Motor control circuit and switch

Abstract

The utility model relates to automatic transfer switch control technical field discloses a kind of motor control circuit and switch, and motor control circuit includes: power input module, first relay, second relay, signal control unit, positive rotation contact terminal, reverse rotation contact terminal, positive rotation position detection switch and reverse rotation position detection switch, using pure analog circuit design, realize automatic transfer switch remote control, solve the defect that traditional single-chip microcontroller programming control realizes remote control circuit design complex cost high.Adopting double relay control motor's positive rotation, reverse positive rotation realizes the mutual switching of the frequently-used position of automatic transfer switch, standby position, circuit design is simple, and reliability is high.

Description

Technical Field

[0001] This utility model relates to the field of automatic transfer switch control technology, specifically to a motor control circuit and switch. Background Technology

[0002] Motor forward and reverse rotation control is a crucial component for the core function of automatic transfer switches, and its control performance directly determines the power switching efficiency and stability of the switch. Currently, the industry commonly uses microcontroller-based programming control for motor forward and reverse rotation, but this approach has significant technical limitations in practical applications and struggles to meet specific scenario requirements. From a circuit design perspective, while this solution simplifies the logic control process through programming, it requires additional independent power supply modules, driver modules, and signal detection modules. This not only fails to fundamentally reduce the overall circuit complexity but also further increases the redundancy of the hardware architecture due to the added components. In terms of scenario adaptability, it has poor compatibility with various application scenarios. Due to the high coupling between hardware and program, for simple control scenarios with low cost and small size, it is often necessary to readjust the program logic or modify the hardware layout, resulting in high adaptation costs and insufficient flexibility. From an operation and maintenance perspective, because the circuit contains a large number of components and complex wiring nodes, subsequent debugging and calibration require professional personnel to conduct dual checks on both the program and hardware. Fault location during maintenance is difficult, significantly increasing operation and maintenance costs and time.

[0003] In summary, current automatic transfer switch motor forward / reverse control circuits generally suffer from core problems such as complex structure, high cost, and insufficient reliability, which can no longer meet the industry's development needs for simplified, low-cost, and highly reliable control circuits. Therefore, there is an urgent need to develop a simplified control circuit with fewer components, simpler wiring, and a balance between cost control and operational reliability, in order to effectively meet the core demands of automatic transfer switches for efficient and low-cost motor forward / reverse control. Utility Model Content

[0004] This invention provides a motor control circuit and switch to solve the problems of complex structure, high cost, and insufficient reliability of current automatic transfer switch motor forward and reverse control circuits.

[0005] In a first aspect, this utility model provides a motor control circuit, which includes: a power input module, a first relay, a second relay, a signal control unit, forward rotation contact terminals, reverse rotation contact terminals, a forward rotation position detection switch, and a reverse rotation position detection switch, wherein... The forward and reverse power input terminals of the power input module are both used to connect to AC voltage, providing power for the motor's forward and reverse rotation, respectively. The coil of the first relay is electrically connected to the forward power input terminal, the first moving contact of the first relay is connected to the main power output terminal of the power input module, and the first moving contact selectively connects to the positive terminal of the forward power input terminal or the positive terminal of the reverse power input terminal. The second moving contact of the first relay is connected to the negative terminal of the motor of the power input module, and the second moving contact selectively connects to the negative terminal of the forward power input terminal or the negative terminal of the reverse power input terminal. The coil of the second relay is connected to the system power supply. The first moving contact of the second relay is connected to the forward rotation terminal of the forward rotation contact terminal. The normally closed contact corresponding to the first moving contact is connected to the forward rotation pin of the motor. The second moving contact of the second relay is connected to the reverse rotation terminal of the reverse rotation contact terminal. The normally closed contact corresponding to the second moving contact is connected to the reverse rotation pin of the motor. When the motor control circuit is in automatic control mode, the automatic control signal terminal of the signal control unit is short-circuited with the main power output terminal of the power input module, and the automatic control signal terminal selectively connects the forward control signal terminal of the forward rotation contact terminal or the reverse control signal terminal of the reverse rotation contact terminal. The forward control signal terminal of the forward rotation contact terminal is short-circuited to the forward wiring terminal of the forward rotation contact terminal through a forward position detection switch, and the reverse control signal terminal of the reverse rotation contact terminal is short-circuited to the reverse wiring terminal of the reverse rotation contact terminal through a reverse position detection switch.

[0006] This utility model provides a motor control circuit that employs a pure analog circuit design to achieve remote control of an automatic transfer switch. This overcomes the drawbacks of traditional microcontroller-based remote control circuits, which are complex and costly. It uses dual relays to control the motor's forward and reverse rotation, enabling the automatic transfer switch to switch between its active and standby positions. The circuit design is simple and highly reliable.

[0007] In one optional implementation, the main power output terminal of the power input module is short-circuited with the forward control signal terminal of the signal control unit. When it is necessary to manually control the motor to reverse, the main power output terminal of the power input module is short-circuited with the reverse control signal terminal of the signal control unit.

[0008] In one optional implementation, both the forward position detection switch and the reverse position detection switch are microswitches.

[0009] In one optional implementation, the moving contact of the forward position detection switch is connected to the forward terminal, and the normally closed contact of the forward position detection switch is connected to the forward control signal terminal.

[0010] In one optional implementation, the moving contact of the reverse position detection switch is connected to the reverse wiring terminal, and the normally closed contact of the reverse position detection switch is connected to the reverse control signal terminal.

[0011] In one optional embodiment, the motor control circuit further includes a motor manual / automatic selection terminal, which is connected to the negative terminal of the motor. When the motor control circuit is in automatic control mode, the motor manual / automatic selection terminal is short-circuited.

[0012] Secondly, this utility model provides a switch, including the motor control circuit of the first aspect or any corresponding embodiment described above.

[0013] This invention provides a switch that integrates the aforementioned simplified motor control circuit. It eliminates the need for a microcontroller and additional power / drive modules, relying solely on pure analog circuitry for control. This reduces the number of components, resulting in a smaller overall size and lower cost. By replacing microcontroller program control with mechanical microswitch limit switches and relay hardware linkage, it avoids switching failures caused by electromagnetic interference and voltage fluctuations, ensuring reliable switching even in scenarios such as power outages and unstable voltage. Attached Figure Description

[0014] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of a motor control circuit according to an embodiment of the present utility model; Figure 2 This is a schematic diagram of the external power input interface according to an embodiment of the present utility model; Figure 3 This is a schematic diagram of the power supply and motor forward / reverse rotation selection circuit according to an embodiment of the present utility model; Figure 4 This is a schematic diagram of a micro-switch circuit for connecting an external control motor to start and stop, according to an embodiment of the present invention. Figure 5 This is a schematic diagram of the automatic selection of motor and forward / reverse control circuit of permanent magnet synchronous motor according to an embodiment of the present utility model. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0017] It is understood that before using the technical solutions disclosed in the various embodiments of this utility model, users should be informed of the types, scope of use, and usage scenarios of the personal information involved in this utility model in an appropriate manner in accordance with relevant laws and regulations, and user authorization should be obtained.

[0018] This utility model provides a motor control circuit to solve the problems of complex structure, high cost, and insufficient reliability of current automatic transfer switch motor forward and reverse control circuits. The motor control circuit includes: a power input module J5, a first relay K1, a second relay K2, a signal control unit J8, a forward rotation contact terminal J1, a reverse rotation contact terminal J2, a forward rotation position detection switch S3, and a reverse rotation position detection switch S4. Their connection relationships are described below. Figure 1 .

[0019] For details, see Figure 2 The forward power input terminals NA and NN and the reverse power input terminals RA and RN of the power input module J5 are all used to connect to 220V AC voltage to provide power for the forward and reverse rotation of the motor, respectively.

[0020] See Figure 3The coil of the first relay K1 is electrically connected to the forward power input terminals NA and NN. The first moving contact of the first relay K1 is connected to the main power output terminal PO_A of the power input module J5. The first moving contact selectively connects to the positive terminal NA of the forward power input terminal or the positive terminal RA of the reverse power input terminal. The second moving contact of the first relay K1 is connected to the negative terminal DJN of the motor of the power input module J5. The second moving contact selectively connects to the negative terminal NN of the forward power input terminal or the negative terminal RN of the reverse power input terminal. Specifically, the first relay K1 is linked with the forward power input terminals NA and NN to automatically switch the power supply circuit of the motor according to the power input status. When a 220V AC voltage is input to the forward power input terminals NA and NN, the first relay K1 is triggered by the voltage and energizes. At this time, the main power output terminal PO_A selects NA as the positive terminal and the motor negative terminal DJN selects NN as the negative terminal. When there is no voltage input at the forward power input terminals NA and NN, and 220V AC voltage is input at the reverse power input terminals RA and RN, the first relay K1 returns to its normally closed state and switches to the reverse power supply circuit. The main power output terminal PO_A selects RA as the positive terminal and the motor negative terminal DJN selects RN as the negative terminal.

[0021] See Figure 2 and Figure 4 When the motor control circuit is in automatic control mode, the automatic control signal terminal ZD of the signal control unit J8 is shorted to the main power output terminal PO_A of the power input module J5. The automatic control signal terminal ZD selectively connects to the forward control signal terminal DL of the forward contact terminal J1 or the reverse control signal terminal DL1 of the reverse contact terminal J2. Specifically, the automatic control signal terminal ZD needs to be shorted to the main power output terminal PO_A to activate the automatic control function. The automatic control signal terminal ZD can be connected according to the power input status. Figure 3 The forward control signal terminal DL or the reverse control signal terminal DL1 is used. When the forward power input terminals NA and NN are input with 220V AC voltage, the automatic control signal terminal ZD and... Figure 3 The forward control signal terminal DL is connected. When there is no voltage input at the forward power input terminals NA and NN, and a 220V AC voltage is input at the reverse power input terminals RA and RN, the automatic control signal terminal ZD connects to... Figure 3 The inversion control signal terminal DL1 is turned on.

[0022] See Figure 3 and 4The coil of the second relay K2 is connected to the system power supply FS and DJN. The first moving contact of the second relay K2 is connected to the forward rotation terminal NHDJZ of the forward rotation contact terminal J1. The normally closed contact corresponding to the first moving contact is connected to the motor forward rotation pin DJZZ. The second moving contact of the second relay K2 is connected to the reverse rotation terminal RHDJF of the reverse rotation contact terminal J2. The normally closed contact corresponding to the second moving contact is connected to the motor reverse rotation pin DJFZ. The forward rotation control signal terminal DL of the forward rotation contact terminal J1 is shorted to the forward rotation terminal NHDJZ of the forward rotation contact terminal J1 through the forward rotation position detection switch S3. The reverse rotation control signal terminal DL1 of the reverse rotation contact terminal J2 is shorted to the reverse rotation terminal RHDJF of the reverse rotation contact terminal J2 through the reverse rotation position detection switch S4.

[0023] Specifically, when a 220V AC voltage is input to the forward power input terminals NA and NN, the automatic control signal terminal ZD is connected to the forward control signal terminal DL. The automatic control signal terminal ZD is also short-circuited to the main power output terminal PO_A. Simultaneously, pins 1 and 3 of the forward position detection switch S3 are normally closed, causing pins 1 and 3 of the forward contact terminal J1 to short-circuit. The forward terminal NHDJZ receives voltage through the forward contact terminal J1 and transmits it to the motor's forward pin DJZZ. Since both the motor's DJZZ (positive) and DJN (negative) pins have voltage, the permanent magnet synchronous motor begins to rotate forward. When the motor rotates to the normal position of the automatic transfer switch, the mechanical structure triggers the normally open contact of the forward position detection switch S3 to close, causing pins 1 and 3 of the forward position detection switch S3 to open. Pins 1 and 3 of the forward contact terminal J1 simultaneously open, the forward control signal terminal DL loses power, the motor's forward pin DJZZ has no voltage, and the motor stops rotating forward.

[0024] When there is no voltage input at the forward power input terminals NA and NN, and a 220V AC voltage is input at the reverse power input terminals RA and RN, the automatic control signal terminal ZD is connected to the reverse control signal terminal DL1. The automatic control signal terminal ZD is also short-circuited to the main power output terminal PO_A. Simultaneously, pins 1 and 3 of the reverse position detection switch S4 are normally closed, causing pins 1 and 3 of the reverse contact terminal J2 to short-circuit. The reverse terminal RHDJF receives voltage through J2 and transmits it to the motor reverse pin DJFZ. Since both the DJFZ (positive) and DJN (negative) pins of the motor have voltage, the permanent magnet synchronous motor begins to reverse. When the motor reverses to the standby position of the automatic transfer switch, the mechanical structure triggers the normally open contact of the reverse position detection switch S4 to close, causing pins 1 and 3 of the reverse position detection switch S4 to open. Pins 1 and 3 of the reverse contact terminal J2 simultaneously open, de-energizing the reverse control signal terminal DL1. With no voltage at the motor reverse pin DJFZ, the motor stops reversing.

[0025] Further, see Figure 5The motor control circuit also includes: motor manual / automatic selection terminal J10, which is connected to the negative terminal DJN of the motor. When the motor control circuit is in automatic control mode, the motor manual / automatic selection terminal J10 is short-circuited.

[0026] Specifically, the operation of the motor requires a complete power-on circuit between the positive / reverse pin and the negative terminal. The connection between J10 and DJN essentially controls whether the motor's negative terminal circuit can be connected to the power system in automatic mode through its own state (short-circuited / open). When J10 is short-circuited, the motor's negative terminal DJN can be connected to the negative terminal of the power supply in automatic mode (NN of the forward power supply or RN of the reverse power supply) through J10, providing the necessary negative terminal circuit for the motor's operation during automatic control. When J10 is open, the path between the motor's negative terminal DJN and the negative terminal of the power supply in automatic mode is cut off, and the complete circuit required for automatic control cannot be formed. At this time, the circuit can only drive the motor through manual control.

[0027] Therefore, the automatic mode requires two prerequisites: first, the motor manual automatic selection terminal J10 must be shorted; second, the automatic control signal terminal ZD must be shorted to the main power output terminal PO_A.

[0028] Motor forward rotation process: When 220V AC voltage is input to the forward rotation power input terminals NA and NN, the first relay K1 is triggered and energized. At this time, the main power output terminal PO_A selects NA as the positive terminal and the motor negative terminal DJN selects NN as the negative terminal. The automatic control signal terminal ZD is connected to the forward rotation control signal terminal DL. At the same time, pins 1 and 3 of the forward rotation position detection switch S3 are normally closed, causing pins 1 and 3 of the forward rotation contact terminal J1 to be short-circuited. The forward rotation control signal terminal DL obtains voltage through the forward rotation contact terminal J1 and transmits it to the motor forward rotation pin DJZZ. Since there is voltage on both the motor's DJZZ pin (positive) and DJN pin (negative), the permanent magnet synchronous motor starts to rotate forward. When the motor rotates to the normal position of the automatic transfer switch, the mechanical structure triggers the normally open contact of the forward rotation position detection switch S3 to close, pins 1 and 3 of the forward rotation position detection switch S3 to open, and pins 1 and 3 of the forward rotation contact terminal J1 to open simultaneously. The forward rotation control signal terminal DL... Power failure, no voltage at DJZZ pin, motor stops rotating.

[0029] Motor Reverse Process: When there is no voltage input at the forward power input terminals NA and NN, and 220V AC voltage is input at the reverse power input terminals RA and RN, the first relay K1 returns to its normally closed state. The main power output terminal PO_A selects RA as the positive terminal, and the motor negative terminal DJN selects RN as the negative terminal. The automatic control signal terminal ZD is connected to the reverse control signal terminal DL1. At the same time, pins 1 and 3 of the reverse position detection switch S4 are normally closed, causing pins 1 and 3 of the reverse contact terminal J2 to be shorted. The reverse control signal terminal DL1 obtains voltage through J2 and transmits it to the motor reverse pin DJFZ. Since there is voltage at both the DJFZ pin (positive) and the DJN pin (negative) of the motor, the permanent magnet synchronous motor begins to reverse. When the motor reverses to the standby position of the automatic transfer switch, the mechanical structure triggers the normally open contact of the reverse position detection switch S4 to close, pins 1 and 3 of S4 to open, and pins 1 and 3 of the reverse contact terminal J2 to open simultaneously. The reverse control signal terminal DL1 is de-energized, and DJFZ... When there is no voltage at the foot, the motor stops and reverses.

[0030] This utility model provides a motor control circuit that employs a pure analog circuit design to achieve remote control of an automatic transfer switch. This overcomes the drawbacks of traditional microcontroller-based remote control circuits, which are complex and costly. It uses dual relays to control the motor's forward and reverse rotation, enabling the automatic transfer switch to switch between its active and standby positions. The circuit design is simple and highly reliable.

[0031] In one optional implementation, when the motor needs to be manually controlled to rotate forward, the main power output terminal PO_A of the power input module J5 is shorted to the forward control signal terminal DL of the signal control unit J8; when the motor needs to be manually controlled to rotate in reverse, the main power output terminal PO_A of the power input module J5 is shorted to the reverse control signal terminal DL1 of the signal control unit J8.

[0032] Specifically, in manual mode, there is no need to rely on the automatic switching of the second relay K2. The connection between the signal terminal and the main power output terminal PO_A is directly controlled by the signal control unit J8. During manual forward rotation, the forward rotation control signal terminal DL is shorted to the main power output terminal PO_A through the signal control unit J8. The forward rotation position detection switch S3 drives the shorting of pins 1 and 3 of the forward rotation contact terminal J1. The forward rotation control signal terminal DL is energized and supplies power to the motor forward rotation pin DJZZ. The motor rotates forward until it reaches the designated position. Then, the normally open contact of the forward rotation position detection switch S3 closes, the forward rotation contact terminal J1 opens, the forward rotation control signal terminal DL is de-energized, and the motor stops.

[0033] When manually reversing, disconnect the short circuit between the forward control signal terminal DL and the main power output terminal PO_A. Short the reverse control signal terminal DL1 and the main power output terminal PO_A through the signal control unit J8. The reverse position detection switch S4 drives the short circuit between pins 1 and 3 of the reverse contact terminal J2. The reverse control signal terminal DL1 is energized and supplies power to the motor reverse pin DJFZ, causing the motor to reverse. Until the motor reaches the specified position, the normally open contact of the reverse position detection switch S4 closes, the reverse contact terminal J2 opens, the reverse control signal terminal DL1 is de-energized, and the motor stops.

[0034] In one alternative implementation, see [link to implementation details]. Figure 4 Both the forward position detection switch S3 and the reverse position detection switch S4 are microswitches.

[0035] Specifically, the moving contact of the forward position detection switch S3 is connected to the forward terminal NHDJZ, and the normally closed contact of the forward position detection switch S3 is connected to the forward control signal terminal DL. The moving contact of the reverse position detection switch S4 is connected to the reverse terminal RHDJF, and the normally closed contact of the reverse position detection switch S4 is connected to the reverse control signal terminal DL1.

[0036] Specifically, when the forward position detection switch S3 is not triggered, the moving contact and normally closed contact remain connected. At this time, the voltage of the forward position terminal NHDJZ is transmitted to the forward control signal terminal DL through the moving and normally closed contacts of S3. The forward control signal terminal DL then supplies power to the motor forward pin DJZZ through the forward contact terminal J1, driving the motor to rotate continuously forward. When the motor reaches the designated position, the mechanical structure triggers the moving contact, and the moving contact and normally closed contact of S3 disconnect. At this time, the path between the forward position terminal NHDJZ and the forward control signal terminal DL is cut off, DL is de-energized, the motor forward pin DJZZ is not powered, and the motor stops rotating forward, achieving the control of stopping when the position is reached.

[0037] When the reverse position detection switch S4 is not triggered, the moving contact and the normally closed contact are connected. The voltage at the reverse terminal RHDJF is transmitted to the reverse control signal terminal DL1 through the moving and normally closed contacts of S4. DL1 then supplies power to the motor reverse pin DJFZ through the reverse contact terminal J2, driving the motor to continuously reverse. When the motor reverses to the designated position, the mechanical structure triggers S4, the moving contact and the normally closed contact disconnect, the path between the reverse terminal RHDJF and the reverse control signal terminal DL1 is cut off, DL1 is de-energized, the motor reverse pin DJFZ is de-energized, and the motor stops reversing.

[0038] This invention provides a switch, including the motor control circuit described in the above embodiments.

[0039] Specifically, the switch is an automatic transfer switch used to achieve power switching, such as a dual power transfer switch. It uses the motor control circuit of the above-described embodiment as the core control unit. Through the automatic / manual mode switching, precise control of motor forward and reverse rotation, and stop protection at the designated position of the motor control circuit, the mechanical transmission mechanism inside the switch is driven to operate, and finally realizes the automatic transfer switch to switch between the normal position and the standby position to ensure continuous power supply to the load equipment.

[0040] Furthermore, the aforementioned switch padlock structure can be used not only in dual-power transfer switches but also in control and protection switches, because this type of switch requires padlocking to prevent circuit faults and product damage caused by misoperation.

[0041] This invention provides a switch that integrates the aforementioned simplified motor control circuit. It eliminates the need for a microcontroller and additional power / drive modules, relying solely on pure analog circuitry for control. This reduces the number of components, resulting in a smaller overall size and lower cost. By replacing microcontroller program control with mechanical microswitch limit switches and relay hardware linkage, it avoids switching failures caused by electromagnetic interference and voltage fluctuations, ensuring reliable switching even in scenarios such as power outages and unstable voltage.

[0042] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A motor control circuit, characterized in that, The motor control circuit includes: a power input module (J5), a first relay (K1), a second relay (K2), a signal control unit (J8), a forward rotation contact terminal (J1), a reverse rotation contact terminal (J2), a forward rotation position detection switch (S3), and a reverse rotation position detection switch (S4), wherein... The forward and reverse power input terminals of the power input module (J5) are both used to connect to AC voltage, providing power for the motor's forward and reverse rotation respectively; The coil of the first relay (K1) is electrically connected to the forward power input terminal. The first moving contact of the first relay (K1) is connected to the main power output terminal (PO_A) of the power input module (J5). The first moving contact selectively connects to the positive terminal of the forward power input terminal or the positive terminal of the reverse power input terminal. The second moving contact of the first relay (K1) is connected to the negative terminal (DJN) of the motor of the power input module (J5). The second moving contact selectively connects to the negative terminal of the forward power input terminal or the negative terminal of the reverse power input terminal. The coil of the second relay (K2) is connected to the system power supply. The first moving contact of the second relay (K2) is connected to the forward rotation terminal (NHDJZ) of the forward rotation contact terminal (J1). The normally closed contact corresponding to the first moving contact is connected to the forward rotation pin (DJZZ) of the motor. The second moving contact of the second relay (K2) is connected to the reverse rotation terminal (RHDJF) of the reverse rotation contact terminal (J2). The normally closed contact corresponding to the second moving contact is connected to the reverse rotation pin (DJFZ) of the motor. When the motor control circuit is in automatic control mode, the automatic control signal terminal (ZD) of the signal control unit (J8) is short-circuited with the main power output terminal (PO_A) of the power input module (J5), and the automatic control signal terminal (ZD) selectively connects the forward control signal terminal (DL) of the forward contact terminal (J1) or the reverse control signal terminal (DL1) of the reverse contact terminal (J2). The forward control signal terminal (DL) of the forward contact terminal (J1) is shorted to the forward wiring terminal (NHDJZ) of the forward contact terminal (J1) through the forward position detection switch (S3), and the reverse control signal terminal (DL1) of the reverse contact terminal (J2) is shorted to the reverse wiring terminal (RHDJF) of the reverse contact terminal (J2) through the reverse position detection switch (S4).

2. The motor control circuit according to claim 1, characterized in that, When the motor needs to be manually controlled to rotate forward, the main power output terminal (PO_A) of the power input module (J5) is short-circuited with the forward control signal terminal (DL) of the signal control unit (J8). When the motor needs to be manually controlled to rotate in reverse, the main power output terminal (PO_A) of the power input module (J5) is short-circuited with the reverse control signal terminal (DL1) of the signal control unit (J8).

3. The motor control circuit according to claim 1, characterized in that, Both the forward position detection switch (S3) and the reverse position detection switch (S4) are micro switches.

4. The motor control circuit according to claim 3, characterized in that, The moving contact of the forward position detection switch (S3) is connected to the forward terminal (NHDJZ), and the normally closed contact of the forward position detection switch (S3) is connected to the forward control signal terminal (DL).

5. The motor control circuit according to claim 3, characterized in that, The moving contact of the reverse position detection switch (S4) is connected to the reverse terminal (RHDJF), and the normally closed contact of the reverse position detection switch (S4) is connected to the reverse control signal terminal (DL1).

6. The motor control circuit according to claim 1, characterized in that, The motor control circuit also includes a motor manual / automatic selection terminal (J10), which is connected to the negative terminal (DJN) of the motor. When the motor control circuit is in automatic control mode, the motor manual / automatic selection terminal (J10) is short-circuited.

7. A switch, characterized in that, Includes the motor control circuit as described in any one of claims 1-6.

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