CN105513877A - Single-motor three-station actuator and mechanical locking protection device thereof - Google Patents

Abstract

The invention relates to a single-motor three-position operating mechanism and a mechanical locking protection device thereof, which include a limit turntable and a limit device. The opening stopper and the closing stopper limit the rotation direction of the limit turntable in the isolation closing and grounding opening. The closing stopper and the opening stopper have the opposite limit direction and their respective transmission connections are used to avoid them. The automatic resettable driving mechanism of the limit turntable and the elastic reset device for automatic reset, the closing stopper transmission connection is used to start the drive motor after the closing stopper is triggered when the isolation is closed and the ground is opened. When isolating the opening and closing of the ground, the limit turntable drives the closing block to trigger and then disconnects the first travel switch of the drive motor. The opening block is connected to the second stroke for the opposite effect of the first travel switch. The switch solves the problem of complex structure of the mechanical locking protection device of the current single-motor three-position operating mechanism.

Description

A single-motor three-position operating mechanism and its mechanical locking protection device

technical field

The invention relates to the field of a three-station operating mechanism, in particular to a single-motor three-station operating mechanism and a mechanical locking protection device thereof.

Background technique

With the development of science and technology, people combine the two independent components of the isolating switch and the grounding switch into a three-position combination component of the isolating/grounding switch. The combined GIS is smaller in size, and the operating mechanism after the combination of the two is also From the previous two-position mechanism that independently operated the isolation switch or the grounding switch, it becomes a three-position mechanism that can operate both the isolation switch and the grounding switch. The currently used three-station mechanism is roughly divided into two types. One is that two motors and two sets of driving devices synthesize one output through the crank sheave structure, that is, the dual-motor three-station mechanism. This three-station mechanism has two sets The driving device has complex structure, bulky size, high cost and difficult maintenance. The other is a single-motor three-position mechanism directly outputted by a set of driving devices with one motor, which has a simple structure and is easy to maintain.

When the single-motor three-position mechanism works, the motor drives the three-position isolating grounding switch to move after being decelerated by the transmission structure, and the forward and reverse rotation of the motor is controlled through the secondary circuit, thereby realizing the action of the three-position isolating and grounding switch. The traditional three-position electric operating mechanism, by installing a limit turntable on the output shaft, before the output shaft rotates in place, the limit turntable triggers the travel switch, cuts off the motor circuit, and connects the brake circuit, using the method of energy consumption braking , let the motor stop in a short time to control the output angle. Due to the differences in the windings of different motors, the same brake circuit will lead to uncertainty in the stop position of the motor and cause differences in the output angle of the mechanism. In order to ensure that the output angle meets the requirements of use, it is necessary to adjust the position of the travel switch and change the time for the motor to be powered off in advance. During the factory test, the position of the travel switch needs to be adjusted many times. The debugging efficiency is low, resulting in low production efficiency of the single-motor three-position mechanism. In addition, because there are certain risks in using the travel switch to cut off the motor circuit and dynamic braking, once the braking time of dynamic braking is too long or the travel switch fails, the motor will continue to drive the output shaft to rotate after the output shaft rotates in place. The moving contacts of the station isolating grounding switch continue to move under the drive of the mechanism. When closing, the moving and static contacts of the three-station isolating and grounding switch continue to move after overtravel, resulting in permanent damage to the moving and static contacts. Stopping at the correct position will cause the moving contact to deviate from the isolation end or the ground end, causing the distance between the moving and static contacts to be too small to cause insulation breakdown.

Contents of the invention

The purpose of the present invention is to provide a mechanical locking protection device for a single-motor three-position operating mechanism to solve the problem of the low debugging efficiency of the mechanical locking protection device for a single-motor three-position operating mechanism in the prior art and the inability to The problem of effectively protecting the switch body.

In addition, the purpose of the present invention is to provide a single-motor three-position operating mechanism.

The technical solution of the present invention is: a mechanical locking protection device for a single-motor three-position operating mechanism, including a limit turntable for anti-rotation and assembled on the output shaft of the single-motor three-position operating mechanism, and a limit limiter. The limit device for the rotation of the limit turntable, the limit device includes a closing stopper and an opening stopper respectively used to limit the rotation of the limit turntable in one direction, and the closing stopper isolates the closing and grounding of the limit turntable The rotation direction of the opening block is limited, the opening block is limited to the limit turntable in the rotation direction of the isolation opening and grounding closing, the closing block is opposite to the opening block, and the respective transmission connections are used for Drive the automatic resettable driving mechanism of the avoidance limit turntable and the elastic reset device for driving it to automatically reset. In addition, the closing stopper drive connection is used to be driven by the driving mechanism to close the switch when the isolation switch is closed and the ground is opened. After the stopper is triggered, the drive motor of the single-motor three-position operating mechanism is started, and the limit turntable drives the closing switch when the isolation opening and grounding are closed The first travel switch, the opening stopper transmission connection is used to drive the driving mechanism to drive the opening stopper to trigger the driving motor of the single-motor three-position operating mechanism when the isolation is opened and the ground is closed. When the grounding and grounding are opened, the limit turntable drives the opening block to trigger and then disconnects the second travel switch of the driving motor of the single-motor three-position operating mechanism.

The mechanical locking protection device of the single-motor three-position operating mechanism also includes a support block, and the support block is provided with a groove that cooperates with the closing block and the opening block. The guide hole for the guide fit of the brake stopper and the opening stopper.

One side of the groove is a block that is detachably and fixedly connected with the support block, the guide hole is set on the block, the guide hole is a long waist hole, the elastic reset device is fixed in the groove, and the closing block Both the block and the opening block are provided with a guide shaft that cooperates with the guide hole to make the elastic reset device in a pre-compressed state and limit the axial rotation of the limit block. The drive mechanism drives the closing block and the opening block through the guide shaft. Stoppers.

The groove is provided with a square groove mouth that guides and cooperates with the closing block and the opening block while restricting its axial rotation. The guide cooperates with the through hole for controlling the first and second stroke switches.

The drive mechanism is an electromagnet.

The limit turntable is provided with a limit shaft pin that cooperates with the limit device to limit the limit turntable.

A three-position operating mechanism with a single motor, including a mechanical lock protection device, the mechanical lock protection device includes a limit turntable for anti-rotation and assembled on the output shaft of the three-position operating mechanism with a single motor, and the mechanical lock protection The device also includes a limit device that limits the rotation of the limit turntable. The limit device includes a closing block and an opening block that are respectively used to limit the rotation of the limit turntable in one direction. The rotation direction limit of isolation closing and grounding opening, the opening stopper is limited to the limit turntable in the rotation direction of isolation opening and grounding closing, the limit direction of the closing stopper is opposite to that of the opening stopper and Each drive is connected with an automatic resettable drive mechanism for driving its avoidance limit turntable and an elastic reset device for driving it to automatically reset. The driving mechanism drives the closing block to trigger and then starts the driving motor of the single-motor three-position operating mechanism, and the limit turntable drives the closing block to trigger and then disconnects the single-motor three-position operating mechanism during isolation, opening and grounding closing. The first stroke switch of the driving motor of the moving mechanism, the transmission connection of the opening stopper is used to drive the driving mechanism to trigger the opening stopper to start the driving motor of the single-motor three-position operating mechanism when the opening is isolated and the grounding is closed. And when the isolation switch is closed and the ground switch is opened, the limit turntable drives the opening block to trigger and then disconnects the second travel switch of the driving motor of the single-motor three-position operating mechanism.

The mechanical locking protection device also includes a support block, the support block is provided with a groove that cooperates with the closing block and the opening block, and the groove is provided with a guide that is respectively connected with the closing block and the opening block. Fitting pilot holes.

One side of the groove is a block that is detachably and fixedly connected with the support block, the guide hole is set on the block, the guide hole is a long waist hole, the elastic reset device is fixed in the groove, and the closing block Both the block and the opening block are provided with a guide shaft that cooperates with the guide hole to make the elastic reset device in a pre-compressed state and limit the axial rotation of the limit block. The drive mechanism drives the closing block and the opening block through the guide shaft. Stoppers.

The limit turntable is provided with a shaft pin that cooperates with the limit device to limit the limit turntable.

The beneficial effects of the present invention are: the control system issues an isolation and closing command, and the driving mechanism that can automatically reset after receiving the command drives the closing stopper to close its limit function, and at the same time the closing stopper triggers the first A travel switch, the first travel switch switches the closed and disconnected state of the conductive circuit of the driving motor of the single-motor three-position operating mechanism, and the conductive circuit of the driving motor of the single-motor three-position operating mechanism is switched from the disconnected state to In the closed state, the driving motor of the single-motor three-position operating mechanism starts and drives the limit turntable to rotate. Since the drive mechanism maintains the limit action of the closing stopper and closes the set time, the limit turntable can pass through the closing stopper to limit the position. The drive mechanism resets automatically after the turntable passes the closing block, and at the same time, the elastic reset device drives the closing block to restore the limit state; since the opening block only limits the rotation direction of the limit turntable in the isolation opening and grounding closing, When the limit turntable passes through the opening block, it contacts with the opening block to close the limit function of the opening block. At the same time, the opening block triggers the second travel switch to switch the conduction of the driving motor of the single-motor three-position operating mechanism. In the closed and disconnected state of the circuit, the conductive circuit of the drive motor of the single-motor three-position operating mechanism is switched from the closed state to the open state. When the drive motor of the single-motor three-position operating mechanism is powered off, the brake circuit is started at the same time The driving motor of the single-motor three-position operating mechanism stops rotating in a short time. When the braking time is too long or the travel switch fails, the closing stopper will limit the limit turntable to ensure the safety of the switch body; similarly, isolation opening and grounding opening and closing can also realize the limit of the limit turntable. Through the one-way limiting effect of the opening and closing blocks on the limit turntable, the limit turntable is always within the set distance between the opening and closing blocks, ensuring the safety of the switch body and the accuracy of the output angle; 1. The cooperation of the closing block with the one-way limit function of the limit turntable can realize the limitation of the closing and opening positions of the limit turntable at the same time, so that the closing and opening positions of the limit turntable are at the same position. The structure is simple and easy to install and adjust. The efficiency is high, and the problems of low debugging efficiency of the mechanical locking protection device of the single-motor three-position operating mechanism in the prior art and failure to effectively protect the switch body when the mechanism fails are solved.

Furthermore, one side of the groove is a block that is fixedly and detachably connected to the support block, and the block is provided with guide holes that are respectively matched with the closing block and the opening block along the telescopic direction. The guide holes It is a long waist hole, and the elastic reset device is fixed in the groove. Both the closing block and the opening block are provided with a guide shaft that cooperates with the guide hole to make the elastic reset device in a pre-compressed state and limit the axial rotation of the block. The axial rotation of the stopper is limited while the stopper is guided to limit the stopper by the stopper, and the position of the limit end of the stopper can be adjusted by adjusting the position of the stopper, which facilitates the installation and disassembly of the elastic reset device.

Further, the groove is provided with a square groove opening that cooperates with the limit end of the opening and closing block to limit the axial rotation of the block, and the opening and closing of the opening and closing are divided by the cooperation between the square groove opening and the block. The axial rotation limit of the gate stopper is simple in structure and easy to process. At the same time, the movement direction of the opening and closing blocks can be controlled more precisely through the cooperation of the guide shaft and the block set on the opening and closing blocks and the double cooperation between the opening and closing blocks and the guide cooperation of the square groove opening. .

Furthermore, a pin shaft is arranged on the limit turntable, and the limit device limits the limit turntable through the limit pin shaft, which can improve the precision of the limit.

Description of drawings

Fig. 1 is a schematic diagram of the assembly structure of a specific embodiment 1 of a mechanical locking protection device of a single-motor three-position operating mechanism of the present invention;

Fig. 2 is the left view of Fig. 1;

Fig. 3 is a schematic diagram of the installation structure of opening and closing blocks in Fig. 1;

Fig. 4 is a schematic diagram of the appearance of the opening and closing blocks in Fig. 1;

Fig. 5 is a schematic diagram of the stopper installation structure in Embodiment 2 of a mechanical locking protection device of a single-motor three-position operating mechanism of the present invention;

FIG. 6 is a left side view of FIG. 5 .

detailed description

Specific embodiment 1 of a mechanical locking protection device for a single-motor three-position operating mechanism of the present invention: as shown in Figures 1-4, the mechanical locking protection device for a single-motor three-position operating mechanism includes The limit turntable 7, the limit device, the travel switch, the limit device includes a support block 2, a closing block 6, and an opening block 9, and the closing block 6 and the opening block 9 have opposite limiting directions and are respectively The transmission is connected with a driving mechanism for driving it to avoid the limit turntable 7 and automatically resets after working for a set time and an elastic reset device for driving it to automatically reset. The driving mechanism receives the signal from the single-motor three-position operating mechanism After starting to work, and automatically reset after working for a set time, the driving mechanism for driving the closing block 6 is an electromagnet 3, and the driving mechanism for driving the opening block 9 is an electromagnet 10, which is used to drive the closing block The automatic reset of the block 6 is the automatic reset spring 4, and what is used to drive the automatic reset of the closing block is the automatic reset spring 8. The electromagnet 3 and the electromagnet 10 are all fixed on the support block 2, and the automatic reset spring 4 and the automatic reset The spring 8 is a spring of the same specification, which are respectively fixed in the two square grooves of the support block 2. The two square grooves have the same structure. A circular through hole is arranged on the side opposite to the notch in the square groove. The diameter of the circular through hole is Less than the diameter of the automatic return spring 4, one side of the square groove is provided with a blocking plate, the blocking plate is provided with a long waist guide hole, and the blocking plate is fixed with the support block 2 screws.

The closing block 6 includes a limit end 61 that acts on the limit turntable 7 and a guide end 63 that cooperates with the square groove, and the opening block 9 includes a limit end 91 that acts on the limit turntable 7 and a guide end that cooperates with the square groove 93, the guide end 63 and the guide end 93 are all cylindrical structures, and the closing block 6 is provided with a guide shaft 62 cooperating with the long waist guide hole on the blocking piece 51 at the limit end 61, and the opening block 9 is all limited. The bit end is provided with a guide shaft 92 that cooperates with the long waist guide hole on the blocking piece 52 . The electromagnet 3 drives the closing block 6 through the guide shaft 62, and the leading end of the closing block 6 passes through the automatic return spring 4 and is installed on the circular through hole in the square groove. When the closing block 6 acts as a limiter, the guide shaft 62 is located at one end of the long waist hole on the block 51, and the automatic return spring 4 is in a pre-compressed state; when the electromagnet 3 drives the block to move in the square groove, the guide When the shaft 62 moves to the other end of the long waist hole, the closing stopper 6 is inside the square groove, and the limit dial 7 is not limited. The action of electromagnet 3 driving closing block 6 to move into the square groove is carried out through the instantaneous signal sent by the console, and the electromagnet 3 will automatically recover under the action of its internal return spring 4 within the set time after the signal is sent out. . The limit end of the closing block 6 cooperates with the guide of the square notch to limit the axial rotation of the closing block 6, and the guide shaft 62 provided on the closing block 6 cooperates with the stopper 51 and the limit of the closing block 6 The double cooperation between the bit end and the guide of the square notch can control the movement direction of the stopper more precisely. The structures of the opening stopper 9, the electromagnet 10, the guide shaft 92, the blocking plate 52, the automatic return spring 8 and the cooperation between them are the same as above, and will not be repeated.

There is a set distance between the closing stopper 6 and the opening stopper 9 to ensure that the output angle meets the requirements of use. The closing stopper 6 pairs the limit dial 7 with one-way limit in the clockwise movement direction, and the opening stopper 9 The one-way limit of the counterclockwise movement direction of the limit turntable 7, that is, the closing stopper 6 pairs with the limit turntable 7 to limit the rotation direction of the isolation closing and grounding opening, and the opening stopper 9 pairs with the limit turntable 7. Isolate the rotation direction limit of opening and grounding closing, through the unidirectional limit action of closing stopper 6 and opening stopper 9 on the limit turntable 7, the output accuracy of the operating mechanism can be guaranteed, and the number of factory debugging can be reduced ,Increase productivity. The travel switch includes a forming switch 1 and a travel switch 11. The travel switch 1 is connected to the closing block 6 in a driving manner, and is used to drive the closing block to be triggered by the driving mechanism to start the single-motor three-position operation when the switch is isolated and closed and the ground is opened. The driving motor of the moving mechanism is disconnected from the driving motor of the single-motor three-position operating mechanism by the limit turntable 7 when the closing block is triggered by the limit turntable 7 and the travel switch 11 is connected with the opening block 9 The transmission connection is used to drive the driving mechanism to drive the opening stopper 9 to trigger the driving motor of the single-motor three-position operating mechanism when the isolation switch is opened and the ground switch is closed, and the limit turntable is used when the isolation switch is closed and the ground switch is opened. 7. After the opening block is triggered, the driving motor of the single-motor three-position operating mechanism is disconnected. The braking circuit of the driving motor of the single-motor three-position operating mechanism starts at the same time after its own motor is disconnected. The related technology is the current There are technologies, so I won't repeat them here. The limit turntable 7 is provided with a limit pin 71, and the closing stopper 6 and the opening stopper 9 realize limiting the rotation of the limit turntable 7 by limiting the limit pin 71, and by limiting the limit pin 71, The limit accuracy can be improved.

During installation, the cylinder of the guide end 93 passes through the automatic return spring 8, and is installed in the square groove of the support block 2, and the cylinder of the stopper guide end 93 passes in the circular through hole in the square groove, and then the limit The guide shaft 92 of the end 91 passes through the long waist hole of the stopper 52, and the catch 52 is fixed on the support block 2 by screws, and the guide shaft 92 of the limit end 91 is limited by the stopper 52 long waist hole, The automatic return spring 8 has a certain pre-compression force, and the support block 2 overcomes the pre-compression force of the return spring 8 under the force of the electromagnet and can slide in the square groove along the groove wall of the support block 2. When the force of the electromagnet disappears, the Under the action of the reset force of the back-moving spring 8, the opening block 9 slides outside the square groove along the groove wall, and finally stops under the limit of the other end of the long waist hole of the blocking piece 52. The installation method of the closing block 6 is the same as that of the opening block 9, and will not be repeated. Connect the limiting turntable 7 in the mechanical locking protection device of the single-motor three-position operating mechanism with the output shaft of the single-motor three-position operating mechanism, and the rotation of the output shaft can drive the limit turntable 7 to rotate axially.

The current position shown in Figure 1 is the opening position of the three-position isolation grounding switch. When the control system issues an isolation closing command, the electromagnet 3 is charged and closed, driving the closing block 6 to move in the square groove, and the guide end 63 is pressed. The travel limit switch 1 is triggered, and after the travel switch 1 is triggered, the driving motor circuit of the single-motor three-position operating mechanism is connected, and the driving motor drives the output shaft of the single-motor three-position operating mechanism and the limit turntable 7 Turn clockwise in the direction shown in the installation diagram. Since the electromagnet is in the state of attraction, the limit end 61 of the closing block 6 is in the square groove, and the limit turntable 7 can pass through clockwise. Since the attraction of the electromagnet is controlled After receiving the signal, the electromagnet remains in the closed state for a set time and then disconnects. Under the action of the return spring inside it, it automatically recovers. The closing stopper 6 is under the action of the automatic return spring 4 Move out of the square groove to return to the limit state. When the limit dial 7 rotates clockwise to contact with the slope of the opening block 9, since the opening block 9 only limits the counterclockwise rotation direction of the limit dial 7, the limit dial 7 can pass through the opening block. 9. When the limit turntable 7 passes through the opening block 9, the limit turntable 7 pushes the opening block 9 to move in the square groove, and the opening block 9 triggers the travel switch 11 to switch the drive of the single-motor three-position operating mechanism In the working state of the motor, the driving motor circuit of the single-motor three-position operating mechanism is disconnected, and the brake circuit is connected at the same time. The opening block 9 automatically returns to the limit state under the action of the automatic return spring 8, the driving motor of the single-motor three-position operating mechanism stops in a short time, the single-motor three-position operating mechanism stops operating, and the isolation switch Closing action ends. It is an existing technology to start the brake circuit while the driving motor of the single-motor three-position operating mechanism is disconnected, and will not be described in detail here. When the driving motor of the single-motor three-position operating mechanism brakes normally, the limit pin 71 on the limit turntable 7 stops between the closing block 6 and the opening block 9; when the braking time is too long, the limit The upper limit pin 71 of the turntable 7 and the closed stopper 6 are limited to stop, and the driving motor of the single-motor three-position operating mechanism stops, which ensures the output accuracy of the operating mechanism; when the brake circuit fails or the travel switch 11 If a fault occurs, the drive motor circuit of the single-motor three-position operating mechanism cannot be powered off, the upper limit pin 71 of the limit turntable 7 is limited by the closing stopper 6, and the output shaft of the mechanism will no longer rotate, ensuring the isolation of the grounding switch body unharmed. After the isolation and closing action is completed, the state of the mechanical locking protection device is the same as that of the opening. On the contrary, when the isolation switch is opened, the action principle is the same as that of the isolation switch. The driving motor action of the single-motor three-position operating mechanism drives the output shaft of the operating mechanism and the limit turntable 7 to rotate counterclockwise in the direction shown in the installation diagram. Similarly, the action sequence and principle of grounding closing and isolation opening are the same, and the action sequence and principle of grounding opening and isolation closing are the same.

Embodiment 2: The difference between this embodiment and Embodiment 1 is only that: as shown in Figure 5 and Figure 6, the baffle piece is not provided with a long waist hole, and the guide shaft of the stopper is arranged at the end in contact with the travel switch. The notch of the square groove on the support block is provided with a pair of relative limit flanges. When the automatic return spring is installed in the square groove, the automatic return spring has a certain pre-compression force under the limit of the limit flanges. Other parts of the implementation are the same as those in Embodiment 1 and will not be repeated here.

In other embodiments of the present invention, the automatic return spring described in the above embodiment can also be a disc spring, a torsion spring cooperating with the support block and the stopper; the described relay can also be controlled by a PLC control device, a motor 1. The driving mechanism composed of the crank slider mechanism, the PLC control device controls the motor to drive the crank slider mechanism to move within the set time meeting the requirements; the stopper can also swing left and right under the drive of the driving device and realize one-way Limiting; the axial rotation limit of the block can also be limited only by the long waist hole on the block and the guide shaft or only by the limit end of the block and the inner wall of the square groove. The limit turntable described above can also not be provided with a limit pin shaft, and the limit device can directly limit the limit turntable; the number of the square slots can also be one, and the stopper of the square slot is provided with two lengths that match the stoppers. Waist guide hole, the opposite side of the square notch is provided with two circular through holes that cooperate with the guide end of the block; the square groove can also be a composite groove with a square notch and a circular bottom, or It is a circular groove, a diamond groove, a hexagonal groove, etc.; the support block can also be omitted, and the mechanical locking protection device of the single-motor three-position operating mechanism is directly installed on the three-position mechanism; The shape of the opening and closing block can also be a sickle shape.

A specific embodiment of a single-motor three-position operating mechanism of the present invention: the single-motor three-position operating mechanism includes a mechanical locking protection device, and the structure and function of the mechanical protection device are the same as those of the above-mentioned single-motor three-position operating mechanism. The structures and functions described in the embodiment of the mechanical protection device of the three-position operating mechanism are the same, and will not be repeated here.

Claims (10)

1. A mechanical locking protection device for a single-motor three-position operating mechanism, comprising a limit turntable mounted on the output shaft of a single-motor three-position operating mechanism for anti-rotation, characterized in that: it also includes a limit limit The limit device for the rotation of the turntable. The limit device includes a closing stopper and an opening stopper respectively used to limit the rotation of the limit turntable in one direction. The closing stopper isolates the closing and grounding of the limit turntable. The limit of the rotation direction of the gate, the opening stopper is limited to the limit turntable in the rotation direction of isolation opening and grounding closing, the limit direction of the closing stopper is opposite to that of the opening stopper, and the respective transmission connections are used to drive It avoids the automatic resettable driving mechanism of the limit turntable and the elastic reset device for driving it to automatically reset. In addition, the closing stopper transmission connection is used for driving the closing stopper by the driving mechanism when isolating closing and grounding opening. After the block is triggered, the driving motor of the single-motor three-position operating mechanism is started, and the limit turntable is driven by the limit turntable to trigger the closing block, and the driving motor of the single-motor three-position operating mechanism is disconnected after the block is triggered. The first travel switch is connected to the transmission of the opening block and is used to drive the driving mechanism to trigger the opening block to trigger the driving motor of the single-motor three-position operating mechanism when the isolation is opened and the ground is closed. When grounding and opening, the limit turntable drives the opening block to trigger, and then disconnects the second travel switch of the driving motor of the single-motor three-position operating mechanism. 2. The mechanical locking protection device of the single-motor three-position operating mechanism according to claim 1, characterized in that: the mechanical locking protection device of the single-motor three-position operating mechanism further includes a support block, a support block There are grooves on the top to guide and cooperate with the closing block and the opening block, and guide holes are arranged in the grooves to guide and cooperate with the closing block and the opening block respectively. 3. The mechanical locking protection device of the single-motor three-position operating mechanism according to claim 2, characterized in that: one side of the groove is a block that is fixedly and detachably connected to the support block, and the The guide hole is set on the block, the guide hole is a long waist hole, the elastic reset device is fixed in the groove, the closing block and the opening block are provided with guide holes to make the elastic reset device in a pre-compressed state and A guide shaft that restricts the axial rotation of the limit block, and the drive mechanism drives the closing block and the opening block through the guide shaft. 4. The mechanical locking protection device of the single-motor three-position operating mechanism according to claim 2 or 3, characterized in that: the groove is provided with a guide that cooperates with the closing stopper and the opening stopper to simultaneously limit The axially rotating square groove opening is provided with a through hole on the opposite surface of the groove opening for cooperating with the closing stopper and the opening stopper guide to control the first and second stroke switches. 5. The mechanical locking protection device of a single-motor three-position operating mechanism according to any one of claims 1-3, wherein the driving mechanism is an electromagnet. 6. The mechanical locking protection device of the single-motor three-position operating mechanism according to any one of claims 1-3, characterized in that: the limit turntable is provided with a pair of limit switches that cooperate with the limit device. The limit shaft pin of the turntable limit. 7. A single-motor three-station operating mechanism, including a mechanical locking protection device, the mechanical locking protection device includes a limit turntable for anti-rotation assembly on the output shaft of the single-motor three-station operating mechanism, which It is characterized in that: the mechanical locking protection device further includes a limit device that limits the rotation of the limit turntable, and the limit device includes a closing stopper and an opening stopper respectively used to limit the rotation of the limit turntable in one direction, The closing stopper limits the rotation direction of the limit turntable in the isolation closing and grounding opening, the opening stopper limits the rotation direction of the limit turntable in the isolation opening and grounding closing, the closing stopper and the opening The limit directions of the brake blocks are opposite and each drive is connected with an automatic resettable drive mechanism for driving it to avoid the limit turntable and an elastic reset device for driving it to automatically reset. When isolation closing and grounding closing, the driving mechanism drives the closing stopper to trigger, and then starts the driving motor of the single-motor three-position operating mechanism, and when the isolation opening and grounding closing, the limit turntable drives the closing stopper to trigger After disconnecting the first travel switch of the driving motor of the single-motor three-position operating mechanism, the transmission connection of the opening block is used to start the single motor after the driving mechanism drives the opening block to trigger when the isolation is opened and the ground is closed. The driving motor of the three-station operating mechanism is disconnected from the second travel switch of the driving motor of the single-motor three-station operating mechanism after being triggered by the limit turntable to trigger the opening block when the switch is isolated and closed and grounded. 8. The single-motor three-position operating mechanism according to claim 7, characterized in that: the mechanical locking protection device also includes a support block, and the support block is provided with a closing stopper and an opening stopper guide A cooperating groove, the groove is provided with a guide hole that guides and cooperates with the closing block and the opening block respectively. 9. The single-motor three-position operating mechanism according to claim 8, characterized in that: one side of the groove is a block that is fixedly and detachably connected to the support block, and the guide hole is set at On the stopper, the guide hole is a long waist hole, and the elastic reset device is fixed in the groove. Both the closing block and the opening block are equipped with guide holes to make the elastic reset device in a pre-compressed state and limit the axis of the limit block. To the rotating guide shaft, the drive mechanism drives the closing stopper and the opening stopper through the guide shaft. 10. The single-motor three-position operating mechanism according to any one of claims 7-9, characterized in that: the limit turntable is provided with a shaft that cooperates with the limit device to limit the limit turntable pin.