Voltage transformer with secondary short circuit and overload protection function

Abstract

The utility model discloses a voltage transformer with secondary short circuit and overload protection function, increase short circuit current -limiting function to mutual inductor body, realize the full protection in the range of terminal instrument line from secondary outgoing line terminal. The voltage transformer includes mutual inductor body, bottom plate, at least a pair of secondary outgoing line terminal, insert piece, secondary winding group, fuse device and apron, and the mutual inductor body is through casting molding and is installed on the bottom plate, and its side is provided with mounting groove, the secondary outgoing line terminal is embedded in the surface of mutual inductor body, a pair of insert pieces are embedded on the lateral wall of mounting groove, and the secondary winding group is located in the mutual inductor body, and one end is electrically connected with its secondary outgoing line terminal, and the other end is electrically connected with its insert piece, and the other insert piece is electrically connected with the other secondary outgoing line terminal, and the fuse device is temperature fuse or current -limiting fuse, and it is detachably connected between two insert pieces, and the apron is detachably installed at the opening of mounting groove.

Description

Technical Field

[0001] This utility model belongs to the technical field of voltage transformers, and specifically refers to a voltage transformer with secondary short-circuit and overload protection functions. Background Technology

[0002] When a voltage transformer is put into operation in a system, its secondary side is connected in parallel with some instruments and protection devices. During operation, these devices may experience overload or short circuit faults in the secondary circuit. In order to protect the parallel-connected secondary devices and the voltage transformer itself from damage, the existing technology uses a miniature air switch connected in series in the secondary circuit of the voltage transformer. When an excessive current is detected, the miniature air switch will cut off the circuit, thus providing good protection in application.

[0003] However, in practical applications, although an air switch is added to the secondary side of the voltage transformer, situations may still occur such as accidental connection of two grounding points at the secondary terminals or short circuit of the external insulation of the winding lead wire, which may lead to the burnout of the voltage transformer. Utility Model Content

[0004] The main purpose of this utility model is to provide a voltage transformer with secondary short-circuit and overload protection functions, solve the problems existing in the prior art, add short-circuit current limiting function to the transformer body, and realize full protection from the secondary output terminal to the terminal instrument line range.

[0005] To achieve the above objectives, the solution of this utility model is:

[0006] A voltage transformer with secondary short-circuit and overload protection functions includes a transformer body, a base plate, at least one pair of secondary output terminals, inserts, a secondary winding assembly, a fuse, and a cover plate. The transformer body is formed by casting and mounted on the base plate, with a mounting groove on its side. The secondary output terminals are embedded in the surface of the transformer body. A pair of inserts are embedded in the side wall of the mounting groove. The secondary winding assembly is located inside the transformer body, with one end electrically connected to one of its secondary output terminals and the other end electrically connected to one of its inserts. The other insert is electrically connected to another secondary output terminal. The fuse is a thermal fuse or a current-limiting fuse, which is detachably connected between the two inserts. The cover plate is detachably mounted at the opening of the mounting groove.

[0007] The mounting slot is located at the bottom side of the transformer body.

[0008] The transformer body has mounting slots on both sides, and two pairs of secondary output terminals are provided, with all secondary output terminals arranged side by side at the same end of the transformer body.

[0009] The cover plate is made of a transparent material.

[0010] The mounting groove has an installation step at its opening, and nuts are embedded at the four corners of the installation step. The cover plate is secured to the corresponding nuts at the four corners by a screw.

[0011] Preferably, after the cover plate is fitted onto the mounting step, the outer side of the cover plate is flush with the side of the transformer body.

[0012] Preferably, the nut is embedded in the corresponding position of the mounting step during the casting and molding of the transformer body.

[0013] The insert is made of a conductive material.

[0014] When the fuse is a thermal fuse, both ends of the thermal fuse are provided with ring terminals, and screws are passed through the ring terminals and locked into the corresponding inserts.

[0015] When the fuse is a current-limiting fuse, a pair of conductive clips are provided in the mounting groove, and the conductive clips are connected and fixed to the inserts at the corresponding positions; the end of the current-limiting fuse is embedded in the conductive clips.

[0016] After adopting the above technical solution, the present invention has the following technical effects:

[0017] (1) Integrating a temperature fuse or current-limiting fuse with short-circuit current-limiting function into the inside of the transformer body can achieve full protection from the secondary output terminal to the terminal instrument line.

[0018] (2) Based on the different limit outputs of the current transformer and the ambient temperature, the corresponding rated current and rated temperature can be matched to select different temperature fuses or current-limiting fuses, so that the protection effect is stronger.

[0019] (3) Thanks to the convenient replacement of the cover plate, the fuse device in the installation slot can be quickly replaced to ensure the long-term stable operation of the equipment. The cover plate can also play a role in preventing accidental contact and dust prevention.

[0020] (4) Use temperature fuses or current-limiting fuses as fuse devices. Their size is small, and opening the mounting groove on the side of the transformer body will not affect the coil structure inside the product and the creepage distance of the product. Attached Figure Description

[0021] Figure 1 This is a perspective view of the present invention.

[0022] Figure 2 This is a partial exploded view of the first embodiment of the present invention.

[0023] Figure 3 This is a partial three-dimensional view of the first embodiment of the present utility model.

[0024] Figure 4 This is a partial exploded view of the second embodiment of the present invention.

[0025] Figure 5 This is a partial three-dimensional view of the second embodiment of the present utility model.

[0026] Figure 6 This is a perspective view of the casting side plate of this utility model.

[0027] Figure 7 This is a schematic diagram of the casting side plate of this utility model.

[0028] Explanation of icon numbers:

[0029] 1-Inductor body; 11-Mounting slot; 12-Mounting step; 2-Base plate; 3, 3'-Secondary output terminals; 4, 4'-Insertions; 5-Secondary winding assembly; 6-Cover plate; 7-Temperature fuse; 71-Ring terminal; 8-Current limiting fuse; 9-Nut; 10, 20-Screws; 30-Conductive clamp; 40-Cast side plate; 401-Protrusion; 402-Boss; 403-Cavity; 404-First through hole; 405-Second through hole; 50-Locking fastener. Detailed Implementation

[0030] To further explain the technical solution of this utility model, the following detailed description is provided through specific embodiments.

[0031] refer to Figures 1 to 5 As shown, this utility model discloses a voltage transformer with secondary short-circuit and overload protection functions, including a transformer body 1, a base plate 2, at least one pair of secondary output terminals 3, an insert 4, a secondary winding group 5, a fuse device and a cover plate 6.

[0032] The transformer body 1 is formed by casting and installed on the base plate 2, and its side is provided with a mounting groove 11;

[0033] Secondary output terminals 3 are embedded on the surface of the transformer body 1 for connecting secondary equipment (such as some instruments and protection devices).

[0034] A pair of inserts 4 are embedded in the side wall of the mounting groove 11;

[0035] See Figure 3 , Figure 5The secondary winding assembly 5 is located inside the transformer body 1. One end of it is welded and fixed to its primary secondary output terminal 3 to achieve electrical connection, and the other end is welded and fixed to its insert 4 to achieve electrical connection; the other insert 4' is connected to the other secondary output terminal 3' through a flexible wire to achieve electrical connection.

[0036] The fuse is a thermal fuse 7 or a current-limiting fuse 8, which is detachably connected between the two inserts 4;

[0037] The cover plate 6 is detachably installed at the opening of the mounting groove 11.

[0038] Through the above solution, this utility model integrates a temperature fuse 7 or a current-limiting fuse 8 with short-circuit current-limiting function into the inside of the transformer body 1, which can realize full protection from the secondary output terminal 3 to the terminal instrument line range; this utility model can match the corresponding rated current and rated temperature according to the different extreme output of the transformer and the ambient temperature to select different temperature fuses 7 or current-limiting fuses 8, so as to achieve stronger protection effect; thanks to the convenient replacement of the cover plate 6, the fuse device in the mounting groove 11 can be quickly replaced to ensure the long-term stable operation of the equipment. The cover plate 6 can also play a role in preventing accidental contact and dust prevention; the temperature fuse 7 or current-limiting fuse 8 is selected as the fuse device, which is small in size. The mounting groove 11 opened on the side of the transformer body 1 will not affect the coil structure inside the product and the creepage distance of the product.

[0039] Specifically, the mounting groove 11 is located at the bottom side of the transformer body 1 after casting, thus avoiding the primary high-voltage coil and core of the transformer. In this embodiment, mounting grooves 11 are provided on both sides of the transformer body 1, and two pairs of secondary output terminals 3 are provided accordingly. All secondary output terminals 3 are arranged side by side at the same end of the transformer body 1 for easy connection of external equipment.

[0040] When using thermal fuse 7 as the fuse, different rated current thermal fuses 7 can be selected based on the product's maximum output load, resulting in stronger protection. Simultaneously, the rated temperature can be dynamically selected based on the ambient temperature of the installation environment; for example, a 70℃ rated temperature fuse can be selected for an ambient temperature of 10℃, and a 110℃ rated temperature fuse can be selected for an ambient temperature of 50℃. The protection effect of thermal fuse 7 is superior to that of current-limiting fuse 8 because: current-limiting fuse 8 has an ampere-second characteristic during fusing. When a small current occurs in the system, the fuse can withstand it for a period of time, but it cannot immediately cut off the circuit. However, continuous fault current will accumulate heat inside the product and burn out the transformer. Therefore, in the case of small current faults, the protection effect of thermal fuse 7 on the transformer is better than that of current-limiting fuse 8.

[0041] The cover plate 6 is made of transparent material, which allows for easy observation of the status of the fuse device in the mounting groove 11.

[0042] Furthermore, an installation step 12 is provided at the opening of the aforementioned mounting groove 11, and nuts 9 are embedded at the four corners of the installation step 12. The four corners of the cover plate 6 are respectively locked to the corresponding nuts 9 by a screw 10. Moreover, after the cover plate 6 is fitted with the installation step 12, the outer side of the cover plate 6 is flush with the side of the transformer body 1 to avoid protrusion, which can ensure a neat appearance and avoid bumps.

[0043] Secondly, the aforementioned nut 9 is embedded in the corresponding position of the mounting step 12 during the casting and molding of the transformer body 1.

[0044] The aforementioned insert 4 is made of conductive material to ensure that the secondary side of the current transformer can form a circuit when the fuse is working normally.

[0045] The aforementioned transformer body 1 has an insert at the bottom during casting. Therefore, during installation, the base plate 2 and the insert are locked together with screws to achieve the installation of the transformer body 1 on the base plate 2.

[0046] refer to Figure 2 , 3 The first embodiment of the present invention is shown in the figure.

[0047] In the first embodiment, the above-mentioned fuse device is a thermal fuse 7, with annular terminals 71 at both ends. A screw 20 is passed through the annular terminals 71 and locked into the corresponding insert 4 to achieve a detachable connection between the thermal fuse 7 and the insert 4.

[0048] refer to Figure 4 , 5 As shown, a second embodiment of the present invention is illustrated.

[0049] In the second embodiment, the aforementioned fuse is a current-limiting fuse 8; a pair of conductive clips 30 are provided in the mounting groove 11, and the conductive clips 30 and the corresponding inserts 4 are fixedly connected by screws; the end of the current-limiting fuse 8 is embedded in the conductive clips 30 to achieve a detachable connection between the current-limiting fuse 8 and the inserts 4.

[0050] The forming process of the above-mentioned mounting groove 11 can be achieved by means of... Figure 6 , 7The casting side plate 40 shown is used for auxiliary molding. Specifically, the casting side plate 40 is the side plate of the molding mold for the transformer body 1. Its inner surface has a protrusion 401 with the same size as the mounting groove 11. A boss 402 is provided between the protrusion 401 and the casting side plate 40, which corresponds to the mounting step 12 at the opening of the mounting groove 11. A cavity 403 is provided inside the protrusion 401, which connects to the outer surface of the casting side plate 40. A through hole 404 is provided between the cavity 403 and both ends of the protrusion 401. Thus, when casting the transformer body 1, two inserts 4 can be fixed to both ends of the protrusion 401 using fasteners 50 (such as screws) to ensure that the inserts 4 are located in the preset position of the mounting groove 11 after molding. When demolding, the fasteners 50 are removed from the cavity 403, and the casting side plate can be removed. Meanwhile, the four corners of the boss 402 are also provided with second through holes 405 for fixing nuts 9. The second through holes 405 penetrate the inner and outer sides of the casting side plate 40.

[0051] The above embodiments and figures are not intended to limit the product form and style of this utility model. Any appropriate changes or modifications made by those skilled in the art should be considered as not departing from the patent scope of this utility model.

Claims

1. A voltage transformer with secondary short-circuit and overload protection functions, characterized in that: It includes the transformer body, base plate, at least one pair of secondary output terminals, insert, secondary winding assembly, fuse device and cover plate; The transformer body is formed by casting and installed on the base plate, and a mounting groove is provided on its side. The secondary output terminal is embedded in the surface of the current transformer body; A pair of inserts are embedded in the side wall of the mounting groove; The secondary winding assembly is located within the transformer body, with one end electrically connected to one of its secondary output terminals and the other end electrically connected to one of its inserts; the other insert is electrically connected to another secondary output terminal. The fuse is a thermal fuse or a current-limiting fuse, which is detachably connected between the two inserts; The cover plate is detachably installed at the opening of the mounting slot.

2. The voltage transformer with secondary short-circuit and overload protection functions as described in claim 1, characterized in that: The mounting slot is located at the bottom side of the transformer body.

3. The voltage transformer with secondary short-circuit and overload protection functions as described in claim 1 or 2, characterized in that: The transformer body has mounting slots on both sides, and two pairs of secondary output terminals are provided, with all secondary output terminals arranged side by side at the same end of the transformer body.

4. The voltage transformer with secondary short-circuit and overload protection functions as described in claim 1, characterized in that: The cover plate is made of a transparent material.

5. The voltage transformer with secondary short-circuit and overload protection functions as described in claim 1 or 4, characterized in that: The mounting groove has an installation step at its opening, and nuts are embedded at the four corners of the installation step. The cover plate is secured to the corresponding nuts at the four corners by a screw.

6. The voltage transformer with secondary short-circuit and overload protection functions as described in claim 5, characterized in that: After the cover plate is fitted onto the mounting step, the outer side of the cover plate is flush with the side of the transformer body.

7. The voltage transformer with secondary short-circuit and overload protection functions as described in claim 5, characterized in that: The nut is embedded in the corresponding position of the mounting step during the casting and molding of the transformer body.

8. The voltage transformer with secondary short-circuit and overload protection functions as described in claim 1, characterized in that: The insert is made of a conductive material.

9. The voltage transformer with secondary short-circuit and overload protection functions as described in claim 1, characterized in that: When the fuse is a thermal fuse, both ends of the thermal fuse are provided with ring terminals, and screws are passed through the ring terminals and locked into the corresponding inserts.

10. The voltage transformer with secondary short-circuit and overload protection functions as described in claim 1, characterized in that: When the fuse is a current-limiting fuse, a pair of conductive clips are provided in the mounting groove, and the conductive clips are connected and fixed to the inserts at the corresponding positions; the end of the current-limiting fuse is embedded in the conductive clips.

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