Electronic contact opening and closing device

Abstract

The utility model discloses an electronic contact switch. A movable contact module, a left group of static contact modules and a right group of static contact modules of the electronic contact opening and closing device are integrally packaged in a shell; a control circuit board of the static contact module comprises a rectifier bridge circuit, a first magnetic reed pipe and a motor driving circuit based on a bidirectional silicon controlled rectifier; the physical position of the first magnetic reed pipe on the control circuit board is close to the edge of one end of the movable contact module; an alternating-current part of the motor driving circuit is connected with an alternating-current power supply, and a bidirectional silicon controlled rectifier is used as an electronic switch on a motor power supply loop; the rectifier bridge circuit takes electricity from an alternating current power supply, and the first magnetic reed pipe is connected in series to a direct current part of the rectifier bridge circuit; a contact (magnet) of the movable contact module is close to the first magnetic reed pipe to conduct the first magnetic reed pipe, and a low-voltage direct-current power source is generated to trigger the bidirectional silicon controlled rectifier to conduct so that the motor can be powered on to operate. According to the invention, the on-off control of the AC driving circuit can be stably and reliably realized, and the overall structure of the shutter is more simplified.

Description

Technical Field

[0001] The present application belongs to the field of railway signal technology, and specifically relates to a switch-operated, static contact, non-contact switch. Background Art

[0002] Switch machines are widely used in the field of rail transportation. There are many manufacturers and models of products, but the internal structure is similar. Take the widely used ZDJ9 AC switch machine as an example. Its internal circuit structure is as follows: Figure 1 As shown, there are two sets of three-position double-throw switches on the left and right, with static contacts 41 to 46 and 31 to 36 on the left and 21 to 26 and 11 to 16 on the right. The solid circle represents the moving contact, which can move left and right to connect or disconnect the upper and lower static contacts. Figure 1 In the circuit, contacts 11-14 and 41-44 connect the b and c windings of the motor and the AC380V power supply. When contacts 11-14 are connected and contacts 41-44 are disconnected, the switch is in the positioned position; when contacts 41-44 are connected and contacts 11-14 are disconnected, the switch is in the reverse position.

[0003] The designs of the left and right sets of static contacts are usually the same, so usually only the structure of the static contact on one side and its coordination structure with the moving contact are discussed.

[0004] The existing technology mainly uses mechanical contacts, such as the solutions provided in patent documents CN201023491Y (A new reinforced static contact group for railway electric switch), CN201354084Y (Redundant defrosting contact group for switch), and CN205469117U (Balanced redundant contact group for switch). The disadvantages of mechanical contacts are:

[0005] (1) Due to non-sealing, moisture and dust may cause the contacts to oxidize and contaminate, increasing the contact resistance;

[0006] (2) Metal fatigue causes contact pressure changes or fracture;

[0007] (3) Improper installation or adjustment results in incorrect contact surface posture of the dynamic / static contacts, asynchronous on-off action of each contact, or inconsistent contact resistance;

[0008] (4) Mechanical wear causes changes in contact resistance and a limited lifespan.

[0009] In recent years, some scholars have proposed the idea of ​​non-contact. For example, patent document CN115360051A proposes a contactless switch and moving contact group for a switch machine, which uses magnetic induction or photoelectric induction to realize the conversion and transmission of switch signals when the moving contact column is driven into or out of the induction tooth mouth on the static contact seat. The magnetic induction scheme mentioned therein is specifically as follows: a specific magnet is fixed on the induction contact of the moving contact. When the moving contact is driven into the induction area of ​​the static contact, the magnetic field in the area changes. At this time, the magnetic induction sensor module embedded in the static contact senses the change in the magnetic field and converts it into an electrical signal and transmits it to the control board module. The control board module processes and makes logical judgments on the transmitted electrical signal and reliably drives the built-in relay or transistor. By connecting and disconnecting the built-in relay or transistor, the corresponding terminal circuit is connected or disconnected.

[0010] However, this solution essentially simply improves the specific connection method between the moving and stationary contacts, replacing the original three-phase (three) mechanical moving contacts with three-phase (three) magnetic induction switches or optical induction switches. While theoretically avoiding the aforementioned shortcomings of mechanical contacts (direct contact), it typically requires separate DC power supplies and control circuits for these three switches, significantly increasing the complexity of the structure. Furthermore, the control circuit is always powered, which consumes the life of the components and may also lead to unstable circuit performance and reduced reliability over time. Summary of the Invention

[0011] The present application provides an electronic contact switch to solve the problems of reduced reliability of existing mechanical contact solutions due to metal fatigue and contact resistance changes, as well as the complex structure of magnetic induction or photoelectric induction dynamic and static contact connection solutions.

[0012] In order to achieve the above objectives, this application provides the following technical solutions:

[0013] An electronic contact switch comprises a movable contact module and two sets of left and right stationary contact modules, wherein the stationary contact modules include a control circuit board. A special feature of the electronic contact switch is that the movable contact module and the two sets of stationary contact modules are integrally encapsulated within a housing. The control circuit board includes a rectifier bridge circuit, a first reed switch, and a motor drive circuit based on a bidirectional thyristor. The first reed switch is physically located on the control circuit board near the edge of one end of the movable contact module.

[0014] The motor drive circuit is divided into an AC part and a DC part, wherein the AC part is connected to an AC power supply and uses a bidirectional thyristor as an electronic switch on the motor power supply circuit; the DC part is a trigger circuit of the bidirectional thyristor;

[0015] The rectifier bridge circuit is divided into an AC part and a DC part, wherein the power supply of the AC part comes from the AC power supply, and the DC part is connected in series with the first reed tube to provide a low-voltage DC power supply to the DC part of the motor drive circuit;

[0016] The contacts of the moving contact module are magnets. When the contacts of the moving contact module swing to one side and into position, the first reed tube on the control circuit board of the proximal static contact module is reliably closed, and the first reed tube on the control circuit board of the distal static contact module is reliably disconnected; the DC part of the rectifier bridge circuit is turned on by the closure of the first reed tube, generating the low-voltage DC power supply, thereby triggering the bidirectional thyristor to turn on so that the motor power supply circuit is connected to the AC power supply.

[0017] Optionally, the series circuit where the DC part of the rectifier bridge circuit is located has one end connected to the positive terminal Vcc of the low-voltage DC power supply and the other end grounded via the first reed tube; a filter circuit is also provided on the side close to the positive terminal Vcc of the low-voltage DC power supply.

[0018] Optionally, the AC power supply is a three-phase power supply, and accordingly, the AC part of the motor drive circuit is divided into a B-phase circuit and a C-phase circuit. One of the static contact pairs of the B-phase circuit and the C-phase circuit is respectively connected to the B end and the C end of the three-phase power supply, and is respectively connected to the two ends of the rectifier bridge of the rectifier bridge circuit, so that the rectification obtains the BC voltage of the three-phase power supply; a step-down circuit unit composed of a capacitor Cb and a resistor Re in parallel is also connected in series between any static contact and the rectifier bridge; one of the static contact pairs of the B-phase circuit and the C-phase circuit is connected to the corresponding other static contact through a bidirectional thyristor.

[0019] Furthermore, the static contact pairs of each phase B circuit and phase C circuit each employ a single bidirectional thyristor (TRIAC) as the switch for that circuit, or two bidirectional thyristors of the same model connected in parallel. Using a parallel thyristor structure can reduce the load current flowing through a single thyristor element and maintain proper contact opening and closing function even if a single thyristor experiences an open-circuit fault, thereby improving circuit reliability and extending service life.

[0020] Further optionally, in the B-phase circuit and the C-phase circuit, a protection circuit consisting of a resistor Rd and a capacitor Ca is connected in parallel at both ends of the bidirectional thyristor.

[0021] Further optionally, the DC part of the motor drive circuit includes the low-voltage DC power supply positive terminal Vcc, a zero-crossing optocoupler and a bidirectional thyristor, the low-voltage DC power supply positive terminal Vcc is connected to the ground via the input side of the zero-crossing optocoupler and the resistor Ra in sequence, and the output side of the zero-crossing optocoupler is connected to the control end of the bidirectional thyristor.

[0022] Optionally, the static contact module further includes a display circuit for generating a signal related to the current position of the switch machine.

[0023] Further optionally, the indicating circuit uses a reed tube to connect the corresponding static contacts, and the on-off state of the reed tube is also associated with the contact swing position of the moving contact module.

[0024] Further optionally, the display circuit is entirely provided on a separate display circuit board, or a portion of the display circuit is provided on a separate display circuit board and another portion of the display circuit is provided on the control circuit board;

[0025] The control circuit board and the display circuit board are arranged in a horizontal direction, and the contact of the movable contact module adopts a bar magnet along the horizontal direction, or adopts a plurality of magnets arranged in the horizontal direction.

[0026] Compared with the prior art, this application has at least the following beneficial effects:

[0027] The non-contact switch proposed in this application has a control circuit board including a rectifier bridge circuit, a first reed switch and a motor drive circuit based on a bidirectional thyristor. The AC part of the motor drive circuit based on the bidirectional thyristor is connected to an AC power supply, and a bidirectional thyristor is used as an electronic switch on the motor power supply circuit; the DC part is a trigger circuit of the bidirectional thyristor; the rectifier bridge circuit draws power from the AC power supply, and the first reed switch is connected in series to the DC part of the rectifier bridge circuit to generate a low-voltage DC power supply. The contact (magnet) of the moving contact module is close to the first reed switch to turn it on, so that the DC part of the rectifier bridge circuit where the first reed switch is located is turned on, generating a low-voltage DC power supply, and then triggering the bidirectional thyristor to turn on so that the motor power supply circuit is connected to the AC power supply, thereby realizing forward / reverse rotation of the motor.

[0028] This application breaks through the traditional idea of ​​a one-to-one correspondence between the number and orientation of moving contacts (contact swing) and static contacts. It uses a reed tube to draw power from the original AC power supply through a rectifier bridge circuit, and triggers the bidirectional thyristor to turn on through the generated DC voltage to achieve the required "contact closure". This solution not only avoids the problem of reduced reliability of mechanical contact solutions due to metal fatigue and contact resistance changes, but also achieves stable and reliable on-off control of the AC drive circuit through a clever power supply method (no need to add an additional DC power supply) combined with a bidirectional thyristor; in addition, this electronic contact switch also simplifies the overall structure of the switch.

[0029] In the present application, when the switch machine is in a non-operating state, the control circuit board is not powered and does not consume electricity, which is beneficial to extending the service life of related components. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] To more intuitively illustrate the prior art and the present application, exemplary drawings are provided below. It should be understood that the specific shapes and structures shown in the drawings should not generally be considered as limiting conditions for implementing the present application; for example, based on the technical concepts disclosed in this application and the exemplary drawings, those skilled in the art are capable of easily making routine adjustments or further optimizations to the addition / reduction / attribution division, specific shapes, positional relationships, connection methods, dimensional ratios, etc. of certain units (components).

[0031] Figure 1 This is a schematic diagram of the internal circuit structure of the ZDJ9 type AC switch machine, which is widely used in this field.

[0032] Figure 2 This is a schematic diagram of the contact working state of an embodiment of the present application.

[0033] Figure 3 This is a schematic diagram of the basic principles of a control circuit board in one embodiment of the present application.

[0034] Figure 4 This is a schematic diagram of the topological structure of the control circuit board in one embodiment of the present application.

[0035] Figure 5 This is a schematic diagram showing the topological structure of a circuit board in one embodiment of the present application.

[0036] Figure 6 This is a schematic diagram of contact connection according to an embodiment of the present application when the turnout is in positioning.

[0037] Figure 7 This is a schematic diagram of contact connection according to an embodiment of the present application when the switch is in the reverse position.

[0038] Figure 2 The tags in are as follows:

[0039] 100-housing;

[0040] 200-moving contact module; 201-swing seat; 202-permanent magnet;

[0041] 300-static contact module; 301-reed switch; 302-circuit board; 303-protective cover; 304-static contact module body; 305-mounting bolt; 306-wire; 307-fixing screw. DETAILED DESCRIPTION

[0042] The present application will be further described below in detail through specific embodiments in conjunction with the accompanying drawings.

[0043] In the description of this application: unless otherwise specified, the meaning of "plurality" is two or more. The terms "first", "second", "third", etc. in this application are intended to distinguish the objects referred to and do not have any special meaning in terms of technical connotation (for example, they should not be understood as emphasizing the importance or order, etc.). Expressions such as "including", "comprising", "having", etc. also mean "not limited to" (certain units, components, materials, steps, etc.).

[0044] The embodiments of the present application relate to railway turnout switching technology, specifically a 380V AC power supply transfer switch inside a switch machine, and can also be applied to other motor control scenarios.

[0045] like Figure 2 As shown, in one embodiment of the present application, an electronic contact switch includes a movable contact module 200 and two sets of left and right stationary contact modules 300, which can be enclosed in a housing 100. The movable contact module includes a swinging seat 201 and a magnet (permanent magnet 202) serving as a contact. The contact can swing between the two sets of stationary contact modules. The reed switch 301 is physically located on the circuit board 302 of the stationary contact module as close as possible to one end edge of the movable contact module 200 so that the reed switch can reliably close when the contacts of the movable contact module approach, thereby achieving switch switching. Each set of stationary contact module bodies 304 are fixed by mounting bolts 305. The rear end lead wire structure of the stationary contact module (such as wire loops, gaskets, etc.) can adopt the relevant structure of existing mechanical contacts. For example, the circuit board of the stationary contact module and its lead wires 306 are fastened to the stationary contact module body by fixing screws 307. The circuit board 302 can be equipped with a protective cover 303.

[0046] like Figure 3 、 Figure 4 As shown, the control circuit board of the static contact module includes a rectifier bridge circuit, a first reed tube Ga and a motor drive circuit based on a bidirectional thyristor; the motor drive circuit is divided into an AC part and a DC part, wherein the AC part is connected to the AC power supply (of the motor) and uses a bidirectional thyristor as an electronic switch on the motor power supply circuit, and the DC part is a trigger circuit of the bidirectional thyristor; the rectifier bridge circuit is divided into an AC part and a DC part, wherein the power supply of the AC part comes from the AC power supply, and the DC part is connected in series with the first reed tube Ga to provide a low-voltage DC power supply to the DC part of the motor drive circuit; the contact of the moving contact module uses a magnet. When the contact of the moving contact module swings to one side and is in place, the proximal static contact module (the group of static contact modules close to the magnet side, such as Figure 2The first reed switch on the control circuit board of the left static contact module (shown) is reliably closed, and the first reed switch on the control circuit board of the remote static contact module (another set of static contact modules) is reliably disconnected; the DC part of the rectifier bridge circuit is turned on by the closure of the first reed switch to generate the low-voltage DC power supply, thereby triggering the bidirectional thyristor to turn on and connect the motor power supply circuit to the AC power supply.

[0047] The series circuit where the DC part of the rectifier bridge circuit is located has one end connected to the positive terminal Vcc of the low-voltage DC power supply and the other end grounded through the first reed tube; a filter circuit (RC parallel circuit) is also provided on the side close to the positive terminal Vcc of the low-voltage DC power supply.

[0048] comparison Figure 1 and Figure 4 In one embodiment of the present application, electronic switches replace the mechanical contacts 11 to 14 and 41 to 44. Specifically, taking a single-sided static contact module as an example: for driving a three-phase motor, the AC part of the motor drive circuit can be divided into a B-phase circuit and a C-phase circuit. One static contact (i.e., contacts 13 and 11) in each static contact pair of the B-phase circuit and the C-phase circuit is respectively connected to the B-end and the C-end of the three-phase power supply, and is also respectively connected to the two ends of the rectifier bridge of the rectifier bridge circuit, so that the rectification obtains the voltage between BC of the three-phase power supply; a step-down circuit unit composed of a capacitor Cb and a resistor Re in parallel is also connected in series between any static contact and the rectifier bridge; one static contact (i.e., contacts 13 and 11) in each static contact pair of the B-phase circuit and the C-phase circuit is connected to the corresponding other static contact (i.e., contacts 14 and 12) via a bidirectional thyristor.

[0049] In the B-phase and C-phase circuits, two bidirectional thyristors of the same model can be connected in parallel to function as an electronic switch. This reduces the load current flowing through a single thyristor component and maintains proper contact opening and closing function even if a single thyristor experiences an open-circuit fault. In short, using a parallel thyristor structure can improve circuit reliability and extend service life.

[0050] In the B-phase circuit and the C-phase circuit, a protection circuit consisting of a resistor Rd and a capacitor Ca is connected in parallel at both ends of the bidirectional thyristor.

[0051] The DC part of the motor drive circuit includes a low-voltage DC power supply positive terminal Vcc, a zero-crossing optocoupler and a bidirectional thyristor. The low-voltage DC power supply positive terminal Vcc is connected to the ground via the input side of the zero-crossing optocoupler and the resistor Ra in sequence, and the output side of the zero-crossing optocoupler is connected to the control end of the bidirectional thyristor.

[0052] Compared with the solution of the aforementioned patent document CN115360051A, this embodiment has the following advantages:

[0053] (1) No external working power supply is required. The 380V AC voltage between the BC terminals of the static contact is used to generate the VCC DC voltage required by the thyristor drive circuit through voltage reduction, rectification and filtering. The circuit is simple and compact.

[0054] (2) Only one magnetic sensor Ga on the control circuit board can realize the synchronous on / off of the B and C phase power supplies. Compared with multi-channel magnetic sensor elements, it can avoid the potential risks caused by the failure of multiple magnetic sensor elements at different times, such as the risk of fault amplification caused by the loss of one phase.

[0055] (3) The power is taken from the B-phase and C-phase terminals of the static contact, which has a simple structure. When the switch machine is in a non-operating state, the control circuit board is not powered and does not consume electricity, which is beneficial to extending the service life of related components.

[0056] The static contact module also includes an indication circuit, primarily used to generate a signal indicating the switch's current position. This indication circuit uses a reed switch connected to the corresponding static contact. The on / off state of the reed switch is also correlated with the swing position of the moving contact module's contacts.

[0057] The display circuit can be entirely arranged on a separate display circuit board, or a portion of the display circuit can be arranged on a separate display circuit board and the other portion of the display circuit can be arranged on the control circuit board; the control circuit board and the display circuit board are arranged in a horizontal direction, so that all the reed switches can be arranged in a line along the horizontal direction as much as possible. Accordingly, the contact of the moving contact module can adopt a bar magnet along the horizontal direction, or a plurality of magnets arranged along the horizontal direction.

[0058] Analysis of the working process of the switch machine:

[0059] When the switch machine starts, AC380V three-phase power is applied to ABC, and AC380V voltage is applied between BC. The magnet swings close to the position of the first reed tube Ga, which closes. The trigger circuit of the bidirectional thyristor operates, generating a trigger signal. The two bidirectional thyristors conduct, and the switch machine motor receives 380V three-phase AC power and begins to operate. During this process, phases B and C of the three-phase AC380V power supply are sent to contacts 11, 13 or 41, 43, thereby energizing motor windings b and c. Phase a of the motor is connected to phase A of the power supply without passing through the contacts. The DC power required for the trigger control circuit of the bidirectional thyristor is taken from the AC380V voltage between contacts 11-13 and contacts 41-43. Specifically:

[0060] When the switch machine is started, AC380V is applied between 11-13 or 41-43. The magnet activates the first reed resistor Ga, which then steps down the voltage through Cb. A sinusoidal voltage is applied to the rectifier bridge, filtered by RC, generating the DC operating voltage Vcc. Two zero-crossing optocouplers operate, and two bidirectional thyristors K1 and K2 conduct. Three-phase AC380V is applied to the switch machine motor, causing the motor to rotate. Once the three-phase AC380V is disconnected, Ga turns off, and the circuit stops operating. Rd, Ca, R, and C serve as protection components.

[0061] like Figure 4 、 Figure 5 As shown, the remaining contact pairs (45, 46), (31, 32), (33, 34), (35, 36), (21, 22), (23, 24), (25, 26), and (15, 16) are all related to the display circuit. Since the voltage and current of the display circuit are not high, a reed switch can also be used to implement it.

[0062] like Figure 6 、 Figure 7 As shown, the motor-related circuits and static contacts are marked with colored lines. Only contacts 11-14 and 41-44 are related to motor operation. The magnetic sensor that controls motor operation is a single reed switch (the first reed switch Ga). The other contacts 31-36, 45-46, 21, 26, 15, and 16 are only related to the indication circuit and have no effect on motor operation. The indication circuit generates a signal indicating the current position of the switch and also checks the normal operation of the motor windings.

[0063] Two sets of circuit boards, left and right, are installed in one housing. Each set of circuit boards is divided into control circuit boards (such as Figure 4 As shown) and the circuit board (as shown Figure 5 As shown, the core of each control circuit board is a reed diode Ga and two bidirectional thyristors. The bidirectional thyristors are driven by zero-crossing optocouplers. Their DC operating power comes from AC380V, which is stepped down by capacitors and filtered by full-bridge rectification. The activation of the DC operating power is jointly controlled by the switch motor contact magnet and the reed diode Ga. The circuit principles and component parameters of the left and right control circuit boards are identical. The wiring is adjusted accordingly, so that one control circuit board is responsible for driving the motor forward and the other for driving the motor reverse. The wiring and wiring adjustments in this regard are conventional technical means in the field and will not be elaborated here.

[0064] Figure 4 The control circuit board of the embodiment shown also integrates a portion of the display circuit ( Figure 4(left side of the image), G is the reed resistor, and R and C serve as protection components. It should be understood that this portion of the display circuit is relatively independent of the main circuit of the control circuit board (rectifier bridge circuit, first reed resistor, and triac-based motor drive circuit). Therefore, in actual products, this portion of the display circuit may not be located on the control circuit board.

[0065] To facilitate compact packaging, the four circuit boards can be of the same shape and size. The circuit board base has two mounting holes and six wire-pressing screw holes, which correspond to the six wiring holes on the circuit board. The installation sequence is as follows: First, secure the base to the switch machine mounting base with two M6 bolts. Then, insert the wire loops into the screws with six M5 screws. Finally, insert the screws through the circuit board wiring holes and screw them into the corresponding screw holes on the base, securing the circuit board and external wiring.

[0066] The permanent magnets on the swinging components of the switch's mechanical contacts should ensure that when they swing to the left or right dead center, the reed switch contacts on the adjacent circuit board are reliably closed, and the reed switch contacts on the other circuit board are reliably disconnected. This adaptive design is a conventional technical means in the field and will not be elaborated here.

[0067] A protective cover can be provided on the outside of the circuit board of the single-sided static contact module. This cover physically isolates the "contact elements" of the static contact module from the contacts of the moving contact module. The contacts of the moving contact module do not even need to come into contact with the cover, as long as the contacts of the moving contact module are sufficiently close to the first reed switch on the control circuit board within the cover to achieve conduction. The protective cover of the single-sided static contact module can have any shape on the side facing the moving contact, and does not need to have special teeth to mate with the contacts of the moving contact as in the solution of patent document CN115360051A. Instead, it can be designed as a vertical plane, an oblique plane, or other surfaces. Furthermore, considering that the moving contact module and two sets of static contact modules are integrally enclosed in a single housing, the protective cover on the outside of the single-sided static contact module can theoretically be omitted.

[0068] The electronic contact switch provided in this embodiment breaks through the traditional idea of ​​a one-to-one correspondence between the number and orientation of moving contacts (contact swing) and static contacts. It uses a reed tube to draw power from the original AC power supply through a rectifier bridge circuit, and uses the generated DC voltage to trigger the bidirectional thyristor to turn on, thereby achieving the required "contact closure". This solution not only avoids the problem of reduced reliability caused by metal fatigue and contact resistance changes in mechanical contact solutions, but also achieves stable and reliable on-off control of the AC drive circuit through a clever power supply method (no additional DC power supply is required) combined with a bidirectional thyristor. In addition, this electronic contact switch also simplifies the overall structure of the switch.

[0069] The technical features of the above embodiments can be combined arbitrarily (as long as there is no contradiction in the combination of these technical features). In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described; these embodiments that are not explicitly written should also be considered to be within the scope of this specification.

Claims

1. An electronic contact switch, comprising a movable contact module and two sets of left and right static contact modules, wherein the static contact modules include a control circuit board; characterized in that: The movable contact module and the left and right sets of stationary contact modules are integrally encapsulated in a housing; the control circuit board includes a rectifier bridge circuit, a first reed switch, and a motor drive circuit based on a bidirectional thyristor; the first reed switch is physically located on the control circuit board near the edge of one end of the movable contact module; The motor drive circuit is divided into an AC part and a DC part, wherein the AC part is connected to an AC power supply and uses a bidirectional thyristor as an electronic switch on the motor power supply circuit; the DC part is a trigger circuit of the bidirectional thyristor; The rectifier bridge circuit is divided into an AC part and a DC part, wherein the power supply of the AC part comes from the AC power supply, and the DC part is connected in series with the first reed tube to provide a low-voltage DC power supply to the DC part of the motor drive circuit; The contacts of the moving contact module are magnets. When the contacts of the moving contact module swing to one side and into position, the first reed tube on the control circuit board of the proximal static contact module is reliably closed, and the first reed tube on the control circuit board of the distal static contact module is reliably disconnected; the DC part of the rectifier bridge circuit is turned on by the closure of the first reed tube, generating the low-voltage DC power supply, thereby triggering the bidirectional thyristor to turn on so that the motor power supply circuit is connected to the AC power supply.

2. The electronic contact switch according to claim 1, characterized in that: The series circuit where the DC part of the rectifier bridge circuit is located has one end connected to the positive terminal Vcc of the low-voltage DC power supply and the other end grounded through the first reed tube; a filter circuit is also provided on the side close to the positive terminal Vcc of the low-voltage DC power supply.

3. The electronic contact switch according to claim 2, characterized in that: The AC power supply is a three-phase power supply. Accordingly, the AC part of the motor drive circuit is divided into a B-phase circuit and a C-phase circuit. One of the static contact pairs of the B-phase circuit and the C-phase circuit is respectively connected to the B end and the C end of the three-phase power supply, and is also respectively connected to the two ends of the rectifier bridge of the rectifier bridge circuit, so that the rectification obtains the BC voltage of the three-phase power supply; a step-down circuit unit composed of a capacitor Cb and a resistor Re in parallel is also connected in series between any static contact and the rectifier bridge; one of the static contact pairs of the B-phase circuit and the C-phase circuit is connected to the corresponding other static contact via a bidirectional thyristor.

4. The electronic contact switch according to claim 3, characterized in that: In the B-phase circuit and the C-phase circuit, a protection circuit consisting of a resistor Rd and a capacitor Ca is connected in parallel at both ends of the bidirectional thyristor.

5. The electronic contact switch according to claim 3, characterized in that: The DC part of the motor drive circuit includes the positive terminal Vcc of the low-voltage DC power supply, a zero-crossing optocoupler and a bidirectional thyristor. The positive terminal Vcc of the low-voltage DC power supply is connected to the input side of the zero-crossing optocoupler and the resistor Ra in sequence, and the output side of the zero-crossing optocoupler is connected to the control end of the bidirectional thyristor.

6. The electronic contact switch according to claim 1, characterized in that: The static contact module further comprises a display circuit for generating a signal related to the current position of the switch machine.

7. The electronic contact switch according to claim 6, characterized in that: The indicating circuit uses a reed tube to connect the corresponding static contacts, and the on-off state of the reed tube is also associated with the contact swing position of the moving contact module.

8. The electronic contact switch according to claim 6, characterized in that: The display circuit is entirely provided on a separate display circuit board, or a portion of the display circuit is provided on a separate display circuit board and another portion of the display circuit is provided on the control circuit board; The control circuit board and the display circuit board are arranged in a horizontal direction, and the contact of the movable contact module adopts a bar magnet along the horizontal direction, or adopts a plurality of magnets arranged in the horizontal direction.

9. The electronic contact switch according to claim 3, characterized in that: The static contact pairs of each of the B-phase circuit and the C-phase circuit use a bidirectional thyristor as the switch of the circuit, or use two bidirectional thyristors of the same type connected in parallel as the switch of the circuit.

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