A moving contact unloading and shifting no-field drum-type distribution switch with in-place feel

Abstract

The application provides a drum-type tap changer with a to-position feeling and a movable contact unloading after shifting, which comprises two mounting plates, a center shaft, a static contact, a gear system, a groove wheel system, a movable contact support, a movable contact system, a cam and a spring assembly; the cam is fixed on the center shaft and rotates synchronously with the center shaft; a large head capable of cyclically contacting the movable contact system and a small head not contacting the movable contact system are arranged at two ends of the cam respectively, and a recess is arranged in the middle of the large head; the spring assembly comprises a support, a support ring and a return spring; the support is fixed on the movable contact system; the support ring is rotatably arranged on the center shaft; and the return spring is connected between the support and the support ring. The application can ensure reliable contact between the movable contact and the static contact in a working state, and can easily shift gears when the gears are stable and shifted, and the to-position feeling is obvious and strong in the shifting process.

Description

Technical Field

[0001] This invention belongs to the technical field of non-excitation drum-type tap changers, specifically relating to a non-excitation drum-type tap changer with a tactile feel for unloading the moving contact and shifting gears. Background Technology

[0002] Currently, there are two main types of moving contact structures for non-excitation drum tap changers on the market: one is a rolling ring moving contact structure, and the other is a contact structure that allows for easy shifting after the moving contact is unloaded.

[0003] For a pure rolling ring moving contact mechanism, this structure is limited by its design. If the moving contact ring is made too small, the torque will increase; if the moving contact ring is made too large, the insulation distance between it and the adjacent contact will be shortened. Therefore, the moving contact ring cannot be made too large, which leads to a large switching torque. Thus, the obvious drawback of this structure is that the switching torque is large and the ring contact is prone to deformation. Furthermore, this structure has the least spring force when the contacts are in contact, but the greatest spring pressure when shifting gears. This is something we should try our best to avoid when making switches.

[0004] For tap changers with easy shifting contact structure after moving contact unloading, reliable and stable contact between the moving and stationary contacts is guaranteed under normal operating conditions (maximum contact pressure). The tap changer can easily shift positions when changing gears (contact pressure unloaded, low torque). This product is a rising star, possessing advantages such as easy shifting after moving contact unloading, contact at maximum contact pressure, low torque, and reliable positioning. However, some users are accustomed to using non-excited drum tap changers with a pure rolling ring moving contact mechanism (these non-excited drum tap changers can spring to the next gear after manual operation with excessive force past the dead point, providing a strong tactile feedback). Therefore, when switching to a non-excited drum tap changer with easy shifting contact structure after moving contact unloading, the less noticeable tactile feedback during manual shifting can cause confusion for users, making it uncertain whether a shift has been completed. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a drum-type tap changer with a tactile feedback mechanism that allows for shifting without excitation after unloading of the moving contact.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A tactilely responsive, unloaded, de-energized drum-type tap changer includes two mounting plates, a vertically mounted central shaft rotatably mounted on both plates, multiple stationary contacts vertically fixed between the two mounting plates and evenly distributed outside the central shaft, a gear system mounted on one of the mounting plates and rotating with the central shaft, a Geneva system rotatably mounted on the central shaft and rotating with the gear system, a moving contact bracket rigidly connected to the Geneva system and rotating with the Geneva system, and a moving contact system slidably mounted on the moving contact bracket and rotating with the moving contact bracket. The moving contact system is used to connect any two adjacent stationary contacts. In addition to the above structure, the tactilely responsive, unloaded, de-energized drum-type tap changer further includes:

[0008] A cam, corresponding to the moving contact system, is fixed on a central shaft and rotates synchronously with the central shaft. At each end of the cam are a large end that circumferentially contacts the moving contact system and a small end that does not. A groove is provided in the middle of the large end that engages with the moving contact system. During the synchronous rotation of the cam with the central shaft, when the groove in the middle of the large end contacts and engages with the moving contact system, the cam pushes the contact system towards the stationary contact, pressing the moving contact system firmly against two adjacent stationary contacts.

[0009] A spring assembly, comprising at least one spring assembly, each spring assembly including a support member, a support ring, and a return spring; the support member is fixed to the moving contact system; the support ring is rotatably mounted on a central shaft; and the return spring is connected between the support member and the support ring. The function of the spring assembly is to pull the moving contact system back during gear shifting, reducing the resistance during the rotation of the moving contact system.

[0010] When the groove of the cam begins to contact the moving contact system, the moving contact system automatically engages fully with the groove of the cam due to the interaction between the groove and the spring, forcing the central shaft to automatically return to its original position, thus making the switch fully engaged with a strong tactile feel.

[0011] Furthermore, the moving contact system includes a contact support, a roller, a pin, and a moving contact assembly. The contact support is slidably mounted on the moving contact support and can slide towards or away from the stationary contact. The contact support is C-shaped, with its open end facing the stationary contact and its closed end facing the central axis. The roller is rotatably mounted on the side of the closed end of the contact support facing the central axis via a vertically arranged pin, and the roller can mesh with the groove of the cam head. The pin is vertically fixed inside the open end of the contact support. The moving contact assembly includes multiple moving contacts stacked vertically and sleeved outside the pin. Each moving contact has an oblong hole with a length greater than the diameter of the pin along the sliding direction of the contact support. The moving contact can slide back and forth along the oblong hole and can connect two of the stationary contacts. A spring is connected between each moving contact and the inner wall of the closed end of the contact support.

[0012] Furthermore, the number of rollers is two and they are symmetrically arranged on the side of the closed end of the contact support facing the central axis; each roller is cylindrical and can stably engage with the groove on the cam head.

[0013] Furthermore, there are two spring assemblies symmetrically arranged between the contact support and the central shaft, and the support of each spring assembly is fixed on the closed end of the contact support.

[0014] Furthermore, the mounting plate includes a horizontally arranged upper mounting plate and a lower mounting plate; the stationary contacts are multiple (generally 6, 8, or 10) copper rod contacts evenly distributed on the same circumference outside the central shaft; the gear system includes gear one, a drive shaft, and gear two; gear one is fixed on the central shaft; the drive shaft is vertically and rotatably mounted on the upper mounting plate; gear two is fixed on the drive shaft and meshes with gear one; the Geneva system includes a slotting element and a Geneva wheel, the slotting element being fixed on the drive shaft... The gear rotates synchronously with the shaft; the grooved wheel is rotatably mounted on the central shaft and can rotate under the action of the grooving component; the moving contact bracket includes an upper support, a lower support, and a connecting member; the upper support is fixedly connected to the grooved wheel and can rotate with the grooved wheel; the lower support is rotatably mounted on the central shaft; the connecting member is fixedly connected between the upper support and the lower support; slide rails are symmetrically provided at the bottom of the upper support and the top of the lower support; the upper and lower ends of the contact bracket are slidably mounted on the slide rails and slide along the slide rails between the stationary contact and the central shaft.

[0015] Furthermore, the grooved wheel is an embedded grooved wheel with multiple circumferentially distributed locking grooves evenly provided on its inner side; the lower end of the corresponding chuck extends into the grooved wheel and has a locking circle on its lower side that can engage with the locking groove; each time the chuck rotates, the locking circle on its outer side rotates one revolution and chucks the grooved wheel once, causing the grooved wheel to rotate and drive the moving contact bracket connected to it to rotate synchronously, so that the moving contact system in the moving contact bracket contacts two different adjacent stationary contacts.

[0016] Furthermore, the transmission ratio between gear one and gear two is n:(n+1), where n is a natural number greater than 2, and the number of stationary contacts is equal to n+1.

[0017] Furthermore, when the moving contact disengages from the stationary contact, the distance from the center of the central shaft to the large end of the cam is greater than the distance from the center of the central shaft to the closed end of the contact support, so as to ensure that the cam applies sufficient pressure to the moving contact to press the moving contact against two adjacent stationary contacts.

[0018] Furthermore, the unloaded shifting drum-type tap changer with a tactile feel also includes a shielding cover, which is mounted on the upper mounting plate and places the gear system in the middle. This shielding cover is used to shield the electric field distribution at the tip of the gear system and improve the internal insulation performance of the switch.

[0019] Furthermore, the de-energized drum-type tap changer with a tactile feel for unloading and shifting gears also includes a gear position display device. The gear position display device is disc-shaped and fixed on a central shaft, rotating synchronously with the central shaft. Gear position numbers for indicating the gear position are sprayed on the gear position display device.

[0020] The beneficial effects of this invention are as follows:

[0021] The implementation of this invention provides a more pronounced tactile feedback for the unloaded, easily shifting tap changer with a no-excitation drum-type contact structure, making it more suitable for users' regular operating habits. It improves the reliable contact performance between the moving and stationary contacts, reduces shifting torque (easy manual shifting), and removes foreign objects from the contacts (e.g., non-conductive carbon deposits, other non-conductive substances in the transformer oil), further enhancing the overall performance of the product. Simultaneously, it ensures reliable and stable contact between the moving and stationary contacts during operation (maximum contact pressure), and allows for easy shifting (contact pressure unloaded, low torque), with a clear and strong tactile feedback during shifting. Attached Figure Description

[0022] The present invention will now be described in further detail with reference to the accompanying drawings.

[0023] Figure 1 This is a main sectional view of the present invention;

[0024] Figure 2 This is a top sectional view of the contact system of the present invention;

[0025] Figure 3 This is a diagram illustrating the operation process of the contact system of the present invention;

[0026] The figure shows: 1-Upper mounting plate, 2-Lower mounting plate, 3-Central shaft, 4-Stationary contact, 5-Gear 1, 6-Gear 2, 7-Drive shaft, 8-Shielding cover, 9-Coupling, 10-Groogging part, 11-Groogging wheel, 12-Upper support, 13-Lower support, 14-Connector, 15-Contact bracket, 16-Roller, 17-Pin, 18-Pin shaft, 19-Moving contact, 20-Spring, 21-Cam, 22-Support ring, 23-Support part, 24-Reset spring, 25-Gear position display device. Detailed Implementation

[0027] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings of this specification are merely for illustrative purposes to aid those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0029] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Example 1

[0030] like Figure 1 As shown, this embodiment provides a de-energized drum-type tap changer with a tactile feedback after unloading of the moving contact, comprising:

[0031] The mounting plate includes an upper mounting plate 1 and a lower mounting plate 2 arranged horizontally; the upper mounting plate 1 and the lower mounting plate 2 are parallel to each other and are the main support and insulation components of the tap changer, serving as the skeleton of the entire product.

[0032] A central shaft 3 is vertically arranged (between the upper mounting plate 1 and the lower mounting plate 2) and its two ends are rotatably mounted on the upper mounting plate 1 and the lower mounting plate 2 respectively via bearings; the upper end of the central shaft 3 penetrates the upper mounting plate 1 and extends above the upper mounting plate 1, and a coupling 9 (connected to the drive system) is provided at the upper end of the central shaft 3 to provide rotational torque to the gear system of the switch and the cam 21.

[0033] The stationary contact 4 consists of multiple (generally 6, 8, or 10) copper rod contacts that are vertically fixed between the upper mounting plate 1 and the lower mounting plate 2 and evenly distributed on the same circumference outside the central shaft 3; both ends of the stationary contact 4 are connected to the transformer winding.

[0034] The gear system includes a first gear 5, a drive shaft 7, and a second gear 6. The first gear 5 is fixed on the central shaft 3 and is used to transmit power to the Geneva system. The drive shaft 7 is vertically arranged and rotatably mounted on the upper mounting plate 1 through bearings. The upper end of the drive shaft 7 penetrates the upper mounting plate 1 and extends above it. The second gear 6 is fixed on the upper end of the drive shaft 7 and meshes with the first gear 5. The transmission ratio between the first gear 5 and the second gear 6 is 5:6, and the corresponding number of stationary contacts is six.

[0035] The Geneva system includes a grooved element 10 and a Geneva wheel 11. The grooved element 10 is fixed on the transmission shaft 7 (lower end) and rotates synchronously with the gear 6. The Geneva wheel 11 is rotatably mounted on the central shaft 3 via a bearing and can rotate under the action of the grooved element 10. The Geneva wheel 11 is an embedded Geneva wheel with multiple circumferentially distributed locking grooves evenly provided on its inner side. Correspondingly, the lower end of the grooved element 10 extends into the Geneva wheel 11, and a locking circle that can engage with the locking grooves is provided on the lower side of the grooved element 10. The grooved element 10 rotates within the inner cavity of the Geneva wheel 11, causing the Geneva wheel 11 to rotate by a preset angle. For each rotation of the grooved element 10, the locking circle on its outer side rotates one revolution and moves the Geneva wheel 11 once, causing the Geneva wheel 11 to rotate and drive the moving contact bracket, which is integrated with the Geneva wheel 11, to rotate synchronously, so that the moving contact system in the moving contact bracket contacts two adjacent stationary contacts 4.

[0036] The moving contact support includes an upper support 12, a lower support 13, and a connecting member 14, which drives the moving contact system to rotate with the moving contact support. The upper support 12 is fixedly connected to the grooved wheel 11 (rigid connection, connecting the moving contact support and the grooved wheel into a rigid body) and can rotate with the grooved wheel 11; the lower support 13 is rotatably mounted on the central shaft 3 via a bearing; the connecting member 14 is fixedly connected (rigid connection) between the upper support 12 and the lower support 13, and the three are rigidly connected to form a whole; symmetrical slides are provided at the bottom of the upper support 12 and the top of the lower support 13; the slides are arranged along the line connecting the stationary contact 4 and the central shaft 3.

[0037] The moving contact system includes a contact support 15, rollers 16, a pin 18, and a moving contact assembly. The contact support 15 is slidably mounted on the moving contact support and can slide towards or away from the stationary contact (specifically, the upper and lower ends of the contact support are slidably mounted on the slide rails of the upper support 12 and the lower support 13, respectively, and slide along the slide rails between the stationary contact 4 and the central shaft 3). The contact support 15 is C-shaped, with its open end facing the stationary contact 4 and its closed end facing the central shaft 3. There are two rollers 16, symmetrically arranged on the side of the closed end of the contact support 15 facing the central shaft 4. Each roller 16 is rotatably mounted on the closed end of the contact support 15 via a vertically arranged pin 17. Each roller 16 is cylindrical and engages with the groove 213 of the large head 211 of the cam 21. Two pins 18 are vertically fixed inside the open end of the contact support 15. The moving contact assembly includes multiple moving contacts 19 stacked together and sleeved outside the two pins 18. Each moving contact 19 has a slotted hole with a length greater than the diameter of the pin 18 along the sliding direction of the contact support 15. The moving contact 19 can slide back and forth along the slotted hole and connect two adjacent stationary contacts 4. A spring 20 is connected between each moving contact 19 and the inner wall of the closed end of the contact support 15, providing contact pressure between the contacts (moving contact 19 and stationary contact 4). The function of the moving contact 19 is to connect two different adjacent stationary contacts 4, thereby changing the transformer winding and thus achieving transformer voltage regulation.

[0038] Cam 21 is fixed on the central shaft 3 (preset position) and rotates synchronously with the moving contact system. At both ends of cam 21 are a large end 211 that can circumferentially contact the moving contact system and a small end 212 that does not contact the moving contact system. Both the large end 211 and the small end 212 are arc-shaped, with the arc diameter of the large end 211 being larger than that of the small end 212. A groove 213 that can engage with the moving contact system is provided in the middle of the large end 211. During the synchronous rotation of cam 21 with the central shaft 3, when the arc surface of the large end 211 contacts and engages with the moving contact system (roller 16), cam 21 pushes the contact system to slide towards the stationary contact 4, pushing the moving contact system to the preset position, so that the moving contact 19 of the moving contact system is pressed against the two adjacent stationary contacts 4. When the moving contact 19 disengages from the stationary contact 4, the distance from the center of the central shaft 3 to the end of the large head 211 of the cam 21 is greater than the distance from the center of the central shaft 3 to the closed end of the contact support 15, so as to ensure that the cam 21 gives the moving contact 19 sufficient pressure to press the moving contact 19 against the two adjacent stationary contacts 4.

[0039] The spring assemblies consist of two symmetrically arranged between the contact support 15 and the central shaft 3. Each spring assembly includes a support member 23, a support ring 22, and a return spring 24. The support member 23 is fixed to the closed end of the contact support 15 of the moving contact system. The support ring 22 is rotatably mounted on the central shaft 3 via a bearing or bushing. The return spring 24 connects the support member 23 and the support ring 22. The function of the spring assemblies is to pull the moving contact system back during gear shifting, reducing the resistance during the rotation of the moving contact system.

[0040] When the switch is in operation, the contact support 15 of the moving contact system is rigidly connected to the grooved wheel 11. The locking groove of the grooved wheel 11 engages with the locking circle of the pusher 10, preventing the grooved wheel 11 from rotating at a fixed angle position, thus ensuring the precise positioning of the moving contact system. The large end 211 of the cam 21 contacts the roller 16, which pushes the moving contact system (towards the stationary contact 4) to its maximum position, forcing the moving contact 19 of the moving contact system to be in close contact with the stationary contact 4. At this time, the spring 20 is compressed to a large extent, thereby maximizing the contact pressure between the moving contact 19 and the stationary contact 4, ensuring reliable contact. When the switch is operated manually, the roller 16 is engaged in the groove 213 in the middle of the large end 211 of the cam 21, which prevents the central shaft 3 from rotating arbitrarily. This ensures that the switch is accurately positioned, does not deflect, and has a strong tactile feel when in position. When the switch is operated manually, the large end 211 of the cam 21 has a wide range, and the rotational accuracy of the central shaft 3 is within ±30° to ensure reliable contact of its contacts. Furthermore, the groove wheel 8 will not move within ±30°. Therefore, the installation error and deflection error of the switch central shaft 3 described in this embodiment can be greatly reduced, thereby ensuring more reliable operation.

[0041] Gear shifting process:

[0042] Since the transmission ratio of gear 5 to gear 6 is 5:6, when the central shaft rotates 50°, gear 5 and cam 21 also rotate 50°, and gear 6 and the shifting piece 10 rotate 60°. At this time, the large head 211 of cam 21 leaves the roller 16, and the moving contact system is pulled back by the spring assembly (by the return spring 24), and the moving contact group disengages from the stationary contact 4. Next, the central shaft 3 continues to rotate. When the central shaft 3 rotates to 200°, gear 5 and cam 21 also rotate 200°, and gear 6 and the shifting piece 10 rotate 240°. At this time, the grooved wheel 11 rotates 60°, taking the moving contact system with it and rotating it 60° to the correct position of the next gear. At this moment, the locking groove of the grooved wheel 11 engages with the locking circle of the shifting piece 10, so that the grooved wheel 11 cannot continue to rotate at a fixed angle position.

[0043] As the central shaft 3 continues to rotate 200°-300°, the large end 211 of the cam 21 contacts the roller 16 and slides into the groove 213 in the middle of the large end 211. During this process, the cam 21 pushes the moving contact system towards the stationary contact 4 until the moving contact 19 contacts the stationary contact 4. During this period, the moving contact 19 undergoes a alignment friction process on the stationary contact 4 after being subjected to force, clearing contact foreign objects (such as non-conductive carbonaceous matter, other non-conductive substances in the transformer oil, etc.) from the contact points of the stationary contact 4 and the moving contact 19. When the groove 213 of the cam 21 begins to contact the roller 16, due to the interaction between the groove 213 and the spring 20 (the spring 20 applies a pushing force towards the cam 21 to the contact support 16), the roller 16 automatically and completely engages with the groove 213 of the cam 21, forcing the central shaft 3 to automatically return to its original position, thus providing a strong tactile feedback when the switch is in position.

[0044] When the central shaft 3 rotates to 300°, gear 5 and cam 21 also rotate 300°, gear 6 and shifting part 10 rotate 360°, gear 6 and shifting part 10 return to the initial state, the large end 211 of cam 21 contacts roller 16 again, and the moving contact system is pushed to the maximum position by roller 16, forcing moving contact 19 to make tight contact with stationary contact 4. At this time, spring 20 has a large compression and returns to the initial state, the shifting ends, realizing easy shifting and strong feel when in position. Example 2

[0045] The difference between this embodiment and Embodiment 1 is that:

[0046] The transmission ratio between gear 5 and gear 6 is 7:8, and the corresponding number of stationary contacts is eight. Example 3

[0047] The difference between this embodiment and Embodiment 1 is that:

[0048] The transmission ratio between gear 5 and gear 6 is 9:10, and the corresponding number of stationary contacts is ten. Example 4

[0049] The difference between this embodiment and any one of embodiments 1-3 is that:

[0050] The unloaded, non-excitation drum-type tap changer with a tactile feel also includes a shielding cover 8, which is mounted on the upper mounting plate 1 and places the gear system in the middle. The shielding cover 8 is used to shield the electric field distribution at the tip of the gear system and improve the internal insulation performance of the switch. Example 5

[0051] The difference between this embodiment and any one of embodiments 1-3 is that:

[0052] The unloaded, non-excitation drum-type tap changer with a tactile feel also includes a gear position display device 25. The gear position display device 25 is disc-shaped and fixed on the central shaft 3, rotating synchronously with the central shaft 3. Gear position numbers are sprayed on the gear position display device 25 to indicate the gear position.

[0053] Other aspects of this invention that are not detailed herein are all conventional techniques known to those skilled in the art.

[0054] It should be noted that the terms “comprising,” “including,” or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0055] The scope of protection of this invention is not limited to the technical solutions disclosed in the specific embodiments. Any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of this invention shall fall within the scope of protection of this invention.

Claims

1. A drum-type tap changer with a tactile feel for unloading and shifting after the moving contact is engaged, comprising two mounting plates, a central shaft vertically mounted and rotatably mounted on both mounting plates, multiple stationary contacts vertically fixed between the two mounting plates and evenly distributed outside the central shaft, a gear system mounted on one of the mounting plates and rotating with the central shaft, a Geneva system rotatably mounted on the central shaft and rotating with the gear system, a moving contact bracket rigidly connected to the Geneva system and rotating with the Geneva system, and a moving contact system slidably mounted on the moving contact bracket and rotating with the moving contact bracket; wherein the moving contact system is used to connect any two adjacent stationary contacts, characterized in that, The tap changer also includes: A cam, corresponding to the moving contact system, is fixed on a central shaft and rotates synchronously with the central shaft. At each end of the cam are a large end that circumferentially contacts the moving contact system and a small end that does not. A groove is provided in the middle of the large end that engages with the moving contact system. During synchronous rotation with the central shaft, when the groove in the large end contacts and engages with the moving contact system, the cam pushes the moving contact system towards the stationary contact, pressing the moving contact system against two adjacent stationary contacts. A spring assembly, at least one of which includes a support member, a support ring, and a return spring. The support member is fixed to the moving contact system. The support ring is rotatably mounted on the central shaft. The return spring connects the support member and the support ring. The moving contact system includes a contact support, rollers, a pin, and a moving contact assembly. The contact support is slidably mounted on the moving contact support and can slide towards or away from the stationary contact. The contact support is C-shaped, with its open end facing the stationary contact and its closed end facing the central axis. The roller is rotatably mounted on the side of the closed end of the contact support facing the central axis via a vertically arranged pin, and the roller can mesh with the groove of the cam head. The pin is vertically fixed inside the open end of the contact support. The moving contact assembly includes multiple moving contacts stacked vertically and sleeved outside the pin. Each moving contact has an oblong hole with a length greater than the diameter of the pin along the sliding direction of the contact support. The moving contact can slide back and forth along the oblong hole and can connect two of the stationary contacts. A spring is connected between each moving contact and the inner wall of the closed end of the contact support.

2. The unloaded, de-energized drum-type tap changer with a tactile feel as described in claim 1, characterized in that: The number of rollers is two, and they are symmetrically arranged on the side of the closed end of the contact support facing the central axis.

3. The unloaded, de-energized drum-type tap changer with a tactile feel as described in claim 1, characterized in that: The number of spring assemblies is two, and they are symmetrically arranged between the contact support and the central shaft. The support of each spring assembly is fixed on the closed end of the contact support.

4. The unloaded, de-energized drum-type tap changer with a tactile feel as described in claim 1, characterized in that: The mounting plate includes an upper mounting plate and a lower mounting plate arranged horizontally; the stationary contact consists of multiple copper rod contacts evenly distributed on the same circumference outside the central shaft; the gear system includes gear one, a drive shaft, and gear two; gear one is fixed on the central shaft; the drive shaft is vertically and rotatably mounted on the upper mounting plate; gear two is fixed on the drive shaft and meshes with gear one; the grooved wheel system includes a grooved element and a grooved wheel, the grooved element is fixed on the drive shaft and rotates synchronously with gear two; the grooved wheel is rotatably mounted on the central shaft and can rotate under the action of the grooved element; the moving contact bracket includes an upper support, a lower support, and a connecting element, the upper support is fixedly connected to the grooved wheel and can rotate with the grooved wheel; the lower support is rotatably mounted on the central shaft; the connecting element is fixedly connected between the upper support and the lower support; symmetrical slides are provided at the bottom of the upper support and the top of the lower support; the upper and lower ends of the contact bracket are slidably mounted on the slides and slide along the slides between the stationary contact and the central shaft.

5. The unloaded, de-energized drum-type tap changer with a tactile feel as described in claim 4, characterized in that: The grooved wheel is an embedded grooved wheel with multiple circumferentially distributed locking grooves evenly provided on its inner side; the lower end of the corresponding chuck extends into the grooved wheel and has a locking circle on its lower side that can engage with the locking groove.

6. The unloaded, de-energized drum-type tap changer with a tactile feel as described in claim 4, characterized in that: The transmission ratio between gear one and gear two is n:(n+1), where n is a natural number greater than 2, and the number of stationary contacts is equal to n+1.

7. The unloaded, de-energized drum-type tap changer with a tactile feel as described in claim 1, characterized in that: When the moving contact disengages from the stationary contact, the distance from the center of the central shaft to the large end of the cam is greater than the distance from the center of the central shaft to the closed end of the contact support.

8. The de-energized drum-type tap changer with a tactile feel after unloading of the moving contact, as described in any one of claims 1-7, is characterized in that: It also includes a gear position display device, which is disc-shaped and fixed on a central axis, and rotates synchronously with the central axis. Gear position numbers for indicating the gear position are sprayed on the gear position display device.

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