors

  • TANG, Yuecong
  • ZHANG, Xianggui
  • YUAN, YUXIANG
  • JIANG, JIANGUO
  • WANG, Xiaolou

Dates

Publication Date
20260506
Application Date
20230414

Claims (7)

  1. A thermally protected varistor, comprising a frame (1), a varistor (2), a slider (3), an elastic member (4), and an electrode (5), wherein the slider (3) is provided between the electrode (5) and the varistor (2); the electrode (5) is welded to an electrode of the varistor (2) through a low-melting-point alloy (51); the elastic member (4) is connected to the slider (3) to drive the slider (3) to abut against a welded position comprising the low-melting-point alloy between the electrode (5) and the varistor (2); and a wrapper (6) made of a heat-resisting material is provided outside the slider (3), and a melting point of the heat-resisting material is greater than 350°C; the frame (1) is provided with a first remote signaling electrode (81) and a second remote signaling electrode (82); and when the electrode (5) is disconnected from the varistor (2), a connection state between the first remote signaling electrode (81) and the second remote signaling electrode (82) changes accordingly; the slider (3) is provided with a compression part (31) and a limit part (32); and the frame (1) is provided with an insertion slot (15); and when the electrode (5) is connected to the varistor (2), the limit part (32) is inserted into the insertion slot (15), and the compression part (31) compresses the first remote signaling electrode (81) and the second remote signaling electrode (82), such that the first remote signaling electrode (81) and the second remote signaling electrode (82) are connected to form a normally closed remote signaling alarm; and when the electrode (5) is disconnected from the varistor (2), the limit part (32) is pulled out of the insertion slot (15), and the first remote signaling electrode (81) and the second remote signaling electrode (82) are rebounded and disconnected; or the slider (3) is provided with a compression part (31) and a hook groove (33); and when the electrode (5) is connected to the varistor (2), the compression part (31) compresses the first remote signaling electrode (81), and the second remote signaling electrode (82) extends into the hook groove (33), such that the first remote signaling electrode (81) and the second remote signaling electrode (82) are disconnected to form a normally opened remote signaling alarm; and when the electrode (5) is disconnected from the varistor (2), the compression part (31) is disconnected from the first remote signaling electrode (81), and an inner wall of the hook groove (33) moves the second remote signaling electrode (82) to rebound, such that the first remote signaling electrode (81) and the second remote signaling electrode (82) are connected.
  2. The thermally protected varistor according to claim 1, wherein a back side of the frame (1) is provided with a mounting slot (11) for accommodating the varistor (2), and a front side of the frame (1) is provided with a storage slot (12) for accommodating the electrode (5); the frame (1) is provided with a through hole communicated with the storage slot (12) through the mounting slot (11); the electrode of the varistor (2) is welded to the electrode (5) through the through hole; and the slider (3) is slidably provided in the storage slot (12).
  3. The thermally protected varistor according to claim 1, wherein the wrapper (6) is a U-shaped shell sleeved on the slider (3).
  4. The thermally protected varistor according to claim 1, wherein the wrapper (6) is a ceramic layer.
  5. The thermally protected varistor according to claim 1, wherein the first remote signaling electrode (81) and the second remote signaling electrode (82) are abutted against a limit slot of the frame (1); and each of a side of the first remote signaling electrode (81) abutted against the frame (1) and a side of the second remote signaling electrode (82) abutted against the frame (1) is provided with a ventilation gap (83).
  6. The thermally protected varistor according to claim 1 or 2, wherein the varistor (2) is connected in series with a discharge tube (7).
  7. The thermally protected varistor according to claim 6, wherein the back side of the frame (1) is provided with a mounting slot (11) for accommodating the varistor (2), an accommodation slot (13) for accommodating the discharge tube (7), and a connection slot (14); and the electrode of the varistor (2) and an electrode of the discharge tube (7) extend into the connection slot (14) and are connected to each other.

Description

CROSS REFERENCE TO THE RELATED APPLICATIONS The present disclosure claims priority to Chinese Patent Application 202220910687.2, filed with the China National Intellectual Property Administration (CNIPA) on April 20, 2022, and titled "THERMALLY PROTECTED VARISTOR'. TECHNICAL FIELD The present disclosure relates to the technical field of surge protection circuits, and in particular to a thermally protected varistor. BACKGROUND A thermally protected varistor is an overvoltage protection device used for electrical equipment. When the varistor encounters overvoltage, the low-melting-point alloy between the electrode of the varistor and the electrode melts due to being heated, such that the varistor is disconnected from the electrode to protect the electrical equipment. However, there is a problem with the existing thermally protected varistor on the market. When a lightning current of 50 A or above passes through the thermally protected varistor, the disconnecting device made of a material with a melting point of 100-350°C usually cannot effectively break the arc. As a result, the material of the disconnecting device will melt and even catch fire to damage the electrical equipment, thereby threatening the safety of equipment and personnel. CN 208 570 238 U discloses a thermally protected varistor including shell, chip assembly, moving electrode, low-melting alloy layer, sliding block, spring, etc. CN 211 908 358 U discloses a thermally protected varistor including a frame, a thermal tripping device, a piezoresistor component, etc. CN 214 958 700 U discloses a blocking type surge protector tripping device. None of these references discloses a thermally protected varistor having the claimed structural configuration and interaction. SUMMARY To solve the problem occurring when the existing varistor is disconnected, wherein the material of the disconnecting device is prone to melt and even catch fire to damage the electrical equipment, the present disclosure provides a thermally protected varistor as defined in claim 1. The above description is merely a summary of the technical solutions of the present disclosure. In order to make the technical means of the present disclosure understood more clearly and implemented in accordance with the content of the specification, and in order to make the above and other objectives, features and advantages of the present disclosure more obvious and comprehensible, specific implementations of the present disclosure are described below. BRIEF DESCRIPTION OF THE DRAWINGS To describe the technical solutions in the embodiments of the present disclosure or in the prior art more clearly, the following briefly describes the drawings required for describing the embodiments or the prior art. Apparently, the drawings in the following description merely show some embodiments of the present disclosure, and those of ordinary skill in the art may still derive other drawings from these drawings without creative efforts. FIG. 1 is an exploded view of a first thermally protected varistor according to an embodiment of the present disclosure;FIG. 2 is an internal structural diagram of the thermally protected varistor, shown in FIG. 1, in a disconnected state;FIG. 3 is a sectional view of the thermally protected varistor shown in FIG. 2;FIG. 4 is an internal structural diagram of the thermally protected varistor, shown in FIG. 1, in a connected state;FIG. 5 is a sectional view of the thermally protected varistor shown in FIG. 4;FIG. 6 is a schematic diagram of a slider and a wrapper of the thermally protected varistor shown in FIG. 1;FIG. 7 is a structural diagram of a first remote signaling electrode and a second remote signaling electrode of the thermally protected varistor shown in FIG. 1;FIG. 8 is an internal structural diagram of a second thermally protected varistor according to an embodiment of the present disclosure;FIG. 9 is an internal structural diagram of the thermally protected varistor, shown in FIG. 8, in a disconnected state;FIG. 10 is a circuit diagram of a third thermally protected varistor according to an embodiment of the present disclosure;FIG. 11 is a structural diagram of a back side of the third thermally protected varistor according to an embodiment of the present disclosure;FIG. 12 is a circuit diagram of a fourth thermally protected varistor according to an embodiment of the present disclosure; andFIG. 13 is a circuit diagram of a fifth thermally protected varistor according to an embodiment of the present disclosure. Reference Numerals: 1. frame; 11. mounting slot; 12. storage slot; 13. accommodation slot; 14. connection slot; 15. insertion slot; 2. varistor; 3. slider; 31. compression part; 32. limit part; 33. hook groove; 4. elastic member; 5. electrode; 51. low-melting-point alloy; 6. wrapper; 7. discharge tube; 81. first remote signaling electrode; 82. second remote signaling electrode; and 83. ventilation gap. DETAILED DESCRIPTION OF THE EMBODIMENTS To make the above