Fault current triggering device and vacuum circuit breaker

Abstract

The present invention provides a fault current trigger device and a vacuum circuit breaker having the fault current trigger device. The fault current trigger device includes an electromagnetic trip trigger and a thermal trip trigger. The electromagnetic trip trigger includes: a yoke, an armature, a push rod and a damping member. The yoke is sleeved on the outer peripheral side of a wiring board and has an opening. The armature is directly opposite to the opening of the yoke and is parallel to the opening of the yoke with a certain gap. The damping member applies a resistance to the armature to prevent it from moving toward the yoke. The push rod is fixedly connected to the armature and corresponds to the traction rod of the trip device. The thermal trip trigger includes a magnetic induction heating component arranged on the wiring board and a bimetallic strip connected to the magnetic induction heating component, and the bimetallic strip corresponds to the traction rod of the trip device. It can be well suitable for use in large current (greater than 800A) circuit breakers.

Description

Technical Field

[0001] The invention relates to the field of circuit breakers, and in particular to a fault current triggering device and a vacuum circuit breaker having the fault current triggering device. Background Art

[0002] A circuit breaker is a device used to control a circuit. When a circuit fault occurs, the circuit breaker cuts off the line through the tripping device, thereby protecting the line and the load on the line. The tripping device is triggered by the fault current triggering device set on the terminal board.

[0003] like Figure 1 The structure shown is a typical fault current trigger device, which is often used in molded case circuit breakers, generally used for circuit breakers with currents of 800A and below. The conductive plate 1 and the thermal element 2 are connected in series, and the electromagnetic trip trigger part and the thermal trip trigger part are both arranged on the thermal element 2. The bimetallic strip 4 of the thermal trip trigger part is directly connected to the thermal element 2 for long-delay overload tripping; the electromagnetic trip trigger part adopts a snap-on structure, that is, the armature 3 is pivotally arranged, and the magnetic field generated when the current of the terminal block is too large attracts the armature 3, and the armature 3 swings to hit the traction plate of the trip device to trigger the trip device for short-circuit instantaneous tripping; in this structure, the thermal element 2 is equivalent to a resistor, which generates heat during the conduction process. In addition, the two ends of the conductive plate 1 and the thermal element 2 are generally connected by screw crimping or direct welding, resulting in large contact resistance between the parts, large heat generation, and fast temperature rise. Therefore, this structure cannot generally be used in circuit breakers with a current greater than 800A. The existing circuit breakers with current greater than 800A generally use electronic tripping devices, which are composed of current transformers and intelligent controllers. Although they can achieve the function, the cost is greatly increased and the product competitiveness is reduced. Summary of the invention

[0004] To this end, the present invention provides a fault current trigger device suitable for large current (greater than 800A) circuit breakers and a vacuum circuit breaker with the fault current trigger device by improving the structures of an electromagnetic trip trigger and a thermal trip trigger.

[0005] To achieve the above purpose, the technical solution provided by the present invention is as follows:

[0006] A fault current trigger device is used to trigger the tripping of a tripping device, including an electromagnetic tripping trigger and a thermal tripping trigger, wherein the electromagnetic tripping trigger includes: a yoke, an armature, a push rod and a damping member, wherein the yoke is sleeved on the outer peripheral side of a terminal block and has an opening, the armature is directly opposite to the opening of the yoke, and is parallel to and has a certain gap with the opening of the yoke, the damping member applies a resistance to the armature to prevent it from moving toward the yoke, the push rod is fixedly connected to the armature and corresponds to the traction rod of the tripping device; the thermal tripping trigger includes a magnetic induction heating component arranged on the terminal block and a bimetallic strip connected to the magnetic induction heating component, and the bimetallic strip corresponds to the traction rod of the tripping device.

[0007] Furthermore, the opening of the yoke is arranged downward, and the armature is located below the opening of the yoke.

[0008] Furthermore, the push rod is vertically arranged, and the traction rod of the tripping device is directly opposite to the upper end of the push rod.

[0009] Furthermore, a clearance hole corresponding to the push rod is opened on the yoke, the push rod is inserted into the clearance hole of the yoke, and its upper end is exposed from the upper surface of the yoke, and the traction rod of the tripping device is located above the upper surface of the yoke.

[0010] Furthermore, a resistance part having an outer diameter larger than the aperture of the yoke's clearance hole is fixed to the upper end of the push rod, and the armature is suspended, and the armature and the push rod are positioned by the resistance part contacting the upper surface of the yoke.

[0011] Furthermore, the abutment portion is a nut, and the nut is screwed to the upper end of the push rod.

[0012] Furthermore, the damping member is an elastic damping member, and the elastic damping member applies an elastic resistance to the armature to prevent the armature from moving toward the yoke.

[0013] Furthermore, the elastic damping member is a spring, which is sleeved on the top rod, and has two ends respectively abutting against the yoke and the armature.

[0014] Furthermore, the bimetallic strip extends between the upper surface of the yoke and the traction rod.

[0015] Furthermore, the magnetic induction heating component includes: a magnet, a magnetic resistance sheet and a thermal element. The magnet is in a U-shaped structure and is sleeved on the outer peripheral side of the terminal board. The magnetic resistance sheet is fixedly connected to the opening of the magnet, thereby forming an annular magnetic conductive structure. The thermal element is in an annular structure and is sleeved on the outer peripheral side of the magnetic resistance sheet. The bimetallic strip is connected to the thermal element.

[0016] The present invention also provides a vacuum circuit breaker, comprising an electromagnet, a connecting rod assembly, a vacuum arc chamber, a tripping device and the above-mentioned fault current triggering device, wherein the electromagnet is parallel to the vacuum arc chamber and forms a transmission connection through the connecting rod assembly, the tripping device comprises a tripping mechanism and a traction rod, the tripping mechanism is connected in series to the connecting rod assembly, the fault current triggering device is located between the electromagnet and the vacuum arc chamber, and is arranged on a terminal board connected to the moving end of the vacuum arc chamber, and the traction rod is arranged between the fault current triggering device and the triggering end of the tripping mechanism.

[0017] Furthermore, the connecting rod assembly includes a rotating bracket and a push rod, the rotating bracket can rotate around a fulcrum, the electromagnet is connected to one end of the rotating bracket through the push rod, the other end of the rotating bracket is connected to the moving end of the vacuum arc chamber, the moving end and the static end of the vacuum arc chamber are respectively connected to a terminal block, and the extension directions of the two terminal blocks are parallel to the axial direction of the push rod.

[0018] Furthermore, the tripping mechanism is connected in series to the push rod.

[0019] The technical solution provided by the present invention has the following beneficial effects:

[0020] In the electromagnetic trip trigger, the armature is parallel to the opening of the yoke, and the gaps between the two are equal at all positions. The induced magnetic field is generated around the energized wiring board, and the magnetic lines of force in the magnetic field are concentrated in the high-permeability yoke and armature. When the current increases to a certain value, the magnetic field strength increases, and the magnetic field force generated overcomes the resistance applied by the damping member to attract the armature, causing the armature to translate. The translation of the armature drives the top rod to move and hit the traction rod; the magnetic induction heating component of the thermal trip trigger generates heat through the induced magnetic field generated by the wiring board current. The electromagnetic trip trigger and the thermal trip trigger are both set on the wiring board, which does not affect the current transmission of the wiring board. They can be well applied to circuit breakers with large currents (greater than 800A current), and have good accuracy and high reliability. Now, the high-current circuit breaker can be triggered to trip by thermal magnetic means, which solves the difficulty of controlling the temperature rise of the main circuit and increasing the temperature of the bimetallic strip in the thermal trip trigger to ensure tripping in the high-current circuit breaker. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Shown is a schematic structural diagram of a typical fault current triggering device in the prior art;

[0022] Figure 2 The figure is a three-dimensional schematic diagram of a fault current triggering device in an embodiment;

[0023] Figure 3 Shown is a side view of a fault current triggering device in an embodiment;

[0024] Figure 4The figure shows a top view of the fault current triggering device in the embodiment;

[0025] Figure 5 The figure shows a partial structural decomposition schematic diagram of the fault current triggering device in the embodiment;

[0026] Figure 6 The figure shows an assembly diagram of a fault current triggering device in an embodiment assembled on a vacuum circuit breaker;

[0027] Figure 7 Shown Figure 6 Schematic diagram of the structure in the figure;

[0028] Figure 8 The figure shows the internal structure schematic diagram of the vacuum circuit breaker in the embodiment;

[0029] Fig. 9 is a schematic diagram of the trip mechanism in a locked state;

[0030] Fig.10 is a cross-sectional view of the trip mechanism in a locked state;

[0031] Fig.11 is a schematic diagram of the tripping mechanism in a tripping state;

[0032] Fig.12 It is a cross-sectional view of the tripping mechanism in the tripping state. DETAILED DESCRIPTION

[0033] To further illustrate the various embodiments, the present invention provides drawings. These drawings are part of the disclosure of the present invention, which are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, a person of ordinary skill in the art should be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0034] The present invention will now be further described with reference to the accompanying drawings and specific implementation methods.

[0035] Reference Figures 2 to 5 As shown, a fault current trigger device provided in this embodiment is specifically used in a vacuum circuit breaker to trigger the tripping device to trip, one end of the wiring board 11 of the circuit breaker is used to connect the wiring terminal of the load line, and the other end is connected to the moving end of the vacuum interrupter through the flexible connection 12. Of course, in other embodiments, the applicable circuit breaker type is not limited thereto.

[0036] The fault current trigger device includes an electromagnetic trip trigger 20 and a thermal trip trigger 30. The electromagnetic trip trigger 20 includes: a yoke 21, an armature 22, a push rod 24 and a damping member 23. The yoke 21 is sleeved on the outer peripheral side of the terminal block 11 and has an opening (not shown). Specifically, the yoke 21 is a U-shaped structure, and the upper end opening of the U-shaped structure is the opening of the yoke 21. Of course, in other embodiments, the yoke 21 can also be in other structures. The armature 22 is directly opposite to the opening of the yoke 21, and is parallel to the opening of the yoke 21 with a certain gap. The damping member 23 applies a resistance to the armature 22 to prevent it from moving toward the yoke 21. The push rod 24 is fixedly connected to the armature 22 and corresponds to the traction rod of the trip device (such as Figure 8 The corresponding traction rod 72 is shown in the figure). The energized wiring board 11 generates an induced magnetic field at the periphery, and the magnetic lines of force in the magnetic field are concentrated in the high-permeability magnetic yoke 21 and the armature 22. When the current increases to a certain value, the magnetic field strength increases, and the magnetic field force generated overcomes the resistance applied by the damping member 23 to attract the armature 22, causing the armature 22 to translate. The translation of the armature 22 drives the push rod 24 to move and hit the traction rod, thereby triggering the release device to release. The armature 22 is parallel to the opening of the yoke 21, and the gaps at each position between the two are equal, and the precision control is better.

[0037] The thermal trip trigger 30 includes a magnetic induction heating component disposed on the wiring board 11 and a bimetallic strip 34 connected to the magnetic induction heating component, and the bimetallic strip 34 corresponds to the traction rod of the trip device. The magnetic induction heating component of the thermal trip trigger generates heat through the induced magnetic field generated by the current of the wiring board 11, and then transfers the heat to the bimetallic strip 34, so that the bimetallic strip 34 is deformed and hits the traction rod, thereby triggering the tripping action of the trip device.

[0038] The electromagnetic trip trigger 20 and the thermal trip trigger 30 are both arranged on the wiring board 11, which does not affect the current 11 transmission of the wiring board, and can be well applied to circuit breakers with large currents (greater than 800A current), and have good precision and high reliability. Now, the large current circuit breaker can be triggered to trip by means of thermal magnetism, which solves the difficulty of controlling the temperature rise of the main circuit and increasing the temperature of the bimetallic strip 34 in the thermal trip trigger to ensure the tripping in the large current circuit breaker. Compared with the structure of the electronic trip device used in the large current circuit breaker in the prior art, it has low cost, small size and is more competitive in the market.

[0039] Furthermore, in the structure of an actual circuit breaker, the terminal block 11 is a high-voltage part, generally located at the bottom layer, and the upper layer is a switch-on and switch-off operating mechanism, so as to facilitate the operation of the operator and keep the operator away from the high-voltage part. Therefore, the tripping device is generally located above the terminal block 11. Therefore, in this embodiment, the opening of the yoke 21 is set downward, and the armature 22 is located below the opening of the yoke 21. When the yoke 21 attracts the armature 22, the armature 22 translates upward, and drives the top rod 24 to push upward and hit the traction rod of the tripping device. At the same time, the resistance of the attraction between the yoke 21 and the armature 22 also includes the gravity of the armature 22 itself. Such a setting can appropriately reduce the requirements for the damping member 23, which is easier to implement. Of course, in other embodiments, the orientation of the opening of the yoke 21 and the position of the armature 22 can be set according to the actual layout. For example, when the opening of the yoke 21 is set upward, the armature 22 is located above the opening of the yoke 21, and the yoke 21 attracts the armature 22 to move downward. At this time, the resistance of the damping member 23 also has to support the gravity of the armature 22, and the requirements for the damping member 23 are relatively high.

[0040] Furthermore, in this embodiment, the push rod 24 is arranged vertically, and the traction rod of the tripping device is directly opposite to the upper end of the push rod 24. The upward translation of the armature 22 drives the push rod 24 to move upward in the same direction as its axial direction, which can effectively save space. Of course, in other embodiments, the push rod 24 can also be arranged tilted according to the position of the traction rod, as long as the push rod 24 can hit the traction rod.

[0041] Furthermore, in this embodiment, the yoke 21 is provided with a clearance hole (not shown) corresponding to the push rod 24, the push rod 24 is inserted into the clearance hole of the yoke 21, and its upper end is exposed from the upper surface of the yoke 21, and the traction rod of the tripping device is located above the upper surface of the yoke 21. In this way, the push rod 24 can be fixed to the middle position of the armature 22, saving assembly volume and having a better striking effect on the traction rod. Of course, in other embodiments, the push rod 24 can also be set on the periphery of the yoke 21, etc.

[0042] Furthermore, in this embodiment, the upper end of the push rod 24 is also fixed with a contact portion 25 whose outer diameter is larger than the aperture of the clearance hole of the yoke 21, and the armature 22 is suspended, and the armature 22 and the push rod 24 are positioned by the contact portion 25 contacting the upper surface of the yoke 21. No other supporting structure is needed to support the armature, which greatly saves parts, has a simple structure, and is cleverly designed. Of course, in other embodiments, other supporting structures can also be used to support the armature.

[0043] Furthermore, in this embodiment, the abutment 25 is a nut, and the nut 25 is screwed to the upper end of the push rod 24, so that the nut 25 can be moved and adjusted along the axial direction of the push rod 24, thereby adjusting the initial gap between the yoke 21 and the armature 22, and then adjusting the impact displacement of the push rod 24. Of course, in other embodiments, the abutment can also adopt other structures that can be moved and adjusted along the axial direction of the push rod 24, or a structure that is directly fixed to the push rod 24, etc.

[0044] Furthermore, in this embodiment, the damping member 23 is an elastic damping member, and the elastic damping member 23 applies an elastic resistance to the armature 22 to prevent it from moving toward the yoke 21. When the yoke 21 and the armature 22 are attracted to each other, the armature 22 overcomes the elastic resistance of the elastic damping member 23 and moves upward. When the magnetic field force decreases or disappears, the elastic damping member 23 restores the elastic deformation and drives the armature 22 to reset, thereby achieving repeatability. Of course, in other embodiments, the damping member 23 can also be a non-elastic resistance, such as the friction resistance generated by the contact between the armature 22 and the external structure.

[0045] Furthermore, in this embodiment, the elastic damping member 23 is a spring, and the spring 23 is sleeved on the top rod 24, and the two ends of the spring 23 respectively contact the yoke 21 and the armature 22. The spring 23 can be directly sleeved on the top rod 24, which is easy to assemble and has a stable structure after assembly. Of course, in other embodiments, other elastic devices can also be used.

[0046] Furthermore, in this embodiment, in the electromagnetic trip trigger 20, it is generally required that 8 times Ir cannot act, and 10 times Ir can act reliably, which is relatively easy to achieve for a circuit breaker with a small current. However, for a circuit breaker with a large current: if the normal current is 1250A, the effective value of 8 times the current is 10000A, and the effective value of 10 times the current is 12500A, which causes the magnetic conductivity of the yoke 21 and the armature 22 to be in a saturated state long ago. Even if the current increases from 8 times to 10 times, the difference in the change of the magnetic flux of the yoke 21 and the armature 22 is very small, that is, the difference between the action value and the fixed value is very small. It is difficult to be accurate and reliable by the setting of the spring 23 alone, resulting in low reliability of the electromagnet. Therefore, when designing the structure, this problem is fully taken into consideration, and the air gap and magnetic conductivity area of ​​the yoke 21 and the armature 22 can be matched and optimized to increase the difference between the action value and the fixed value to ensure the reliability of the electromagnet action.

[0047] Furthermore, in this embodiment, the bimetallic strip 34 extends between the upper surface of the yoke 21 and the traction rod. When the bimetallic strip 34 reaches a certain temperature, the bimetallic strip 34 deforms and tilts upward to hit the traction rod.

[0048] More specifically, in this embodiment, the magnetic induction heating assembly includes: a magnet 31, a magnetic resistance sheet 32 ​​and a thermal element 33. The magnet 31 is in a U-shaped structure and is sleeved on the outer peripheral side of the wiring board 11. The magnetic resistance sheet 32 ​​is fixedly connected to the opening of the magnet 31 to form an annular magnetic conductive structure. The thermal element 33 is in an annular structure and is sleeved on the outer peripheral side of the magnetic resistance sheet 32. The bimetallic strip 34 is connected to the thermal element 33. The periphery of the energized wiring board 11 generates an induced magnetic field, and the magnetic lines of force in the magnetic field are concentrated on the annular magnetic conductive structure composed of the magnet 31 and the magnetic resistance sheet 32 ​​to form a closed magnetic conductive loop, which is equivalent to the coil of a transformer. At the same time, the thermal element 33 forms a closed loop around the magnetic resistance sheet 32, which is equivalent to the secondary winding of the transformer. Since the thermal element 33 does not output power to the outside, the induced electromotive force it generates is used for heat generation, that is, the magnetic energy is converted into thermal energy, so that the thermal element 33 is heated, and the heat generated by the thermal element 33 is transferred to the bimetallic strip 34 to deform it.

[0049] More specifically, in the present embodiment, a plurality of magnetoresistive sheets 32 are provided and stacked in sequence, which is equivalent to a plurality of magnetoresistive sheets connected in series. The alternating current phenomenon causes eddy currents (iron losses) to be generated on the magnetoresistive sheet, and also causes the temperature of the magnetoresistive sheet 32 ​​to increase, so that the heat can be transferred to the thermal element 33, and the thermal element 33 heats up faster, and the trigger response is faster.

[0050] Specifically, the bimetallic strip 34 is a device in the prior art for triggering a tripping action by heating and deforming. A screw 35 is provided at the end of the bimetallic strip 34 corresponding to the traction rod. When the bimetallic strip 34 is deformed, the traction rod is hit by the screw 35. This is a conventional structure and will not be described in detail here.

[0051] More specifically, in this embodiment, the thermal element 33 is made of pure copper, which has good thermal conductivity and can effectively transfer the temperature on the magnetic resistance plate 32 and the thermal element 33 to the bimetallic strip 34. When the bimetallic strip 34 is deformed, the screw 35 on the bimetallic strip 34 moves accordingly, pushing the traction rod to move, and the circuit breaker can be tripped.

[0052] More specifically, in this embodiment, the thermal element 33 and the magnetic resistance piece 32 are fixedly connected by a connecting column 37 fixedly arranged therebetween, and the structure is simple. Of course, in other embodiments, the thermal element 33 and the magnetic resistance piece 32 can also be fixed by other means.

[0053] The structure of this thermal trip trigger controls the heat generation on the magnetic resistance sheet and the thermal element, and basically does not increase the heat generation of normal circuit components such as the terminal block and flexible connection. It effectively controls the overall temperature rise of the circuit breaker, increases the capacity of the product, reduces the cost of the product, and improves the competitiveness of the product.

[0054] Specific reference Figures 6 to 8As shown, this embodiment also provides a vacuum circuit breaker, including an electromagnet 50, a connecting rod assembly, a vacuum interrupter 40, a tripping device and the above-mentioned fault current triggering device, the electromagnet 50 is arranged in parallel with the vacuum interrupter 40, and is connected to the connecting rod assembly through a transmission connection, the tripping device includes a tripping mechanism 71 and a traction rod 72, the tripping mechanism 71 is connected in series to the connecting rod assembly, the fault current triggering device is located between the electromagnet 50 and the vacuum interrupter 40, and is arranged on the terminal board 11 connected to the moving end of the vacuum interrupter 40, the Figure 8 The wiring board 11 in Figures 2 to 5 The terminal block 11 can fully utilize the gap between the electromagnet 50 and the vacuum interrupter 40, making the structure more compact.

[0055] The traction rod 72 is arranged between the fault current trigger device and the trigger end of the tripping mechanism 71. When the fault current trigger device is actuated to hit the traction rod 72, the traction rod 72 is actuated to act on the trigger end of the tripping mechanism 71, thereby triggering the tripping mechanism 71 to trip. Specifically, the tripping mechanism 71 and the traction rod 72 of the tripping device are both prior art, and their specific structures are not described in detail here.

[0056] More specifically, the connecting rod assembly includes a rotating bracket 61 and a push rod 62. The rotating bracket 61 can rotate around a fulcrum. The electromagnet 50 is connected to one end of the rotating bracket 61 through the push rod 62. The other end of the rotating bracket 61 is connected to the moving end of the vacuum interrupter 40. The electromagnet 50 pushes the push rod 62, thereby driving the rotating bracket 61 to rotate. The rotation of the rotating bracket 61 drives the moving end of the vacuum interrupter 40 to move and close the circuit.

[0057] The moving end and the static end of the vacuum interrupter 40 are respectively connected to a wiring board, that is, the wiring board connected to the moving end is the wiring board 11 for setting the fault current trigger device; the static end is connected to the wiring board 111. The extension directions of the two wiring boards 11, 111 are parallel to the axial direction of the push rod 62, so that the main structure of the vacuum circuit breaker and the overall structure after the vacuum circuit breaker is connected with the external device (such as the isolation contact) are more compact.

[0058] More specifically, the tripping mechanism 71 is connected in series to the push rod 62, that is, the push rod 62 is divided into two sections of support rods, and the tripping mechanism 71 is connected in series between the two sections of support rods, which is convenient for setting the tripping mechanism 71 and performing the tripping action. Of course, in other embodiments, the setting position of the tripping mechanism 71 is not limited to this.

[0059] For more details, please refer to Figures 8 to 11The push rod 62 is divided into two sections of support rods, namely a first section support rod 201 and a second section support rod 204. The tripping mechanism 71 includes a first connecting rod 202, a second connecting rod 203 and a mounting plate. The first section support rod 201, the first connecting rod 202, the second connecting rod 203 and the second section support rod 204 are hingedly connected in sequence. The second section support rod 204 is fixedly connected to the mounting plate and is opposite to the electromagnet 50. A stop rod 206 and a tripping half shaft 205 are assembled on the mounting plate. The stop rod 206 is equipped with a stop rod reset torsion spring, and the tripping half shaft 205 is equipped with a tripping half shaft reset torsion spring.

[0060] In the normal working state of the circuit breaker, if Fig. 9 and Fig.10 As shown, the stop rod 206 presses the second connecting rod 203 under the action of the stop rod reset torsion spring, so that the first connecting rod 202 and the second connecting rod 203 are in a relatively straight state, and the tripping half shaft 205 presses the stop rod 206 under the action of the tripping half shaft reset torsion spring, thereby locking the stop rod 206. At this time, the tripping mechanism 71 is in a locked state, and the electromagnet 50 can push the second section support rod 204 to move the push rod 62 as a whole, thereby pushing the rotating bracket 61 to rotate, and then the moving and static ends of the vacuum interrupter 40 are in contact and closed. When the circuit breaker is normally powered off, the tripping mechanism 71 remains in the locked state.

[0061] When a short circuit or overload fault occurs in the circuit breaker, the current trigger device hits the traction rod 72, and the traction rod 72 moves the tripping half shaft 205, thereby releasing the restriction on the stop rod 206, and the reset spring automatically shortens to pull the rotating bracket in the direction of the electromagnet 50. The rotating bracket 61 rotates around the fulcrum under the action of the reset spring, and the first section of the support rod 201 is pushed by the upper end of the rotating bracket 61 to push the first connecting rod 202, and the second connecting rod 203 overcomes the pressure of the stop rod 206 and rotates, so that the first connecting rod 202 and the second connecting rod 203 are switched from a relatively straight state to a state as shown in the figure. Fig.11 and Fig.12 In the folded state shown, the tripping mechanism 71 enters the tripping state. At the same time, the lower end of the rotating bracket pulls the moving end of the vacuum interrupter 40 to separate the moving and static ends, thereby tripping the circuit breaker.

[0062] Although the present invention has been specifically shown and described in conjunction with the preferred embodiments, it should be understood by those skilled in the art that various changes may be made to the present invention in form and details without departing from the spirit and scope of the present invention as defined by the appended claims, all of which are within the scope of protection of the present invention.

Claims

1. A fault current triggering device, used to trigger the tripping of a tripping device, including an electromagnetic tripping trigger and a thermal tripping trigger, Features: The electromagnetic trip trigger includes: a yoke, an armature, a push rod and a damping member. The yoke is sleeved on the outer peripheral side of the terminal block and has an opening. The armature is opposite to the opening of the yoke and has a certain gap with the opening of the yoke and is parallel to each other. The damping member applies a resistance to the armature to prevent it from moving toward the yoke. The push rod is fixedly connected to the armature and corresponds to the traction rod of the trip device. The thermal trip trigger includes a magnetic induction heating component arranged on the terminal block and a bimetallic strip connected to the magnetic induction heating component, and the bimetallic strip corresponds to the traction rod of the trip device. The magnetic induction heating component of the thermal trip trigger generates heat through the induced magnetic field generated by the current of the terminal block, and then transfers the heat to the bimetallic strip, so that the bimetallic strip is deformed and hits the traction rod, thereby triggering the tripping action of the trip device.

2. The fault current triggering device according to claim 1, Features: The opening of the magnetic yoke is arranged downward, and the armature is located below the opening of the magnetic yoke.

3. The fault current triggering device according to claim 2, Features: The push rod is arranged vertically, and the traction rod of the tripping device is directly opposite to the upper end of the push rod.

4. The fault current triggering device according to claim 3, Features: The yoke is provided with a clearance hole corresponding to the push rod, the push rod is inserted into the clearance hole of the yoke, and its upper end is exposed from the upper surface of the yoke, and the traction rod of the tripping device is located above the upper surface of the yoke.

5. The fault current triggering device according to claim 4, Features: The upper end of the push rod is also fixed with an abutment portion whose outer diameter is larger than the aperture of the yoke's clearance hole. The abutment portion is a nut. The armature is suspended in the air. The nut is screwed to the upper end of the push rod. The armature and the push rod are positioned by the nut abutting against the upper surface of the yoke.

6. The fault current triggering device according to claim 1, Features: The damping member is an elastic damping member, which applies an elastic resistance to the armature to prevent the armature from moving toward the yoke.

7. The fault current triggering device according to claim 6, Features: The elastic damping member is a spring, which is sleeved on the top rod, and has two ends which respectively abut against the yoke and the armature.

8. The fault current triggering device according to claim 4, Features: The bimetal strip extends between the upper surface of the yoke and the drawbar.

9. The fault current triggering device according to claim 1 or 8, Features: The magnetic induction heating component includes: a magnetizer, a magnetic resistance sheet and a thermal element. The magnetizer is in a U-shaped structure and is sleeved on the outer peripheral side of the terminal board. The magnetic resistance sheet is fixedly connected to the opening of the magnetizer to form an annular magnetic conductive structure. The thermal element is in an annular structure and is sleeved on the outer peripheral side of the magnetic resistance sheet. The bimetallic strip is connected to the thermal element.

10. A vacuum circuit breaker, Features: It comprises an electromagnet, a connecting rod assembly, a vacuum arc chamber, a tripping device and a fault current triggering device as described in any one of claims 1 to 9, wherein the electromagnet is parallel to the vacuum arc chamber and forms a transmission connection through the connecting rod assembly, the tripping device comprises a tripping mechanism and a traction rod, the tripping mechanism is connected in series to the connecting rod assembly, the fault current triggering device is located between the electromagnet and the vacuum arc chamber, and is arranged on a terminal board connected to the moving end of the vacuum arc chamber, and the traction rod is arranged between the fault current triggering device and the triggering end of the tripping mechanism.

11. The vacuum circuit breaker according to claim 10, Features: The connecting rod assembly includes a rotating bracket and a push rod. The rotating bracket can rotate around a fulcrum. The electromagnet is connected to one end of the rotating bracket through the push rod. The other end of the rotating bracket is connected to the moving end of the vacuum arc chamber. The moving end and the static end of the vacuum arc chamber are respectively connected to a wiring board. The extension directions of the two wiring boards are parallel to the axial direction of the push rod.

12. The vacuum circuit breaker according to claim 11, Features: The tripping mechanism is connected in series to the push rod.

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