Arc extinguishing relay, arc extinguishing device and arc extinguishing method

Abstract

The present invention discloses an arc extinguishing relay, an arc extinguishing device and an arc extinguishing method, wherein the arc extinguishing relay comprises: a first moving contact, a second moving contact, a first static contact and a second static contact; the first moving contact is attracted or disconnected with the first static contact, and the second moving contact is attracted or disconnected with the second static contact; the first moving contact and the second moving contact are connected in parallel, the first static contact is connected with the second static contact through a surge current suppression device, and when the armature pulls the first moving contact and the second moving contact to attract the first static contact and the second static contact respectively, the time when the first moving contact reaches the first static contact is inconsistent with the time when the second moving contact reaches the second static contact. The present invention reduces the impact of the surge current on the relay contacts by strictly inconsistent the time when the two moving contacts reach the two static contacts under the attraction of the armature, and first connects and then shorts the surge suppression device, thereby extending the service life of the relay contacts.

Description

Technical Field

[0001] The invention relates to the field of relays, and in particular to an arc extinguishing relay, an arc extinguishing device and an arc extinguishing method. Background Art

[0002] A relay is an automatic switch that uses a smaller current and a lower voltage to control a larger current and a higher voltage. This switching function is achieved by means of an electromagnet installed inside. A small current is passed through the electromagnet coil to generate a magnetic field. The magnetic field is used to loosen or attract the armature, which in turn drives the spring sheets to attract or disconnect, thereby turning the load circuit on or off. However, in the process of controlling the on and off of the load, arcs will be generated at the load end at the moment of disconnection or connection. These arcs affect the life of the relay contacts, so they need to be as controllable as possible.

[0003] The load characteristics connected to the relay are generally divided into resistive load, capacitive load and inductive load. Different load characteristics have different effects on the life of the relay contacts. Resistive load has little effect on the life of the relay contacts; inductive load affects the life of the relay contacts due to the high voltage generated by the reverse induced electromotive force at the moment the relay is disconnected; capacitive load affects the life of the relay contacts due to the impact of large current at the moment the relay contacts are connected. The above-mentioned capacitive load and inductive load can also use a zero-crossing trigger circuit to extend the service life of the contacts by disconnecting the contacts at the voltage zero point. However, since the time when the relay contacts are disconnected is affected by temperature, altitude, materials, and processes, the actual effect is quite limited. Summary of the invention

[0004] In view of the above technical problems, the purpose of the present invention is to provide an arc extinguishing relay, an arc extinguishing device and an arc extinguishing method to solve the problem that the capacitive load affects the life of the existing relay contacts due to the impact of large current when the existing relay contacts are connected.

[0005] The present invention adopts the following technical solutions:

[0006] An arc-extinguishing relay comprises: a first moving contact, a second moving contact, a first stationary contact and a second stationary contact, wherein the first moving contact is attracted or disconnected with the first stationary contact, and the second moving contact is attracted or disconnected with the second stationary contact; the first moving contact and the second moving contact are connected in parallel, and the first stationary contact is connected with the second stationary contact through a surge current suppression device, and when the first moving contact and the second moving contact are respectively attracted with the first stationary contact and the second stationary contact at the same time, when the first moving contact and the second moving contact are respectively attracted with the first stationary contact and the second stationary contact, the time when the first moving contact reaches the first stationary contact is inconsistent with the time when the second moving contact reaches the second stationary contact.

[0007] Furthermore, the elastic force of the spring sheet used in the first movable contact is different from the elastic force of the spring sheet used in the second movable contact.

[0008] Furthermore, a stroke of the first movable contact to reach the first static contact is shorter than a stroke of the second movable contact to reach the second static contact.

[0009] Furthermore, one or more circular holes or fine grooves are provided on the spring sheet of the first moving contact.

[0010] Furthermore, the size of the set area of ​​the reed of the first movable contact is smaller than the size of the set area of ​​the reed of the second movable contact.

[0011] Furthermore, the thickness of the first moving contact is different from the thickness of the second moving contact.

[0012] Furthermore, the thickness of the first stationary contact is different from the thickness of the second stationary contact.

[0013] Further, a position of the first stationary contact relative to the first movable contact is different from a position of the second stationary contact relative to the second movable contact.

[0014] An arc extinguishing device comprises the arc extinguishing relay, a capacitive load and a power supply, wherein the arc extinguishing relay is connected in series with the capacitive load and the power supply to form a load circuit, wherein a connection point between a first moving contact and a second moving contact of the arc extinguishing relay is connected to one end of the capacitive load, a first static contact of the arc extinguishing relay is connected to one end of the power supply, and a connection point where the first static contact of the arc extinguishing relay is connected to the second static contact via a surge current suppression device is connected to the other end of the power supply.

[0015] An arc extinguishing method, using the arc extinguishing device, comprises:

[0016] When the armature pulls the first moving contact and the second moving contact to engage with the first static contact and the second static contact respectively, the time for the first moving contact to reach the first static contact is less than the time for the second moving contact to reach the second static contact;

[0017] After the first moving contact reaches the first stationary contact and before the second moving contact reaches the second stationary contact, the power supply charges the capacitive load through the surge current suppression device; after the second moving contact reaches the second stationary contact, the surge current suppression device is short-circuited and the power supply continues to charge the capacitive load.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention achieves strict inconsistency in the time when two moving contacts reach two static contacts under the attraction of the armature, and the time difference when two moving contacts reach two static contacts under the attraction of the armature. A surge current suppressor is first connected to reduce the surge current at the moment when the capacitive load is connected, and then the surge current suppressor is short-circuited, thereby greatly reducing the impact of the surge current on the relay contacts, thereby extending the service life of the relay contacts. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of an arc-extinguishing relay embodiment 1 of the present invention when the thickness of the first moving contact is greater than the thickness of the second moving contact;

[0021] Figure 2 It is a structural schematic diagram of an arc-extinguishing relay embodiment 1 of the present invention when the thickness of the first static contact is greater than the thickness of the second static contact;

[0022] Figure 3 A schematic structural diagram of an arc-extinguishing relay embodiment 1 of the present invention, in which the stroke of the first moving contact to the first stationary contact is greater than the stroke of the second moving contact to the second stationary contact due to the different positions of the first stationary contact relative to the first moving contact and the second stationary contact relative to the second moving contact;

[0023] Figure 4 A schematic diagram of the positions of the moving and static contacts and the thickness of the contacts of a conventional relay according to an embodiment of the present invention;

[0024] Figure 5 It is an assembly diagram of an arc-extinguishing relay and an inrush current suppression device in Embodiment 1 of an arc-extinguishing relay of the present invention;

[0025] Figure 6 An equivalent circuit diagram of an arc extinguishing device embodiment of the present invention;

[0026] Figure 7a A schematic diagram of an arc-extinguishing relay embodiment of the present invention in which a thin groove is provided on the reed of the first moving contact;

[0027] Figure 7b A schematic diagram of an arc-extinguishing relay embodiment of the present invention in which one or more circular holes are provided on the reed of the first moving contact;

[0028] Figure 8 A schematic diagram of an arc-extinguishing relay embodiment of the present invention in which the size of the set area of ​​the reed of the first moving contact is smaller than the size of the set area of ​​the reed of the second moving contact;

[0029] Among them, 1. a first moving contact; 2. a second moving contact; 3. a first stationary contact; 4. a second stationary contact; 5. a surge current suppression device. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, under the premise of no conflict, the embodiments or technical features described below can be arbitrarily combined to form a new embodiment:

[0031] Embodiment 1:

[0032] The arc extinguishing relay of the present invention is shown in FIG. Figure 1 As shown, it includes: a first moving contact 1, a second moving contact 2, a first static contact 3, a second static contact 4, the first moving contact 1 and the first static contact 3 are attracted or disconnected, and the second moving contact 2 and the second static contact 4 are attracted or disconnected; specifically, the first moving contact 1 and the second moving contact 2 can be pulled together or disconnected with the first static contact 3 and the second static contact 4 respectively by the armature; the first moving contact 1 and the second moving contact 2 are connected in parallel, and the first static contact 3 is connected to the second static contact 4 through the surge current suppression device 5. When the armature simultaneously pulls the first moving contact 1 and the second moving contact 2 to attract the first static contact 3 and the second static contact 4 respectively, the time when the first moving contact 1 reaches the first static contact 3 is inconsistent with the time when the second moving contact 2 reaches the second static contact 4.

[0033] It should be noted that there is no strict order in which the two moving contacts of a conventional relay reach the two static contacts. Figure 4 As shown, Figure 4 For the position of the moving and static contacts and the thickness of the contacts of conventional relays, under normal conditions, when the armature is attracted, there is no strict order in the time when the two moving contacts reach the two static contacts. In order to ensure that there is a strict order in the time when the two moving contacts reach the two static contacts, the thickness of the contacts or the position of the contacts can be designed.

[0034] Optionally, the elastic force of the reed used in the first moving contact 1 is different from the elastic force of the reed used in the second moving contact 2, which can reduce the elastic reaction force of the moving contact with a short stroke and strengthen the contact pressure of the moving contact with a long stroke to provide better power output for the load.

[0035] Optionally, a stroke of the first movable contact 1 to reach the first stationary contact 3 is smaller than a stroke of the second movable contact 2 to reach the second stationary contact 4 .

[0036] like Figure 3 As shown, Figure 3This is a structural schematic diagram when the stroke of the first moving contact 1 to reach the first static contact 3 is greater than the stroke of the second moving contact 2 to reach the second static contact 4 due to the different positions of the first static contact 3 relative to the first moving contact 1 and the second static contact 4 relative to the second moving contact 2. As can be seen from the figure, the distance of the first static contact 3 relative to the first moving contact 1 is greater than the distance of the second static contact 4 relative to the second moving contact 2, resulting in the stroke of the first moving contact 1 to reach the first static contact 3 being greater than the stroke of the second moving contact 2 to reach the second static contact 4.

[0037] Optionally, the spring sheet of the first movable contact 1 is provided with one or more circular holes or thin grooves. Figure 7a As shown, a thin groove is provided on the spring leaf of the first moving contact 1; Figure 7b As shown, one or more circular holes are provided on the spring leaf of the first movable contact 1 .

[0038] Optionally, the size of the set area of ​​the reed of the first movable contact 1 is smaller than the size of the set area of ​​the reed of the second movable contact 2 .

[0039] like Figure 8 As shown, the size of the set area of ​​the reed of the first movable contact 1 is smaller than the size of the set area of ​​the reed of the second movable contact 2. The set area may be a specific area of ​​the reed.

[0040] In the specific implementation process, Figure 1 As shown, the present invention provides one or more circular holes or fine grooves on the reed of the first moving contact 1, or makes the size of the set area of ​​the reed of the first moving contact 1 smaller than the size of the set area of ​​the reed of the second moving contact 2. These practices are helpful to reduce the reaction force of the reed of the moving contact with a short stroke, thereby reducing the resistance to the subsequent movement of the moving contact with a long stroke.

[0041] Optionally, the thickness of the first moving contact 1 is different from the thickness of the second moving contact 2;

[0042] For example, Figure 1 As shown, the thickness of the first moving contact 1 is greater than the thickness of the second moving contact 2;

[0043] Optionally, the thickness of the first stationary contact 3 is different from the thickness of the second stationary contact 4 .

[0044] For example, Figure 2 As shown, the thickness of the second stationary contact 4 is smaller than the thickness of the first stationary contact 3 .

[0045] It should be noted that the two moving contacts move toward the two static contacts under the traction of the same armature. When they first contact the static contact, the elastic force of the moving contact with a short stroke will react to the traction force of the armature, hindering the moving contact with a longer stroke from continuing to move toward the static contact. Therefore, the two springs that need to be assembled with the moving contact have different elastic forces, reducing the elastic reaction force of the moving contact with a short stroke, and strengthening the contact pressure of the moving contact with a long stroke to provide better power output for the load. In order to achieve this goal, we can open a few tiny round holes or a small groove on the spring of the moving contact with a short stroke, or make it slightly narrower than the other spring in a specific area. These will help reduce the reaction force of the spring of the moving contact with a short stroke and reduce resistance to the subsequent movement of the moving contact with a long stroke.

[0046] The assembly diagram of the arc extinguishing relay and the surge current suppression device 5 when connected can be referred to as follows Figure 5 As shown, the first stationary contact 3 is connected to the second stationary contact 4 through a surge current suppression device 5 .

[0047] In the above implementation process, the time when the two moving contacts reach the static contact under the traction of the same armature mechanism has a strict sequence due to the different thicknesses or positions of the contacts. Therefore, it can accurately ensure the accurate connection and short-circuit of the surge current suppression device 5 to complete the surge current suppression and load power supply work.

[0048] It should be noted that the surge current suppression device 5 is a purely resistive fixed resistor or a power PTC or NTC whose resistance varies with temperature.

[0049] In the above implementation process, the two moving contacts move toward the static contact under the traction of the same electromagnet, and the moving contact with a shorter stroke first contacts its corresponding static contact, and the inrush current suppression device 5 is first connected to the capacitive load circuit. Due to its certain resistance, under the same voltage environment, its surge current changes from the infinite value of the initial transient short circuit to the limited current under the action of the inrush current suppression device 5, and charges the capacitive load. Later, the other group of contacts with a longer stroke closes, short-circuiting the inrush current suppression device 5 and supplying normal power to the capacitive load, which greatly reduces the short-circuit impact of the surge current on the relay contacts, thereby extending the service life of the relay.

[0050] Embodiment 2:

[0051] The present invention adopts an arc extinguishing device using an arc extinguishing relay, such as Figure 6As shown, it includes an arc-extinguishing relay, a capacitive load and a power supply. The arc-extinguishing relay includes: a first moving contact 1, a second moving contact 2, a first static contact 3, a second static contact 4, and the first moving contact 1 and the second moving contact 2 are respectively attracted or disconnected with the first static contact 3 and the second static contact 4 through an armature; the first moving contact 1 and the second moving contact 2 are connected in parallel, and the first static contact 3 is connected with the second static contact 4 through a surge current suppression device 5. When the armature pulls the first moving contact 1 and the second moving contact 2 to attract the first static contact 3 and the second static contact 4 respectively, the time when the first moving contact 1 reaches the first static contact 3 is inconsistent with the time when the second moving contact 2 reaches the second static contact 4.

[0052] like Figure 6 As shown, the arc-extinguishing relay is connected in series with a capacitive load and a power supply to form a load circuit, wherein a connection point between the first moving contact 1 and the second moving contact 2 of the arc-extinguishing relay is connected to one end of the capacitive load, a first static contact 3 of the arc-extinguishing relay is connected to one end of the power supply, and a connection point where the first static contact 3 of the arc-extinguishing relay is connected to the second static contact 4 through a surge current suppression device 5 is connected to the other end of the power supply.

[0053] In the above implementation process, the time when the two moving contacts reach the two static contacts under the attraction of the armature is strictly inconsistent. Through the time difference between the two moving contacts reaching the two static contacts, a surge current suppressor is first connected to reduce the surge current at the moment the capacitive load is connected and charge the capacitive load, and then the surge current suppressor is short-circuited, and the contacts of the short-circuited surge current suppressor are used to power the subsequent load.

[0054] The working principle of an arc extinguishing device using an arc extinguishing relay of the present invention is as follows:

[0055] Under the traction of the same action armature, the two moving contacts connected in parallel move toward the static contact, and the moving contact with the shorter stroke first contacts its corresponding static contact, such as Figure 6As shown, the surge current suppression device 5 is first connected to the capacitive load circuit. Since it has a certain resistance, under the same voltage environment, its surge impact current changes from the infinite current of the initial transient short circuit to a limited current under the action of the surge current suppression device 5. Since the spring force of the short-stroke moving contact is relatively small, after the short-stroke moving contact contacts the static contact, the reaction force of its spring is not enough to hinder the movement of the long-stroke contact to the other static contact. The timing starts from the time when the short-stroke moving contact contacts the static contact, and ends when the long-stroke moving contact contacts the static contact. This time is the time for the aforementioned limited current to charge the capacitive load. Because of the existence of this charging time, the equivalent capacitance of the capacitive load is no longer zero charge. At the moment when the long-stroke moving contact contacts the static contact, its on-current also becomes the process of reconnecting the capacitive load in the charged state, which greatly reduces the short-circuit impact of the surge current on the relay contacts, thereby extending the service life of the relay.

[0056] The above principle is explained below in conjunction with specific application examples:

[0057] Assume that the time it takes for a power supply with an internal resistance of 0.5 ohms to fully charge a 470UF capacitive load is t = RC = 0.5 × 470 × 10 -6 =0.23ms. When the internal resistance of the surge suppressor connected in series is 2 ohms, the overall equivalent internal resistance of the circuit is 2.5 ohms, and the current for charging the same capacitive load is reduced to 0.2 times of the previous current, and the time for full charging is extended by 5 times to 1.18ms. When the time difference between the closing of the long-stroke moving contact of the arc-extinguishing relay and the short-stroke moving contact is greater than 1.18ms, the time for the power supply to fully charge the 470UF capacitive load is completed by this group of short-stroke moving and static contacts alone with 0.2 times the previous charging current. In this way, the reduction of charging current prolongs the service life of the contacts. When the closing time difference between the long-stroke moving contact of the relay and the short-stroke static contact is less than 1.18ms, assuming the time difference is 0.5ms, the power supply charges the 470UF capacitive load in two steps: within 0.5ms, the short-stroke moving and static contacts are charged with a capacitive load with a current of 0.2 times. After 0.5ms, the equivalent capacitance of the capacitive load is no longer zero charge, and the long-stroke moving contact completes the remaining charging process with a current of 1.0 times, that is, short-circuiting the contacts of the surge current suppression device 5 (that is, the second moving contact 2 and the second static contact 4) to complete the power supply to the load. The charging process is completed in two steps by two groups of contacts with a small current for a long time, which greatly reduces the impact of surge current on the relay contacts, thereby extending the service life of the relay contacts.

[0058] Embodiment three:

[0059] The present invention discloses an arc extinguishing method for an arc extinguishing relay, which adopts the arc extinguishing relay, wherein the arc extinguishing relay comprises: a first moving contact 1, a second moving contact 2, a first static contact 3, a second static contact 4, and an armature capable of pulling the first moving contact 1 and the second moving contact 2 to be attracted or disconnected with the first static contact 3 and the second static contact 4 respectively; the first moving contact 1 and the second moving contact 2 are connected in parallel, the first static contact 3 is connected to the second static contact 4 through a surge current suppression device 5, and when the armature pulls the first moving contact 1 and the second moving contact 2 to be attracted with the first static contact 3 and the second static contact 4 respectively, the time when the first moving contact 1 reaches the first static contact 3 is inconsistent with the time when the second moving contact 2 reaches the second static contact 4.

[0060] As an example, when the armature pulls the first moving contact 1 and the second moving contact 2 to attract the first static contact 3 and the second static contact 4 respectively, the time for the first moving contact 1 to reach the first static contact 3 is less than the time for the second moving contact 2 to reach the second static contact 4;

[0061] Optionally, the time for the first movable contact 1 to reach the first static contact 3 is shorter than the time for the second movable contact 2 to reach the second static contact 4, which can be adjusted by the following method.

[0062] For example, it can be achieved by adjusting the thickness of the moving contact, or by adjusting the thickness of the stationary contact, or by adjusting the position spacing of the moving contact or the stationary contact.

[0063] In the above implementation process, the two moving contacts are pulled by the same moving armature.

[0064] Optionally, the stroke of the first movable contact 1 to the first static contact 3 is shorter than the stroke of the second movable contact 2 to the second static contact 4. The two springs of the first movable contact 1 and the second movable contact 2 have different elasticity, the movable contact spring with a shorter stroke has a smaller elastic force, and the movable contact spring with a larger stroke has a larger elastic force.

[0065] Step S1: after the first moving contact 1 reaches the first static contact 3 and before the second moving contact 2 reaches the second static contact 4, the power supply charges the capacitive load through the surge current suppression device 5;

[0066] Step S2: After the second moving contact 2 reaches the second static contact 4, the surge current suppression device 5 is short-circuited, and the power supply continues to charge the capacitive load.

[0067] The time when the two moving contacts reach the static contact under the traction of the same armature mechanism has a strict sequence due to the different thicknesses or positions of the contacts. Therefore, it can accurately ensure the accurate connection and short-circuit of the surge current suppression device 5 to complete the surge current suppression and load power supply work.

[0068] The present invention reduces the surge impact current by connecting a certain surge current suppression device 5 in series, and completes the preliminary charging of the capacitive load at the same time. After a certain time difference, the surge current suppression device 5 is short-circuited, and the load is powered by the contacts (i.e., the second moving contact 2 and the second static contact 4) of the short-circuited surge current suppression device 5. The charging process is completed in two steps by two groups of contacts with a small current for a long time, which greatly reduces the impact of the surge current on the relay contacts, thereby extending the service life of the relay contacts.

[0069] For those skilled in the art, various other corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all of these changes and deformations should fall within the protection scope of the claims of the present invention.

Claims

1. An arc extinguishing relay, characterized in that: The invention comprises: a first moving contact, a second moving contact, a first static contact and a second static contact; the first moving contact is attracted or disconnected with the first static contact, and the second moving contact is attracted or disconnected with the second static contact; the first moving contact and the second moving contact are connected in parallel, and the first static contact is connected with the second static contact through a surge current suppression device; when the first moving contact and the second moving contact are pulled to attract with the first static contact and the second static contact respectively at the same time, the time when the first moving contact reaches the first static contact is inconsistent with the time when the second moving contact reaches the second static contact, the stroke of the first moving contact to reach the first static contact is shorter than the stroke of the second moving contact to reach the second static contact, the elastic force of the spring sheet used by the first moving contact is different from the elastic force of the spring sheet used by the second moving contact, and the spring sheet of the first moving contact is provided with one or more round holes or fine grooves, which are helpful to reduce the reaction force of the spring sheet of the moving contact with a short stroke, and reduce the resistance for the subsequent movement of the moving contact with a long stroke; Among them, the two moving contacts move toward the static contact under the traction of the same electromagnet, and the moving contact with a shorter stroke first contacts its corresponding static contact, and the inrush current suppression device is first connected to the capacitive load circuit. Under the same voltage environment, its surge current changes from the infinite value of the initial transient short circuit to the limited current under the action of the inrush current suppression device, and charges the capacitive load. Later, another group of contacts with a longer stroke closes, short-circuiting the inrush current suppression device and supplying normal power to the capacitive load.

2. The arc-extinguishing relay according to claim 1, characterized in that: The size of the set area of ​​the reed of the first movable contact is smaller than the size of the set area of ​​the reed of the second movable contact.

3. The arc-extinguishing relay according to claim 1, characterized in that: The thickness of the first moving contact is different from the thickness of the second moving contact.

4. The arc-extinguishing relay according to claim 1, characterized in that: The thickness of the first stationary contact is different from the thickness of the second stationary contact.

5. The arc-extinguishing relay according to claim 1, characterized in that: The position of the first stationary contact relative to the first movable contact is different from the position of the second stationary contact relative to the second movable contact.

6. An arc extinguishing device, characterized in that: It comprises an arc-extinguishing relay as described in any one of claims 1 to 5, a capacitive load and a power supply, wherein the arc-extinguishing relay is connected in series with the capacitive load and the power supply to form a load circuit, wherein a connection point between a first moving contact and a second moving contact of the arc-extinguishing relay is connected to one end of the capacitive load, a first static contact of the arc-extinguishing relay is connected to one end of the power supply, and a connection point where the first static contact of the arc-extinguishing relay is connected to the second static contact via a surge current suppression device is connected to the other end of the power supply.

7. An arc extinguishing method, characterized in that: The arc extinguishing device according to claim 6 comprises: When the armature pulls the first moving contact and the second moving contact to engage with the first static contact and the second static contact respectively, the time for the first moving contact to reach the first static contact is less than the time for the second moving contact to reach the second static contact; After the first moving contact reaches the first stationary contact and before the second moving contact reaches the second stationary contact, the power supply charges the capacitive load through the surge current suppression device; after the second moving contact reaches the second stationary contact, the surge current suppression device is short-circuited and the power supply continues to charge the capacitive load.

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