Overhead line system interconnection load switch capable of balancing potential and use method of overhead line system interconnection load switch

Abstract

The invention relates to a potential-balanced contact network interconnection load switch and a use method thereof, which are used for solving the problem that equipment is discharged and burnt due to voltage difference between two sides when an isolation switch is adopted by the existing contact network interconnection switch. Comprising a load switch, a transmission connecting rod and a control box, the load switch comprises a switch base, a wiring terminal A, a wiring terminal B and a conductive piece, the wiring terminal A and the wiring terminal B are both relatively and fixedly connected with the switch base, the switch base is further provided with a sensor A for detecting the voltage at the wiring terminal A and a sensor B for detecting the voltage at the wiring terminal B, and the conductive piece is connected with the transmission connecting rod. A motor and a speed reducer are arranged in the control box, a transmission shaft is arranged at the output end of the motor and the output end of the speed reducer, the transmission shaft is fixedly connected with the lower end of a transmission connecting rod through a connecting piece, and the upper end of the transmission connecting rod is connected with a conductive piece through a transmission mechanism. The voltage difference between the two ends of the load switch can be eliminated, and therefore equipment is prevented from being burnt by electric arcs.

Description

Technical Field

[0001] The invention relates to the technical field of railway contact network, in particular to a contact network contact load switch with balanced potential and a use method thereof. Background Art

[0002] In the field of electrical equipment and contact network systems, contact network switches are one of the most important devices. Contact network is a mesh device that supplies power to electrified railways. It transmits electrical energy to trains to provide power for the operation of trains. During the operation of the contact network, the contact switch plays the role of connecting and disconnecting the circuit to ensure the normal supply and safe operation of electricity. The existing contact network switches mainly adopt the method of isolating switches, which are electrical equipment that can cut off the circuit and isolate electrical energy. Traditional isolating switches are realized by manual operation or electric operation, and the operation method is relatively simple. There are also some problems with traditional isolating switches in practical applications. First, due to the different lengths of the power supply arm, the running speed of the train, the load capacity, the number of trains, and other reasons, a voltage difference will occur on both sides of the switch. When the voltage difference is too large, the equipment will be discharged and burned. Secondly, traditional isolating switches cannot achieve autonomous monitoring and automatic operation, which limits their application scope and efficiency to a certain extent. In addition, the operation method of traditional isolating switches is relatively complicated and requires manual operation, which not only increases the labor intensity of operators, but also increases the safety risks during operation. Therefore, the problems or shortcomings of the existing technology in this field limit its effectiveness in practical applications, and a new technical solution is urgently needed to solve these problems. Summary of the invention

[0003] The purpose of the present invention is to provide a balanced potential contact network contact load switch and a use method, which is used to solve the problem that the existing contact network uses an isolating switch as a contact switch, and a voltage difference is easily generated on both sides of the switch, resulting in discharge and burning of equipment.

[0004] The technical solution adopted by the present invention to solve its technical problems is: a balanced potential contact network load switch, including a load switch, a transmission connecting rod and a control box, the load switch including a switch base, a wiring terminal A, a wiring terminal B and a conductive member, the wiring terminal A and the wiring terminal B are both relatively fixedly connected to the switch base, the conductive member is located between the wiring terminal A and the wiring terminal B, the switch base is also provided with a sensor A for detecting the voltage at the wiring terminal A, and a sensor B for detecting the voltage at the wiring terminal B, the control box is provided with a motor and a reducer, the output ends of the motor and the reducer are provided with a transmission shaft, the transmission shaft is fixedly connected to the lower end of the transmission connecting rod through a connecting member, and the upper end of the transmission connecting rod is connected to the conductive member through a transmission mechanism; after starting the motor and the reducer, the transmission shaft rotates to drive the transmission connecting rod to rotate, and then the conductive member is driven by the transmission mechanism to turn the wiring terminal A and the wiring terminal B on or off, thereby realizing the closing or opening of the load switch.

[0005] Furthermore, the wiring terminal A is fixed on the switch base through sensor A, and the wiring terminal B is fixed on the switch base through sensor B.

[0006] Furthermore, one end of the conductive member is hingedly connected to the sensor A and electrically connected to the terminal A. An arc-starting rod is provided above the terminal B. During the process of the conductive member connecting the terminal A and the terminal B, the other end of the conductive member first contacts the arc-starting rod to offset part of the arc.

[0007] Furthermore, a vacuum arc extinguishing chamber is provided above the connecting terminal B, and the arc-striking rod is located on the vacuum arc extinguishing chamber; when the load switch is closed, the end of the conductive member close to the vacuum arc extinguishing chamber contacts the arc-striking rod and drives the arc-striking rod to rotate, and the cam structure of the axis of the arc-striking rod triggers the vacuum arc extinguishing chamber to move, and at this time the vacuum arc extinguishing chamber is closed and the arc is extinguished, and then the conductive member is closed in place; when the load switch is opened, the conductive member drives the arc-striking rod to rotate in the opposite direction, and the cam structure of the axis of the arc-striking rod triggers the vacuum arc extinguishing chamber to move, and at this time the vacuum arc extinguishing chamber is opened and the arc is extinguished, and then the conductive member is separated from the arc-striking rod, and the opening is completed.

[0008] Furthermore, the lower end of the transmission shaft is fixedly connected to the output end of the motor and the reducer through a coupling, and the connecting member is a clamp located at the upper end of the transmission shaft, and the transmission shaft and the transmission connecting rod are relatively fixed by the clamp.

[0009] Furthermore, the transmission mechanism includes an active crank arm, a crank arm connecting rod, a first driven crank arm, a rotating shaft, a second driven crank arm and a pull rod insulator, the active crank arm is fixedly connected to the top of the transmission connecting rod, one end of the crank arm connecting rod is hinged to the active crank arm, the other end of the crank arm connecting rod is hinged to the first driven crank arm, and the first driven crank arm is fixed on the rotating shaft, the rotating shaft is rotatably connected to the base, the second driven crank arm is also fixed on the rotating shaft, and the second driven crank arm is hinged to the lower end of the pull rod insulator, and the upper end of the pull rod insulator is hinged to the conductive part; the rotation of the transmission connecting rod drives the rotation of the active crank arm, and then drives the rotation of the rotating shaft through the crank arm connecting rod and the first driven crank arm, and then drives the conductive part to swing through the pull rod insulator.

[0010] Furthermore, the control box is provided with a control panel, and the control panel is provided with a programmable controller, and the programmable controller is signal-connected with sensor A, sensor B, motor and reducer; the sensor A and sensor B upload the measured voltage signal to the programmable controller, and the programmable controller sends a signal to the motor and reducer to realize the opening and closing of the load switch.

[0011] Furthermore, the conductive member is a copper busbar, and the portion of the conductive member in contact with the connecting terminal A and the connecting terminal B is silver-plated.

[0012] The present invention also provides a method for using a balanced potential contact network load switch, comprising the following steps: S1, the sensor A monitors the voltage signal at the wiring terminal A in real time, the sensor B monitors the voltage signal at the wiring terminal B in real time, and uploads the monitored voltage signal to the programmable controller; S2, the programmable controller compares the received voltage signal. When the voltage difference between the terminal A and the terminal B rises slowly and exceeds the set threshold, the programmable controller sends a signal to the motor and the reducer to start the motor and the reducer, so that the conductive member swings to connect the terminal A and the terminal B, thereby closing the load switch to eliminate the voltage difference between the terminal A and the terminal B; when the voltage difference between the terminal A and the terminal B changes rapidly and the value is large, the programmable controller does not act; S3. The programmable controller continues to compare the received voltage signal. When the voltage difference between the terminal A and the terminal B is lower than the set threshold, the programmable controller again sends a signal to the motor and the reducer to start the motor and the reducer, so that the conductive part swings to disconnect the terminal A and the terminal B, so that the load switch returns to the open state.

[0013] The beneficial effects of the present invention are as follows: the present invention monitors the voltage at the load switch terminal A and the load switch terminal B in real time by setting the sensor A and the sensor B. When it is found that the voltage difference at the load switch terminal A and the load switch terminal B slowly rises and is higher than the set threshold, the load switch is closed to eliminate the voltage difference at the load switch terminal A and the load switch terminal B. The voltage difference problem caused by various reasons such as the different lengths of the power supply arms of the isolating switch is solved, and the discharge and burning of the equipment due to the voltage difference are avoided. This is in sharp contrast to the defect that the existing technology cannot solve the voltage difference, and greatly improves the safety and reliability of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A three-dimensional diagram of the present invention; Figure 2 It is a front view of the load switch of the present invention; Figure 3 A three-dimensional diagram of the control box of the present invention; Figure 4 It is a front view of the control box of the present invention; In the figure: 1 load switch, 11 vacuum interrupter, 12 arc-starting rod, 13 conductive part, 14 terminal A, 15 terminal B, 16 sensor A, 17 sensor B, 18 switch base, 2 transmission connecting rod, 3 control box, 31 clamp, 32 transmission shaft, 33 motor and reducer, 34 control panel, 35 box body, 4 active crank arm, 41 crank arm connecting rod, 42 first driven crank arm, 43 rotating shaft, 44 second driven crank arm, 45 pull rod insulator. DETAILED DESCRIPTION

[0015] like Figures 1 to 4 As shown, the contact switch of the present invention comprises a load switch 1, a transmission connecting rod 2 and a control box 3. The structure and working principle of the present invention are described below in conjunction with the accompanying drawings.

[0016] like Figures 1 to 4 As shown, a balanced potential contact network load switch of the present invention includes a load switch 1, a transmission connecting rod 2 and a control box 3. Figure 1 , Figure 2As shown, the load switch 1 includes a switch base 18, a terminal A14, a terminal B15 and a conductive member 13. The terminal A14 and the terminal B15 are both relatively fixedly connected to the switch base 18, and the switch base 18 is installed on a pillar along the railway. The conductive member 13 is located between the terminal A14 and the terminal B15. The switch base 18 also has a sensor A16 for detecting the voltage at the terminal A14, and a sensor B17 for detecting the voltage at the terminal B15. Specifically, the terminal A14 is fixed to the switch base 18 through the sensor A16, and the terminal B15 is fixed to the switch base 18 through the sensor B17. The sensor A16 not only fixes and supports the terminal A14, but also measures the voltage at the terminal A14. The sensor B17 not only fixes and supports the terminal B15, but also measures the voltage at the terminal B15. The lower end of the sensor A16 is fixedly connected to the switch base 18, and the upper end of the sensor A16 is used to fix the terminal A14. The lower end of the sensor B17 is fixedly connected to the switch base 18, and the upper end of the sensor B17 is used to fix the wiring terminal B15.

[0017] like Figure 2 As shown, one end of the conductive member 13 is hingedly connected to the sensor A16 and electrically connected to the terminal A14. An arc-starting rod 12 is provided above the terminal B15. When the conductive member 13 conducts the terminal A14 and the terminal B15, the other end of the conductive member 13 first contacts the arc-starting rod 12 to achieve a slight arc to offset a small amount of arc. A vacuum arc extinguishing chamber 11 is provided above the terminal B15. The arc-starting rod 12 is located on the vacuum arc extinguishing chamber 11. A cam-connecting rod transmission structure is provided between the arc-starting rod 12 and the vacuum arc extinguishing chamber 11. When the load switch is closed, one end of the conductive member 13 close to the vacuum arc extinguishing chamber 11 contacts the arc-starting rod 12 and drives the arc-starting rod 12 to rotate. The cam structure of the axis of the arc-starting rod 12 triggers the vacuum arc extinguishing chamber 11 to move. At this time, the vacuum arc extinguishing chamber 11 is closed and arc extinguished, and then the conductive member 13 is closed in place. Specifically, the conductive member 13 first contacts the arc-striking rod 12, and the swing of the conductive member 13 drives the fixed axis of the arc-striking rod 12 to rotate, and the cam on the fixed axis of the arc-striking rod 12 rotates, triggering the vacuum arc-extinguishing chamber 11 to operate through the connecting rod transmission, and extinguishing the arc. When the load switch 1 is closed, the arc between the conductive member 13 and the terminal B15 is partially offset by the arc-striking rod 12, and then the arc is quickly extinguished by the vacuum arc-extinguishing chamber 11, thereby avoiding the burning of the equipment due to the voltage difference when closing. When the load switch is opened, the conductive member 13 drives the arc-striking rod 12 to rotate in the opposite direction, and the cam structure of the axis of the arc-striking rod 12 triggers the vacuum arc-extinguishing chamber 11 to operate. At this time, the vacuum arc-extinguishing chamber 11 is opened and the arc is extinguished, and then the conductive member 13 is separated from the arc-striking rod, and the opening is completed.

[0018] like Figure 3 , Figure 4As shown, the control box 3 has a motor and a reducer 33, and the output end of the motor and the reducer 33 has a transmission shaft 32. The transmission shaft 32 is fixedly connected to the lower end of the transmission connecting rod 2 through a connecting member, and the upper end of the transmission connecting rod 2 is connected to the conductive member 13 through a transmission mechanism. After starting the motor and the reducer 33, the transmission shaft 32 rotates to drive the transmission connecting rod 2 to rotate, and then the conductive member 13 is driven by the transmission mechanism to turn the connection terminal A14 and the connection terminal B15 on or off, thereby realizing the closing or opening of the load switch. Specifically, the lower end of the transmission shaft 32 is fixedly connected to the output end of the motor and the reducer 33 through a coupling, and the connecting member is a clamp 31 located at the upper end of the transmission shaft 32, and the relative fixation of the transmission shaft 32 and the transmission connecting rod 2 is realized by the clamp 31. The clamp 31 is fixed to the upper end of the transmission shaft 32 through a pin, and the clamp 31 includes two clips, and the two clips provide a clamping torque through bolts to clamp and fix the lower end of the transmission connecting rod 2.

[0019] like Figure 1 As shown, the transmission mechanism includes an active crank arm 4, a crank arm connecting rod 41, a first driven crank arm 42, a rotating shaft 43, a second driven crank arm 44 and a pull rod insulator 45, the active crank arm 4 is fixedly connected to the top of the transmission connecting rod 2, one end of the crank arm connecting rod 41 is hingedly connected to the active crank arm 4, the other end of the crank arm connecting rod 41 is hingedly connected to the first driven crank arm 42, and the first driven crank arm 42 is fixed on the rotating shaft 43, and the rotating shaft 43 is rotatably connected to the switch base 18. The second driven crank arm 44 is also fixed on the rotating shaft 43, and the second driven crank arm 44 is hingedly connected to the lower end of the pull rod insulator 45, and the upper end of the pull rod insulator 45 is hingedly connected to the conductive member 13. The rotation of the transmission link 2 drives the rotation of the active crank arm 4, and then drives the rotation of the rotating shaft 43 through the crank arm link 41 and the first driven crank arm 42, and then the second driven crank arm 44 rotates with the rotating shaft 43, and then drives the swing of the conductive member 13 through the tie rod insulator 45. Moreover, when the transmission link 2 rotates clockwise, the tie rod insulator 45 pulls the conductive member 13 downward to achieve closing. When the transmission link 2 rotates counterclockwise, the tie rod insulator 45 pushes the conductive member 13 upward to achieve opening. The conductive member 13 is a copper bar, and the parts of the conductive member 13 that contact the terminal A14 and the terminal B15 are silver-plated.

[0020] like Figure 4 As shown, the control box 3 includes a box body 35, a control panel 34 is provided in the box body 35, and a programmable controller is provided on the control panel 34. The programmable controller is signal-connected with sensors A16, B17, and the motor and reducer 33. Sensors A16 and B17 upload the measured voltage signals to the programmable controller, and the programmable controller sends signals to the motor and reducer 33 to realize the opening and closing of the load switch. Sensors A16 and B17 can convert the kilovolt voltage into a low-voltage signal of 0-10V, and transmit it to the programmable controller as voltage signal collection.

[0021] The present invention also provides a method for using a balanced potential contact network load switch, comprising the following steps: S1, monitor the voltage signal at the wiring terminal A14 in real time through the sensor A16, monitor the voltage signal at the wiring terminal B15 in real time through the sensor B17, and upload the monitored voltage signal to the programmable controller; S2. The programmable controller compares the received voltage signal. When the voltage difference between the terminal A14 and the terminal B15 rises and exceeds the set threshold, the programmable controller sends a signal to the motor and reducer 33 to start the motor and reducer 33, thereby causing the conductive member 13 to swing to connect the terminal A14 and the terminal B15, thereby closing the load switch to eliminate the voltage difference between the terminal A14 and the terminal B15. When the voltage difference between the terminal A14 and the terminal B15 changes within 2S and reaches the rated voltage of the load switch, the programmable controller does not operate. For example, under normal circumstances, the load switch 1 is in the open state, and the sensor A 16 and the sensor B 17 monitor the voltage on the corresponding side of the load switch 1 in real time and continuously, and transmit the voltage signal to the programmable controller. When the voltage difference across the load switch rises to the set threshold of 24V, the programmable controller sends a signal to the control box 3 to control the load switch 1 to close, thereby eliminating the voltage difference across the load switch 1 (i.e., terminal A14 and terminal B15). After 5s, the programmable controller sends a signal to the control box 3 again to restore the load switch 1 to the open state. When the voltage difference rises rapidly to the rated voltage value of the load switch within 2s, the programmable controller does not send a signal to the motor and reducer 33 in the control box 3. At this time, the motor and reducer 33 do not operate, that is, no intervention is made in the voltage difference change across the load switch 1. When the voltage difference across the load switch 1 increases rapidly, such as when the line at one end of the load switch 1 needs to be shut down for maintenance, and the other end is operating normally, the maintenance side is instantly powered off, which is a normal operation. A large voltage difference instantly appears across the load switch 1, and the load switch 1 maintains the open state.

[0022] S3. The programmable controller continues to compare the received voltage signal. When the voltage difference between the terminal A14 and the terminal B15 is lower than the set threshold, the programmable controller again sends a signal to the motor and reducer 33 to start the motor and reducer 33, so that the conductive member 13 swings to disconnect the terminal A14 and the terminal B15, so that the load switch returns to the open state; when opening, the vacuum arc extinguishing chamber 11 first extinguishes the arc at the other end of the conductive member 13, and then the conductive member 13 is separated from the arc-starting rod 12 until the switch is completely opened.

[0023] In addition to solving the problem that the voltage difference in the prior art when using an isolating switch as a contact switch easily burns the equipment, the present invention also solves the problem that the contact switch in the prior art cannot monitor and operate automatically. The present invention sets sensors A16 and B17 to monitor the voltage at the load switch terminals A14 and B15 in real time. When it is found that the voltage difference at the terminals A14 and B15 rises slowly and is higher than the set threshold, the load switch is closed to eliminate the voltage difference at the terminals A14 and B15. The voltage difference problem caused by various reasons such as the different lengths of the power supply arms of the isolating switch is solved, and the discharge and burning of the equipment due to the voltage difference is avoided. This is in sharp contrast to the defect that the prior art cannot solve the voltage difference, and greatly improves the safety and reliability of the equipment.

[0024] The present invention can autonomously monitor the voltage, remotely control and automatically operate the switch by setting the sensor A16 and the sensor B17, which not only improves the operation efficiency but also expands the application scope. The isolating switch of the prior art cannot realize remote control and automatic operation, which limits its application scope and use efficiency to a certain extent. The operation mode is simplified, and the labor intensity and safety risks are reduced.

[0025] The operation mode of the present invention is relatively simple, and automatic operation is achieved through a programmable controller without manual operation, which not only reduces the labor intensity of the operator, but also reduces the safety risks during the operation. The isolating switch of the prior art requires manual operation, which not only increases the labor intensity of the operator, but also increases the safety risks during the operation.

[0026] The invention has a wide application scope and is suitable for the junction of existing lines and newly built lines. It can solve the current problem of frequent failures caused by large pressure differences. It has high technical and economic performance and has industrial prospects. However, the application scope of the isolating switch in the prior art is relatively limited and cannot adapt to complex working conditions. In general, the contact network contact switch of the invention has higher safety, reliability, operating efficiency and application scope than the prior art, and has significant advantages.

Claims

1. A balanced potential contact network load switch, characterized in that: The invention comprises a load switch, a transmission connecting rod and a control box. The load switch comprises a switch base, a wiring terminal A, a wiring terminal B and a conductive member. The wiring terminal A and the wiring terminal B are relatively fixedly connected to the switch base. The conductive member is located between the wiring terminal A and the wiring terminal B. The switch base is also provided with a sensor A for detecting the voltage at the wiring terminal A and a sensor B for detecting the voltage at the wiring terminal B. The control box is provided with a motor and a reducer. The output ends of the motor and the reducer are provided with a transmission shaft. The transmission shaft is fixedly connected to the lower end of the transmission connecting rod through a connecting member. The upper end of the transmission connecting rod is connected to the conductive member through a transmission mechanism. After starting the motor and the reducer, the transmission shaft rotates to drive the transmission connecting rod to rotate, and then the conductive member is driven by the transmission mechanism to connect or disconnect the wiring terminal A and the wiring terminal B, thereby realizing the closing or opening of the load switch.

2. The balanced potential contact network load switch according to claim 1, characterized in that: The wiring terminal A is fixed on the switch base through the sensor A, and the wiring terminal B is fixed on the switch base through the sensor B.

3. The contact network load switch with balanced potential according to claim 2, characterized in that: One end of the conductive member is hingedly connected to the sensor A and electrically connected to the terminal A. An arc-starting rod is provided above the terminal B. During the process of the conductive member conducting the terminal A and the terminal B, the other end of the conductive member first contacts the arc-starting rod.

4. The contact network load switch with balanced potential according to claim 3, characterized in that: A vacuum arc extinguishing chamber is provided above the connecting terminal B, and the arc-striking rod is located on the vacuum arc extinguishing chamber; when the load switch is closed, the end of the conductive member close to the vacuum arc extinguishing chamber contacts the arc-striking rod and drives the arc-striking rod to rotate, and the cam structure of the axis of the arc-striking rod triggers the vacuum arc extinguishing chamber to move, and the vacuum arc extinguishing chamber is closed and the arc is extinguished, and then the conductive member is closed in place; when the load switch is opened, the conductive member drives the arc-striking rod to rotate in the opposite direction, and the cam structure of the axis of the arc-striking rod triggers the vacuum arc extinguishing chamber to move, and the vacuum arc extinguishing chamber is opened and the arc is extinguished, and then the conductive member is separated from the arc-striking rod, and the opening is completed.

5. The contact network load switch with balanced potential according to claim 4, characterized in that: The lower end of the transmission shaft is fixedly connected to the output end of the motor and the reducer through a coupling, and the connecting piece is a clamp located at the upper end of the transmission shaft, through which the transmission shaft and the transmission connecting rod are relatively fixed.

6. A balanced potential contact network load switch according to claim 5, characterized in that: The transmission mechanism includes an active crank arm, a crank arm connecting rod, a first driven crank arm, a rotating shaft, a second driven crank arm and a pull rod insulator. The active crank arm is fixedly connected to the top of the transmission connecting rod, one end of the crank arm connecting rod is hinged to the active crank arm, the other end of the crank arm connecting rod is hinged to the first driven crank arm, and the first driven crank arm is fixed on the rotating shaft, the rotating shaft is rotatably connected to the base, the second driven crank arm is also fixed on the rotating shaft, and the second driven crank arm is hinged to the lower end of the pull rod insulator, and the upper end of the pull rod insulator is hinged to the conductive member; the rotation of the transmission connecting rod drives the rotation of the active crank arm, and then drives the rotation of the rotating shaft through the crank arm connecting rod and the first driven crank arm, and then drives the conductive member to swing through the pull rod insulator.

7. A balanced potential contact network load switch according to claim 6, characterized in that: The control box is provided with a control panel, and the control panel is provided with a programmable controller, and the programmable controller is signal-connected with sensor A, sensor B, the motor and the reducer; the sensor A and the sensor B upload the measured voltage signal to the programmable controller, and the programmable controller sends a signal to the motor and the reducer to realize the opening and closing of the load switch.

8. The balanced potential contact network load switch according to claim 7, characterized in that: The conductive member is a copper busbar, and the portion of the conductive member that contacts the connection terminal A and the connection terminal B is silver-plated.

9. The method for using a balanced potential contact network load switch according to claim 7, characterized in that: The following steps are involved: S1, the sensor A monitors the voltage signal at the wiring terminal A in real time, the sensor B monitors the voltage signal at the wiring terminal B in real time, and uploads the monitored voltage signal to the programmable controller; S2, the programmable controller compares the received voltage signal. When the voltage difference between the terminal A and the terminal B rises slowly and exceeds the set threshold, the programmable controller sends a signal to the motor and the reducer to start the motor and the reducer, so that the conductive member swings to connect the terminal A and the terminal B, thereby closing the load switch to eliminate the voltage difference between the terminal A and the terminal B; when the voltage difference between the terminal A and the terminal B changes rapidly and the value is large, the programmable controller does not act; S3. The programmable controller continues to compare the received voltage signal. When the voltage difference between the terminal A and the terminal B is lower than the set threshold, the programmable controller again sends a signal to the motor and the reducer to start the motor and the reducer, so that the conductive part swings to disconnect the terminal A and the terminal B, so that the load switch returns to the open state.

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