Comprehensive testing device for low-voltage current transformer

Abstract

The invention relates to the technical field of mutual inductor testing, in particular to a low-voltage current mutual inductor comprehensive testing device which comprises a conveying frame, the conveying frame is provided with a conveying belt used for conveying a plurality of sets of current mutual inductors, the upper end of the conveying belt is provided with separation blocks used for evenly separating the current mutual inductors, and the left portion of the upper end of the conveying frame is provided with a first installation frame. A guide plate is fixedly mounted in the first mounting frame, a detector is arranged at the upper end of the first mounting frame, the detector is electrically connected with a controller and a connector, two groups of symmetrical electrode plates are arranged at the bottom end of the connector, and the testing device comprises a dynamic connecting mechanism and a dynamic cleaning mechanism. The current transformer is provided with the separation block to control the contact between the electrode plate and the access end of the current transformer, so that the detector can rapidly detect the current transformer, batch detection is facilitated, and the detection efficiency of the current transformer is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of transformer testing, and in particular to a low-voltage current transformer comprehensive testing device. Background Art

[0002] The working principle of the current transformer is based on the law of electromagnetic induction. When an alternating current flows through the primary winding, an alternating magnetic flux will be generated in the iron core. This magnetic flux will induce an electromotive force in the secondary winding, thereby realizing the function of converting the large current on the primary side into a small current on the secondary side. Its main function is to measure and protect the current in the power system. By changing the size of the current, the current measurement and protection equipment can work within a safe and accurate range. At the same time, the current transformer can also isolate the electrical equipment of the high voltage system from the low voltage system to ensure the safety of the staff.

[0003] When testing existing current transformers, the wiring work of the primary and secondary ends of the transformer is mostly done manually, especially the secondary wiring of the through-type transformer. The high-intensity operation of the staff is not only prone to mistakes, but also increases the risk of electric shock to the staff. The test efficiency is low, and the current transformer is easily generated with debris and dust on the upper end after placement and stacking in various production processes. If it is not handled in time before detection, it will affect the stability of the current transformer detection connection.

[0004] Therefore, a comprehensive testing device for low voltage current transformer is proposed. Summary of the invention

[0005] The object of the present invention is to provide a low voltage current transformer comprehensive test device to solve the problems mentioned in the above background technology that current transformers are inconvenient for mass connection detection and debris and dust affect the connection stability.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a low-voltage current transformer comprehensive testing device, including a conveying frame, the conveying frame is provided with a conveyor belt for conveying several groups of current transformers, the upper end of the conveying belt is provided with a partition block that evenly separates the current transformers, a first mounting frame is provided on the left upper end of the conveying frame, a guide plate is fixedly installed inside the first mounting frame, a detector is provided on the upper end of the first mounting frame, the detector is electrically connected to the controller and the connector, and two symmetrical groups of electrode plates are provided at the bottom end of the connector. The testing device includes a dynamic connection mechanism and a dynamic cleaning mechanism. The automatic connection mechanism can use the structure of the partition block to drive the connector to rise and fall, so that the electrode plate at the bottom end of the connector can be connected and disconnected with the transformer access end on the current transformer, so that the guide plate can test multiple groups of current transformers, and the automatic cleaning mechanism uses the structure of the partition block to drive the second guide block to rise and fall, so that the inflation cylinder intermittently conveys gas into the air distribution pipe, so that the nozzle at the bottom end of the air distribution pipe cleans the transformer access end at the upper end of the current transformer.

[0007] Preferably, the dynamic connection mechanism includes a first guide block arranged inside the first mounting frame, the upper end of the first guide block is fixedly connected to one end of the first guide rod, and the other end of the first guide rod is also fixedly connected to the first limit plate, the upper end of the first limit plate is fixedly connected to one end of the steel wire rope, and the other end of the steel wire rope is fixedly connected to the second limit plate, the bottom end of the second limit plate is fixedly connected to one end of the second guide rod, and the other end of the second guide rod is also fixedly connected to the mounting plate, and the bottom end of the mounting plate is fixedly installed with a connecting head.

[0008] Preferably, an inclined guide surface is provided on one side of the separation block, and a first inclined surface is provided on one side of the first guide block, and the separation block is matched with the first guide block.

[0009] Preferably, a first return spring is arranged between the guide plate and the first guide block, and the first return spring is sleeved on the first guide rod. A second return spring is arranged between the guide plate and the mounting plate, and the second return spring is sleeved on the second guide rod. The restoring force of the first return spring is greater than the restoring force of the second return spring, and the restoring force of the first return spring can overcome the restoring force of the second return spring for reset.

[0010] Preferably, a slot is provided at the upper end of the separation block, and the slot is used for the connection head and the electrode plate to pass through.

[0011] Preferably, the outer side of the steel wire rope passes through a pulley, and the pulley is fixedly mounted on the top end of the first mounting frame.

[0012] Preferably, the dynamic cleaning mechanism includes a second mounting frame arranged on the right upper end of the conveying frame, the bottom end of the second mounting frame is fixedly connected to an air cylinder, the inside of the air cylinder is movably connected to a piston, the bottom end of the piston is fixedly connected to one end of a connecting rod, the other end of the connecting rod is fixedly connected to a second guide block, an air inlet pipe is arranged on the upper left side of the air cylinder, the top end of the air cylinder is fixedly connected to one end of an air supply pipe, the other end of the air supply pipe is fixedly connected to an air distribution pipe, and a nozzle is arranged at the bottom end of the air distribution pipe.

[0013] Preferably, a second inclined surface is provided on one side of the second guide block, and the second guide block is matched with the partition block.

[0014] Preferably, a third return spring is provided at the upper end of the piston, and the third return spring is arranged inside the inflation cylinder.

[0015] Preferably, one-way valves are provided on the outsides of the air inlet pipe and the air delivery pipe, and a plurality of groups of nozzles are evenly provided on the bottom end of the air distribution pipe, and the plurality of groups of nozzles can cover the surroundings of the access end of the transformer below.

[0016] Beneficial effects of the present invention:

[0017] 1. The present invention, by designing a dynamic connection mechanism, is conducive to setting a separator block on the current transformer to control the contact between the electrode plate and the transformer access end, so that the detector can quickly detect the current transformer, which is convenient for batch detection and greatly improves the detection efficiency of the current transformer. In addition, by setting a groove on the separator block, the descending distance of the electrode plate can be smaller than the rising distance of the first guide block, which will not interfere with the movement of the separator block and can also improve the stability of the contact between the electrode plate and the transformer access end.

[0018] 2. The present invention designs a dynamic cleaning mechanism, which is beneficial to utilizing the structure of the partition block to control the lifting and lowering of the second guide block, so that the inflation cylinder is continuously inflated and exhausted, which is convenient for the nozzle to accurately clean each current transformer and effectively prevent dust and debris from affecting the stable contact between the transformer access end and the electrode plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is an overall three-dimensional schematic diagram of a low-voltage current transformer comprehensive test device according to an embodiment of the present invention;

[0021] Figure 2A low voltage current transformer comprehensive test device according to an embodiment of the present invention Figure 1 Schematic diagram of the cross-section at AA in the middle;

[0022] Figure 3 A low voltage current transformer comprehensive test device according to an embodiment of the present invention Figure 2 The enlarged schematic diagram of point B in the middle;

[0023] Figure 4 A low voltage current transformer comprehensive test device according to an embodiment of the present invention Figure 2 The enlarged schematic diagram at C in the middle;

[0024] Figure 5 This is a three-dimensional schematic diagram of a current transformer and a separator block of a low-voltage current transformer comprehensive test device according to an embodiment of the present invention;

[0025] Figure 6 This is a three-dimensional schematic diagram of a detector and a connector of a low-voltage current transformer comprehensive test device according to an embodiment of the present invention;

[0026] Figure 7 This is an exploded schematic diagram of a dynamic connection mechanism of a low-voltage current transformer comprehensive test device according to an embodiment of the present invention;

[0027] Figure 8 It is a three-dimensional schematic diagram of a dynamic cleaning mechanism of a low-voltage current transformer comprehensive test device according to an embodiment of the present invention;

[0028] Fig. 9 This is an explosion schematic diagram of a dynamic cleaning mechanism of a low-voltage current transformer comprehensive testing device according to an embodiment of the present invention.

[0029] The markings in the figure are: 1. conveyor frame; 2. conveyor belt; 3. current transformer; 4. transformer access end; 5. separator block; 6. slot; 7. inclined guide surface; 8. first mounting frame; 9. guide plate; 10. detector; 11. controller; 12. connector; 13. electrode plate; 14. first guide block; 15. first inclined surface; 16. first guide rod; 17. first limit plate; 18. wire rope; 19. pulley; 20. second limit plate; 21. second guide rod; 22. mounting plate; 23. first return spring; 24. second return spring; 25. second mounting frame; 26. inflator; 27. piston; 28. connecting rod; 29. ​​second guide block; 30. second inclined surface; 31. third return spring; 32. air inlet pipe; 33. air supply pipe; 34. one-way valve; 35. air distribution pipe; 36. nozzle. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0031] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0032] See also Figures 1 to 9 The present invention provides a technical solution: a low-voltage current transformer comprehensive test device, including a conveyor frame 1, the conveyor frame 1 is provided with a conveyor belt 2 for conveying a plurality of groups of current transformers 3, the upper end of the conveyor belt 2 is provided with a partition block 5 for evenly separating the current transformers 3, a first mounting frame 8 is provided at the left upper end of the conveyor frame 1, a guide plate 9 is fixedly installed inside the first mounting frame 8, a detector 10 is provided at the upper end of the first mounting frame 8, the detector 10 is electrically connected to a controller 11 and a connector 12, and two symmetrical groups of electrode plates 13 are provided at the bottom end of the connector 12, and the test device includes Dynamic connection mechanism and dynamic cleaning mechanism, the automatic connection mechanism can use the structure of the partition block 5 to drive the connecting head 12 to rise and fall, so that the electrode plate 13 at the bottom end of the connecting head 12 can be connected and disconnected with the transformer access terminal 4 on the current transformer 3, so that the guide plate 9 can quickly test multiple groups of current transformers 3, and the automatic cleaning mechanism uses the structure of the partition block 5 to drive the second guide block 29 to rise and fall, so that the inflation cylinder 26 intermittently delivers gas to the air distribution pipe 35, so that the nozzle 36 at the bottom end of the air distribution pipe 35 cleans the transformer access terminal 4 at the upper end of the current transformer 3.

[0033] As an embodiment of the present invention, Figure 3 , Figure 5 , Figure 6 and Figure 7As shown, the dynamic connection mechanism includes a first guide block 14 arranged inside the first mounting frame 8, the upper end of the first guide block 14 is fixedly connected to one end of a first guide rod 16, the other end of the first guide rod 16 passes through the guide plate 9, and this end of the first guide rod 16 is fixedly connected to a first limiting plate 17, the upper end of the first limiting plate 17 is fixedly connected to one end of a steel wire rope 18, the other end of the steel wire rope 18 is fixedly connected to a second limiting plate 20, the bottom end of the second limiting plate 20 is fixedly connected to one end of a second guide rod 21, the other end of the second guide rod 21 passes through the guide plate 9, and this end of the second guide rod 21 is fixedly connected to a mounting plate 22, the bottom end of the mounting plate 22 is fixedly installed with a connector 12, an inclined guide surface 7 is provided on one side of the partition block 5, and the first guide block A first inclined surface 15 is provided on one side of 14, the separator block 5 is adapted to the first guide block 14, a first return spring 23 is provided between the guide plate 9 and the first guide block 14, the first return spring 23 is sleeved on the first guide rod 16, a second return spring 24 is provided between the guide plate 9 and the mounting plate 22, the second return spring 24 is sleeved on the second guide rod 21, the restoring force of the first return spring 23 is greater than the restoring force of the second return spring 24, the restoring force of the first return spring 23 can overcome the restoring force of the second return spring 24 for reset, that is, the restoring force of the first return spring 23 drives the first guide block 14 to descend, and a slot 6 is provided on the upper end of the separator block 5, the slot 6 is used for the passage of the connector 12 and the electrode plate 13, and prevents the separator block 5 from contacting the electrode plate 13 causes interference, the outer side of the wire rope 18 passes through the pulley 19, and the pulley 19 is fixedly installed on the top of the first mounting frame 8. When in use, the current transformer 3 is placed on the conveyor belt 2 separated by the partition block 5, and then the current transformer 3 drives the partition block 5 to move, so that the inclined guide surface 7 on the partition block 5 contacts the first inclined surface 15 on the first guide block 14, and then the partition block 5 drives the first guide block 14 to rise through the inclined guide surface 7 and the first inclined surface 15. Because the first guide block 14 and the connector 12 change the direction of force for traction through the wire rope 18 and the pulley 19, the rise of the first guide block 14 will reduce the overcoming force of the first return spring 23 on the second return spring 24, so that the restoring force of the second return spring 24 passes through the mounting plate 22 The electrode plate 13 at the bottom of the connector 12 is driven to stably contact the transformer access terminal 4 on the current transformer 3, so that the detector 10 can quickly detect the current transformer 3. Finally, when the partition block 5 is separated from the first guide block 14, the restoring force of the first reset spring 23 drives the first guide block 14 to descend again, and the first guide block 14 drives the electrode plate 13 at the bottom of the connector 12 to separate from the transformer access terminal 4 through the wire rope 18, thereby releasing the connection, which is conducive to setting the partition block 5 on the current transformer 3 to pull the control electrode plate 13 and the transformer access terminal 4. The contact, so that the detector 10 can quickly detect the current transformer 3, is convenient for batch detection, and greatly improves the detection efficiency of the current transformer 3. In addition, by setting the slot 6 on the partition block 5,The descending distance of the electrode plate 13 can be smaller than the ascending distance of the first guide block 14, which will not interfere with the movement of the partition block 5 and can also improve the contact stability between the electrode plate 13 and the transformer access terminal 4.

[0034] As an embodiment of the present invention, Figure 4 , Figure 8 and Fig. 9 As shown, the dynamic cleaning mechanism includes a second mounting frame 25 arranged at the right part of the upper end of the conveying frame 1, the bottom end of the second mounting frame 25 is fixedly connected to an air cylinder 26, the interior of the air cylinder 26 is movably connected to a piston 27, the bottom end of the piston 27 is fixedly connected to one end of a connecting rod 28, the other end of the connecting rod 28 is fixedly connected to a second guide block 29, an air inlet pipe 32 is arranged at the upper left part of the air cylinder 26, the top end of the air cylinder 26 is fixedly connected to one end of an air delivery pipe 33, the other end of the air delivery pipe 33 is fixedly connected to an air distribution pipe 35, and the bottom end of the air distribution pipe 35 is provided with The nozzle 36, a second inclined surface 30 is provided on one side of the second guide block 29, the second guide block 29 is adapted to the partition block 5, the upper end of the piston 27 is provided with a third return spring 31, the third return spring 31 is arranged inside the inflator 26, the outer sides of the air inlet pipe 32 and the air delivery pipe 33 are provided with a one-way valve 34, and the bottom end of the air distribution pipe 35 is evenly provided with a plurality of groups of nozzles 36, and the plurality of groups of nozzles 36 can cover the surrounding of the transformer access end 4 below. First, the current transformer 3 drives the partition block 5 to move, so that the inclined guide surface 7 on the partition block 5 and the first on the second guide block 29 are aligned. When the two inclined surfaces 30 come into contact, the partition block 5 drives the second guide block 29 to rise through the inclined guide surface 7 and the second inclined surface 30, and then the second guide block 29 drives the piston 27 in the inflatable cylinder 26 to rise through the connecting rod 28, and the piston 27 delivers the gas in the inflatable cylinder 26 to the air distribution pipe 35 through the air delivery pipe 33, so that the nozzle 36 at the bottom end of the air distribution pipe 35 blows and cleans the transformer access end 4 on the current transformer 3, and finally when the partition block 5 is separated from the second guide block 29, the restoring force of the third reset spring 31 drives the piston 27 to descend, so that the inflatable cylinder 26 passes through the inlet pipe 33, and the inflatable cylinder 26 passes through the inlet pipe 33. The air pipe 32 inhales gas for replenishment, so that the piston 27 drives the second guide block 29 to return to its original position through the connecting rod 28, which is convenient for next use. A one-way valve 34 is set on the air inlet pipe 32 and the air supply pipe 33 to avoid gas backflow and ensure the stability of gas flow. It is beneficial to use the structure of the partition block 5 to control the lifting and lowering of the second guide block 29, so that the inflation cylinder 26 can continuously inflate and exhaust, which is convenient for the nozzle 36 to accurately clean each current transformer 3, and effectively prevent dust and debris from affecting the stable contact between the transformer access end 4 and the electrode plate 13.

[0035] Working principle: First, the current transformer 3 drives the partition block 5 to move, so that the inclined guide surface 7 on the partition block 5 contacts the second inclined surface 30 on the second guide block 29, and then the partition block 5 drives the second guide block 29 to rise through the inclined guide surface 7 and the second inclined surface 30, and then the second guide block 29 drives the piston 27 in the inflation cylinder 26 to rise through the connecting rod 28, and the piston 27 transports the gas in the inflation cylinder 26 to the air distribution pipe 35 through the air supply pipe 33, so that the nozzle 36 at the bottom end of the air distribution pipe 35 blows and cleans the transformer access end 4 on the current transformer 3, and finally when the partition block 5 is separated from the second guide block 29, the restoring force of the third reset spring 31 drives the piston 27 to descend, so that the inflation cylinder 26 inhales gas through the intake pipe 32 for replenishment, so that the piston 27 drives the second guide block 29 to return to its original position through the connecting rod 28, which is convenient for next use, and by arranging a one-way valve 34 on the intake pipe 32 and the air supply pipe 33, gas backflow is avoided to ensure the stability of gas flow;

[0036] The current transformer 3 is placed on the conveyor belt 2 separated by the separator 5, and then the current transformer 3 drives the separator 5 to move, so that the inclined guide surface 7 on the separator 5 contacts the first inclined surface 15 on the first guide block 14, and then the separator 5 drives the first guide block 14 to rise through the inclined guide surface 7 and the first inclined surface 15. Because the first guide block 14 and the connector 12 change the direction of force for traction through the wire rope 18 and the pulley 19, the rise of the first guide block 14 causes the first return spring 23 to resist the second return spring 24. The service force decreases, so that the restoring force of the second return spring 24 drives the electrode plate 13 at the bottom of the connector 12 to stably contact the transformer access terminal 4 on the current transformer 3 through the mounting plate 22, so that the detector 10 can quickly detect the current transformer 3. Finally, when the partition block 5 is separated from the first guide block 14, the restoring force of the first return spring 23 drives the first guide block 14 to descend again, and the first guide block 14 drives the electrode plate 13 at the bottom of the connector 12 to separate from the transformer access terminal 4 through the wire rope 18, thereby releasing the connection.

[0037] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0038] The present invention is intended to cover all such substitutions, modifications and changes that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A low-voltage current transformer comprehensive test device, comprising a conveyor frame (1), the conveyor frame (1) is provided with a conveyor belt (2) for conveying a plurality of groups of current transformers (3), the upper end of the conveyor belt (2) is provided with a partition block (5) for evenly separating the current transformers (3), a first mounting frame (8) is provided at the left upper end of the conveyor frame (1), a guide plate (9) is fixedly installed inside the first mounting frame (8), a detector (10) is provided at the upper end of the first mounting frame (8), the detector (10) is electrically connected to a controller (11) and a connector (12), and the bottom end of the connector (12) is provided with two symmetrical groups of electrode plates (13), characterized in that: The test device comprises a dynamic connection mechanism and a dynamic cleaning mechanism. The automatic connection mechanism can use the structure of the partition block (5) to drive the connection head (12) to rise and fall, so that the electrode plate (13) at the bottom end of the connection head (12) can be connected to and disconnected from the transformer access end (4), so that the guide plate (9) can test multiple groups of current transformers (3). The automatic cleaning mechanism uses the structure of the partition block (5) to drive the second guide block (29) to rise and fall, so that the inflation cylinder (26) intermittently delivers gas to the air distribution pipe (35), so that the nozzle (36) at the bottom end of the air distribution pipe (35) cleans the transformer access end (4).

2. A low voltage current transformer comprehensive test device according to claim 1, characterized in that: The dynamic connection mechanism comprises a first guide block (14) arranged inside the first mounting frame (8); the upper end of the first guide block (14) is fixedly connected to one end of a first guide rod (16); the other end of the first guide rod (16) is fixedly connected to a first limit plate (17); the upper end of the first limit plate (17) is fixedly connected to one end of a steel wire rope (18); the other end of the steel wire rope (18) is fixedly connected to a second limit plate (20); the bottom end of the second limit plate (20) is fixedly connected to one end of a second guide rod (21); the other end of the second guide rod (21) is fixedly connected to a mounting plate (22); the bottom end of the mounting plate (22) is fixedly mounted with a connector (12).

3. A low voltage current transformer comprehensive test device according to claim 2, characterized in that: An inclined guide surface (7) is provided on one side of the separation block (5), and a first inclined surface (15) is provided on one side of the first guide block (14), and the separation block (5) is adapted to the first guide block (14).

4. A low voltage current transformer comprehensive test device according to claim 2, characterized in that: A first return spring (23) is arranged between the guide plate (9) and the first guide block (14), and a second return spring (24) is arranged between the guide plate (9) and the mounting plate (22); the restoring force of the first return spring (23) is greater than the restoring force of the second return spring (24); and the restoring force of the first return spring (23) can overcome the restoring force of the second return spring (24) for reset.

5. A low voltage current transformer comprehensive test device according to claim 2, characterized in that: The upper end of the separation block (5) is provided with a slot (6), and the slot (6) is used for the connection head (12) and the electrode plate (13) to pass through.

6. A low voltage current transformer comprehensive test device according to claim 2, characterized in that: The outer side of the steel wire rope (18) passes through a pulley (19), and the pulley (19) is fixedly mounted on the top end of the first mounting frame (8).

7. A low voltage current transformer comprehensive test device according to claim 1, characterized in that: The dynamic cleaning mechanism comprises a second mounting frame (25) arranged at the right upper end of the conveying frame (1); the bottom end of the second mounting frame (25) is fixedly connected to an air cylinder (26); the interior of the air cylinder (26) is movably connected to a piston (27); the bottom end of the piston (27) is fixedly connected to one end of a connecting rod (28); the other end of the connecting rod (28) is fixedly connected to a second guide block (29); an air inlet pipe (32) is arranged at the upper left side of the air cylinder (26); the top end of the air cylinder (26) is fixedly connected to one end of an air supply pipe (33); the other end of the air supply pipe (33) is fixedly connected to an air distribution pipe (35); and a nozzle (36) is arranged at the bottom end of the air distribution pipe (35).

8. A low voltage current transformer comprehensive test device according to claim 7, characterized in that: A second inclined surface (30) is provided on one side of the second guide block (29), and the second guide block (29) is adapted to the partition block (5).

9. A low voltage current transformer comprehensive test device according to claim 7, characterized in that: A third return spring (31) is arranged at the upper end of the piston (27), and the third return spring (31) is arranged inside the inflation cylinder (26).

10. A low voltage current transformer comprehensive test device according to claim 7, characterized in that: The outsides of the air inlet pipe (32) and the air delivery pipe (33) are both provided with a one-way valve (34), and the bottom end of the air distribution pipe (35) is evenly provided with a plurality of groups of nozzles (36), and the plurality of groups of nozzles (36) can cover the surroundings of the lower transformer access end (4).

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