A circuit breaker transient test circuit and contact protection method

Abstract

The application discloses a circuit breaker transient test loop and contact protection method, which belongs to the field of circuit breakers and comprises a magnetic system, a first current receiving device and a second current receiving device. The first current receiving device and the second current receiving device are used for receiving test current during transient test, and the loop is used for testing the magnetic system. Thus, the application redesigns the loop for transient test of the circuit breaker, directly transmits the current through the current receiving device to the magnetic system for transient test, and makes the current not flow through the moving contact during the transient test, that is, the moving contact and the static contact are not in contact. In this way, the generation of arc is avoided during the transient test, the damage of the contact caused by the transient test is eliminated, the static contact and the moving contact are protected, and the service life of the product is prolonged.

Description

Technical Field

[0001] This application relates to the field of circuit breakers, and in particular to a circuit breaker instantaneous test circuit and contact protection method. Background Technology

[0002] According to product manufacturing standards, the magnetic system in each circuit breaker must be instantaneously tested before it leaves the factory to test the circuit breaker's sensitivity.

[0003] In existing technologies, such as Figure 1 As shown, during the instantaneous test of the circuit breaker, the current flows through terminal block A, the moving contact, the stationary contact, the magnetic system, and terminal block B to form a circuit. During the instantaneous test, terminal blocks A and B conduct upon receiving the test current, allowing the current to flow through the moving and stationary contacts to the magnetic system. Upon receiving the test current, the coil in the magnetic system generates a magnetic field. This magnetic field causes the iron core in the magnetic system to push the unlocking mechanism, separating the moving and stationary contacts. When the moving and stationary contacts separate, an electric arc is generated between them. This arc can burn the moving and stationary contacts, and severe burns can lead to an excessively high temperature rise in the circuit breaker.

[0004] Therefore, how to prevent the generation of electric arcs during instantaneous testing and protect the contacts is a key issue of concern to those skilled in the art. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a circuit breaker instantaneous test circuit and contact protection method to achieve arc-free operation during instantaneous testing and to protect the contacts.

[0006] The embodiments of this application disclose the following technical solutions:

[0007] In a first aspect, the circuit includes a magnetic system, a first current receiving device, and a second current receiving device. The first current receiving device and the second current receiving device are used to receive the test current during instantaneous testing, and the circuit is used to test the magnetic system.

[0008] Optionally, the circuit further includes a test device, a first end of which is connected to a first end of the first current receiving device, and a second end of which is connected to a first end of the second current receiving device. The test device is used to provide a test current for instantaneous testing.

[0009] Optionally, the test equipment includes a battery.

[0010] Optionally, the circuit further comprises a static contact, a first end of the static contact being connected with a second end of the first current receiving device, a second end of the static contact being connected with a first end of the magnetic system, a second end of the magnetic system being connected with a second end of the second current receiving device, the static contact being used for making the test current flow to the magnetic system.

[0011] Optionally, the static contact and the magnetic system are both fixed inside a circuit breaker to which the circuit is applied.

[0012] Optionally, the circuit breaker further comprises a moving contact, in the circuit breaker, the moving contact is in a separated state with the static contact.

[0013] Optionally, the moving contact is fixed inside a circuit breaker to which the circuit is applied.

[0014] Optionally, the current receiving device comprises a terminal block.

[0015] In a second aspect, a contact protection method comprises:

[0016] receiving a test current signal;

[0017] transmitting the current signal according to a preset current path for protecting a contact, the preset current path for protecting a contact being composed of the magnetic system, the first current receiving device and the second current receiving device.

[0018] Optionally, after the receiving of the test current signal, the method further comprises:

[0019] in response to the current signal being greater than a preset current threshold, performing the step of transmitting the current signal according to the preset current path for protecting a contact.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] The present application redesigns a circuit for performing a test on a circuit breaker, and transmits a current through a current receiving device directly to a magnetic system to perform a test, so that the current does not flow through a moving contact during the test, that is, the moving contact and the static contact are not in contact. In this way, during the test, the generation of an arc is avoided, the damage of a contact point caused by the test is eliminated, the static contact and the moving contact are protected, and the service life of the product is prolonged. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the accompanying drawings in the following description only represent some embodiments of the present application, and for those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0023] Figure 1 Connection relationship diagram of the existing circuit breaker transient test circuit;

[0024] Figure 2 Connection relationship diagram of the circuit breaker transient test circuit provided by the embodiments of the present application;

[0025] Figure 3 Current flow direction diagram of the circuit breaker transient test circuit provided by the embodiments of the present application;

[0026] Figure 4 Current flow direction diagram of the existing circuit breaker transient test circuit;

[0027] Figure 5 Flow chart of the contact protection method provided by the embodiments of the present application. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments only represent some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort fall within the protection scope of the present application.

[0029] It should be noted that the circuit breaker transient test circuit and the contact protection method provided by the present application are used in the field of circuit breakers, and the above are only examples, and do not limit the application field of the method and device provided by the present application.

[0030] As described above, in the prior art, Figure 1As shown, when the circuit breaker is performing the transient test, the current forms a loop through the terminal block A, the movable contact, the static contact, the magnetic system and the terminal block B. During the transient test, the terminal block A and the terminal block B are turned on after receiving the test current, so that the test current flows through the movable contact and the static contact to the magnetic system. After receiving the test current, the coil in the magnetic system generates a magnetic field, which pushes the iron core in the magnetic system to drive the unlocking mechanism to separate the movable contact from the static contact, that is, the test current is disconnected by separating the movable contact from the static contact. When the movable contact and the static contact are separated at the connection position, an arc is generated between the movable contact and the static contact, which causes burn of the movable contact and the static contact, and the burn is serious, which also causes high temperature rise of the circuit breaker. It should be noted that the movable contact is connected with the static contact after receiving the test current, so that the test current flows to the static contact and then flows to the magnetic system. Therefore, how to generate no arc during the transient test and how to protect the contacts are the key problems for those skilled in the art.

[0031] Therefore, the inventors propose the technical scheme of the present application, which redesigns the loop for performing the transient test on the circuit breaker, directly transmits the current to the magnetic system through the current receiving device for the transient test, so that the current does not flow through the movable contact during the transient test, that is, the movable contact and the static contact are not in contact. In this way, the generation of the arc is avoided during the transient test, the damage of the contacts caused by the transient test is eliminated, the static contact and the movable contact are protected, and the service life of the product is prolonged. Moreover, after the transient test is completed, the test current is directly disconnected by the test device providing the test current to the current receiving device, and the test current is not disconnected by driving the movable contact and the static contact to separate.

[0032] Next, the meanings of the terms that may be involved in the present specification are introduced.

[0033] Circuit breaker: refers to a switching device capable of closing, carrying and opening the current under normal loop conditions, and capable of closing, carrying and opening the current under abnormal loop conditions within a specified time.

[0034] Circuit breaker contact: the circuit breaker contact is an important component of the circuit breaker, the switch cabinet, the disconnector and the grounding switch, and its performance directly affects the quality and service life of the electric appliance.

[0035] In order to enable those skilled in the art to better understand the present application scheme, the present application is further described in detail below in combination with the drawings and specific embodiments.

[0036] Referring to Figure 2 , Figure 2 The connection relationship diagram of the circuit breaker transient test loop of the present application provided for the embodiments of the present application is shown in Figure 2 as shown in

[0037] The circuit breaker transient test circuit of the present application comprises a magnetic system, a first current receiving device and a second current receiving device, wherein the first current receiving device and the second current receiving device are used to receive test current during transient test, and the circuit is used to test the magnetic system in the circuit breaker.

[0038] Further, the test circuit further comprises a test device, and the first end of the first current receiving device and the first end of the second current receiving device are connected with the test device respectively to receive test current provided by the test device and make the test current conductive. The following will be explained in combination with a specific example. In the example, the test device is a battery, the current receiving device is a terminal block, one end of the first terminal block is connected with one end of the battery, the other end of the first terminal block is connected with a static contact, one end of the second terminal block is connected with the other end of the battery, and the other end of the second terminal block is connected with the magnetic system. During the test, the first terminal block and the second terminal block are connected with the battery at the same time to make the test current conductive and test the magnetic system.

[0039] Further, the test circuit further comprises a static contact, which is used to make the test current conductive to flow to the magnetic system. The second end of the first current receiving device is connected with the first end of the static contact, the second end of the static contact is connected with the first end of the magnetic system, and the second end of the magnetic system is connected with the second end of the second current receiving device to form the test circuit. And during the transient test, the moving contact does not contact with the static contact to prevent the current passing between the static contact and the moving contact.

[0040] In other embodiments, the circuit breaker transient test circuit can only comprise a test device, a magnetic system, a first current receiving device and a second current receiving device. Specifically, the first end of the test device is connected with the first end of the first current receiving device, the second end of the test device is connected with the first end of the second current receiving device, the second end of the first current receiving device is connected with the first end of the magnetic system, and the second end of the magnetic system is connected with the second end of the second current receiving device to form the transient test circuit for testing the magnetic system.

[0041] Further, in the circuit breaker to which the test circuit is applied, a movable contact is further included, and the movable contact is in a separated state from the fixed contact, at which time the test circuit is in an arcless state. It can be understood that, in the prior art, because the movable contact and the fixed contact are often in a contact (current flow) state during the instantaneous test, an arc is generated between the movable contact and the fixed contact, which causes serious burn of the movable contact and the fixed contact. Therefore, the present application proposes that the test current directly flows to the magnetic system after passing through the fixed contact, which can prevent the movable contact and the fixed contact from being in the contact state, and can prevent the arc from being generated between the movable contact and the fixed contact, thereby protecting the movable contact and the fixed contact, and further prolonging the service life of the product during the instantaneous test. Therefore, when the movable contact and the fixed contact are in the separated state, the circuit breaker instantaneous test circuit is in the arcless state, and the contact damage caused by the arc is also prevented. It is also found by the inventor that the instantaneous test is essentially a test of the electromagnetic system, and therefore, during the instantaneous test, the test current can be directly applied to the magnetic system in the state of being separated from the fixed contact, so as to perform the instantaneous test on the magnetic system.

[0042] It should be noted that, in the present alternative, the movable contact can also be connected with the first current receiving device and the magnetic system, and is used to realize the overall function of the circuit breaker during use of the circuit breaker, and the movable contact is not in the current flow state with the fixed contact during the use. Because the movable contact is not used during the instantaneous test, detailed description is not given herein.

[0043] Specifically, the movable contact is connected with the magnetic system through a transmission mechanism, and when the magnetic system receives the test current, the transmission mechanism is driven to drive the movable contact to move. The magnetic system includes a coil, a movable iron core and other elements, and when the magnetic system receives the test current, a magnetic field is generated to drive the movable iron core to move, thereby driving the transmission mechanism to drive the movable contact to move. It should be noted that the connection mode of the movable contact and the magnetic system is the prior art, and detailed description is not given herein.

[0044] As an implementable embodiment, the fixed contact, the movable contact and the magnetic system are all fixed in the circuit breaker to which the instantaneous test circuit is applied. The current receiving device can include a wiring board, and can also include other devices that can contact the power supply.

[0045] Referring to Figure 3 , Figure 3 The current flow direction of the circuit breaker instantaneous test circuit provided by the embodiment of the present application is shown in Figure 3 .

[0046] The test power supply completes the instantaneous test through the first connection point, the fixed contact, the magnetic system and the third connection point, and the first connection point and the third connection point correspond to the first current receiving device and the second current receiving device in Figure 2 , respectively.Figure 3 In this process, the test power supply only flows from the first connection point to the third connection point; it does not flow to the moving contact. This process involves the first connection point connecting to the stationary contact, the stationary contact connecting to the magnetic system, and then the magnetic system connecting to the third connection point. During this process, since the stationary contact is not in contact with the moving contact, no current flows between them, thus preventing the generation of an electric arc and avoiding severe burns to either contact.

[0047] Furthermore, the differences between this application and existing technologies are explained in comparison with prior art; see [link to relevant documentation]. Figure 4 , Figure 4 This is a schematic diagram of the current flow direction in the instantaneous test circuit of a current-limited circuit breaker, such as... Figure 4 As shown:

[0048] The test power supply completes the instantaneous test through a first connection point, a moving contact, a stationary contact, a magnetic system, and a second connection point. Upon receiving the test power supply, the moving contact closes with the stationary contact, forming a current path so that the test power supply flows to the magnetic system. The first and second connection points correspond to... Figure 1 Terminal block A and terminal block B are included. Figure 4 In this process, the test power supply runs through the entire process from the first connection point to the second connection point. This process involves the first connection point connecting to the moving contact, the moving contact connecting to the stationary contact, the stationary contact connecting to the magnetic system, and then the magnetic system connecting to the second connection point. During this process, when the magnetic system receives the test power supply, the moving and stationary contacts disconnect, generating an electric arc between them. This creates a contact break point, and the arc can cause severe burns to both the moving and stationary contacts.

[0049] As can be seen, in this alternative solution, the circuit for instantaneous testing of the circuit breaker has been redesigned. Current is transmitted directly to the magnetic system through a current receiving device for instantaneous testing, ensuring that the current does not flow through the moving contact during the instantaneous test, thus preventing contact between the moving and stationary contacts. This avoids the generation of electric arcs during instantaneous testing, eliminates contact damage caused by the instantaneous test, protects both the stationary and moving contacts, and extends the product's service life.

[0050] The following describes a contact protection method provided in this application through another embodiment.

[0051] See Figure 5 This figure is a flowchart of the contact protection method provided in an embodiment of this application, as shown below. Figure 5 As shown, the method may include:

[0052] S101: Receives the instantaneous test current signal.

[0053] In this step, the current receiving device receives the current signal required for the instantaneous test (the current receiving device is...). Figure 2 The first and second current receiving devices shown in the diagram work together to determine whether the current signal is greater than a preset current threshold. If the current signal is greater than the preset current threshold, step S102 is executed. It should be noted that the current receiving device is a device that receives current signals. The instantaneous test is a functional test performed before the product leaves the factory. This functional test tests the magnetic system in the circuit breaker to detect the sensitivity of the circuit breaker. The current signal is provided by the testing equipment, and the current receiving device can be a terminal block.

[0054] S102: The current signal is transmitted according to the preset current channel of the protective contact.

[0055] In this step, the preset current path of the protective contact consists of a magnetic system and a current receiving device. This current path also includes a stationary contact and a testing device. The stationary contact allows the test current to flow to the magnetic system, and the testing device provides the test current for instantaneous testing. The current path is... Figure 2 The circuit breaker instantaneous test circuit shown is described above. Based on the above description, this application redesigns the circuit breaker instantaneous test circuit. In this circuit breaker instantaneous test circuit, direct current flow between the moving contact and the stationary contact is eliminated. That is, the current does not flow through the moving contact during the instantaneous test, but is directly applied to the magnetic system through the stationary contact. This prevents the generation of an electric arc between the moving and stationary contacts, thus achieving the purpose of protecting both the moving and stationary contacts.

[0056] Understandably, after receiving the current signal, it is transmitted through the preset current path of the protective contact. Since the current signal is directly applied to the magnetic system via the stationary contact in this current path to complete the instantaneous test, and no current flows directly between the moving and stationary contacts in the circuit breaker, no arc is generated between them. Thus, while completing the instantaneous test, the moving and stationary contacts are not affected in any way, achieving arc-free operation and protecting both the moving and stationary contacts during the instantaneous test.

[0057] It should also be noted that in this optional scheme, the moving contact can also be connected to a current receiving device and a magnetic system corresponding to the current signal required for instantaneous testing, so as to realize the overall function of the circuit breaker during its use. Since the moving contact is not used during the instantaneous test, it will not be described in detail here.

[0058] In summary, the optional solution illustrates how to achieve no arc generation and protect the contacts during the instantaneous test. Specifically, in the optional solution, the current channel during the instantaneous test is redesigned, and the static contact, the test device, the magnetic system and the current receiving device are used to form a preset current channel for protecting the contacts, and the current signal is transmitted through the current channel to perform the instantaneous test. In the current channel, the moving contact and the static contact are in a separated state, that is, the current signal does not flow through the moving contact, and only the current signal is directly loaded on the magnetic system through the static contact to complete the instantaneous test. At this time, the current does not pass between the static contact and the moving contact, so that the arc will not be generated between the static contact and the moving contact. Thus, during the instantaneous test, the generation of the arc is avoided, and the burning of the moving contact and the static contact will not occur, the static contact and the moving contact are protected, so that the damage of the contacts caused by the instantaneous test is eliminated, and the service life of the product is prolonged.

[0059] It should be noted that the "first" and "second" in the names of "first" and "second" mentioned in the embodiments of the present application are only used for name identification, and do not represent the first and second in order.

[0060] The above describes in detail the circuit breaker instantaneous test circuit and the contact protection method provided by the present application. The principles and implementation modes of the present application are described by applying specific examples in this paper, and the above description of the embodiments is only used to help understand the method of the present application and its core idea. It should be pointed out that for ordinary skilled persons in the art, some improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A circuit breaker instantaneous test circuit, characterized in that, The circuit includes a magnetic system, a first current receiving device, and a second current receiving device. The first current receiving device and the second current receiving device are used to receive the test current during instantaneous testing. The circuit is used to test the magnetic system. The circuit also includes a testing device, a first end of which is connected to a first end of the first current receiving device, and a second end of which is connected to a first end of the second current receiving device. The testing device is used to provide a test current for instantaneous testing. The circuit further includes a stationary contact, the first end of which is connected to the second end of the first current receiving device, the second end of which is connected to the first end of the magnetic system, and the second end of the magnetic system is connected to the second end of the second current receiving device. The stationary contact is used to allow the test current to flow to the magnetic system. The circuit breaker also includes a moving contact, which is separated from the stationary contact.

2. The instantaneous test circuit for a circuit breaker according to claim 1, characterized in that, The testing equipment includes a battery.

3. The instantaneous test circuit for a circuit breaker according to claim 1, characterized in that, Both the stationary contact and the magnetic system are fixed inside the circuit breaker that uses the circuit.

4. The instantaneous test circuit for a circuit breaker according to claim 1, characterized in that, The moving contact is fixed inside the circuit breaker that uses the circuit.

5. The instantaneous test circuit for a circuit breaker according to claim 1, characterized in that, The current receiving device includes a terminal block.

6. A contact protection method, characterized in that, The circuit breaker instantaneous test circuit according to any one of claims 1 to 5 includes: Receives instantaneous test current signals; The current signal is transmitted according to the preset current channel of the protective contact, which is composed of the magnetic system, the first current receiving device, the second current receiving device, the test equipment, and the stationary contact.

7. The contact protection method according to claim 6, characterized in that, After receiving the instantaneously tested current signal, the method further includes: In response to the current signal being greater than a preset current threshold, the step of transmitting the current signal according to the preset current channel of the protective contact is performed.

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