CN220585081U - Small-sized non-excitation tapping switch - Google Patents

Abstract

The utility model provides a small non-excitation tapping switch, which comprises a manual operating mechanism for manually switching and indicating gears, a central insulating transmission shaft vertically arranged and in transmission connection with the manual operating mechanism, two supporting insulating strips vertically fixed at the bottom of the manual operating mechanism and positioned at two sides of the central insulating transmission shaft, and at least one contact system, wherein each contact system consists of a fixed contact assembly and a movable contact assembly; the fixed contact assembly is arranged below the manual operating mechanism and is semi-cylindrical, and comprises two insulating support plates which are parallel up and down and are semi-circular and a plurality of fixed contacts which are vertically arranged; the movable contact assembly comprises a metal base, a metal support piece and at least one movable contact group; the movable contact group is arranged between the two insulating support plates and comprises a movable contact conducting ring, an ejector rod and a spring. The utility model has simple structure, small volume, low manufacturing cost and stable and reliable performance.

Description

Small-sized non-excitation tapping switch

Technical Field

The utility model belongs to the technical field of non-excitation tapping switches, and particularly relates to a small non-excitation tapping switch for a transformer.

Background

The non-excitation tapping switch is mainly suitable for a power transformer, a distribution transformer and a traction transformer thereof which are subjected to non-excitation voltage regulation, and is also suitable for an industrial transformer which is subjected to non-excitation voltage regulation, in particular to a small-sized electric furnace transformer for smelting. For example, most of the power transformers for boosting, three-turn power transformers, and distribution transformers with significant changes in medium-voltage winding load and relatively stable line terminal voltage adopt a non-excitation voltage regulation mode.

The non-exciting tap switch in the market can be classified into a cage shape, a drum shape, a bar shape, a disc shape and the like according to the structure. The working current and the voltage of the cage-shaped and drum-shaped non-excitation tapping switch are relatively large, and the cage-shaped non-excitation tapping switch has large volume and small drum-shaped non-excitation tapping volume; the working voltage and the voltage of the bar-shaped non-excitation tapping switch are relatively low, the cost is relatively low, and the switch length is generally longer; the working voltage and current of the disk-shaped non-excitation tapping switch are relatively minimum, the cost is relatively minimum, the switch volume is also minimum, the working voltage is usually less than 12kv, and the working current is also less than 100A. The non-excitation voltage-regulating transformer with the working voltage of 12-35kv and the working current of more than 100A in the current market cannot meet the requirements for the working current and the working voltage of the disc-shaped non-excitation tap changer, the cage-shaped or bar-shaped non-excitation tap changer needs to be selected at more purchase cost, the transformer is larger in size, and the drum-shaped non-excitation tap changer needs to be selected at more purchase cost.

In order to save investment and avoid waste, it is necessary to develop a small-sized non-excited tap switch with small volume (occupying small space of the transformer), working current larger than 100A, working voltage 12-35kv and low production and manufacturing cost.

Disclosure of Invention

In order to solve the problems, the utility model aims to provide the small non-excited tap switch which has small volume, stable and reliable performance and low manufacturing cost, and fills the market blank of the non-excited tap switch which has small volume, working voltage of 12-35kv and working current of more than 100A and is lacking in the oil immersed transformer market.

The aim of the utility model is achieved by the following technical scheme:

a small-sized non-excitation tapping switch comprises a manual operating mechanism for manually switching and indicating gears, and a central insulating transmission shaft vertically arranged and in transmission connection with the manual operating mechanism; the method is characterized in that: the device also comprises two supporting insulating strips vertically fixed at the bottom of the manual operating mechanism and positioned at two sides of the central insulating transmission shaft, and at least one contact system, wherein each contact system consists of a fixed contact assembly and a movable contact assembly.

The fixed contact assembly is arranged below the manual operating mechanism and is semi-cylindrical, and comprises two insulating support plates which are parallel up and down and are semi-circular and a plurality of fixed contacts which are vertically arranged; the two ends of the insulating supporting plates are respectively fixed on two supporting insulating battens, and the two insulating supporting plates are movably sleeved outside the central insulating transmission shaft through holes preset in the centers of the two insulating supporting plates; the static contacts are uniformly distributed along the circular arcs of the insulating support plates, and the upper end and the lower end of each static contact are respectively fixed on the two insulating support plates.

The movable contact assembly comprises a metal base, a metal support piece and at least one movable contact group; the metal base is cylindrical and is sleeved and fixed outside the central insulating transmission shaft; the metal supporting piece is fixed on the side wall of the metal base and is positioned between the two insulating supporting plates; the movable contact group is arranged between the two insulating support plates and comprises a movable contact conducting ring, an ejector rod and a spring; the movable contact conducting ring is rotatably sleeved outside the metal support piece and positioned between the two insulating support plates; one end of the ejector rod is propped against the inner wall of the movable contact conducting ring, and the other end of the ejector rod is movably sleeved in a through hole preset in the metal support piece; the spring is sleeved outside the ejector rod, one end of the spring is in contact with the metal supporting piece, and the other end of the spring is in contact with a preset step on the ejector rod.

Further, the contact system is three semi-cylindrical bodies which are arranged on the same side below the manual operation mechanism from top to bottom, and each contact system corresponds to one phase of the power supply.

Further, the number of the static contacts is six and the static contacts are uniformly distributed along the semicircular arc of the insulating support plate, and two adjacent static contacts are communicated through the movable contact conducting rings of the movable contact group.

Further, the upper and lower ends of the metal base extend into the through holes of the two insulating support plates respectively and can rotate (relatively rotate) in the through holes.

Further, in order to make the relative rotation between the through hole and the metal base smoother; the metal base is respectively connected with the through holes of the two insulating support plates in a rotating way through bearings or shaft sleeves.

Furthermore, the number of the movable contact groups is two and the movable contact groups are vertically stacked between the two insulating support plates to achieve rated current 200A, and in addition, 3 movable contact conducting rings can be arranged to achieve rated current 300A. .

Further, in order to realize the limit of the ejector rod and prevent the ejector rod from deflecting up and down, the inner wall of the moving contact conducting ring is provided with an annular groove, and one end of the ejector rod is propped in the annular groove of the inner wall of the moving contact conducting ring and can slide along the concave annular groove.

Furthermore, in order to enable the ejector rod to slide smoothly along the groove, one end of the ejector rod, which is propped against the groove on the inner wall of the conductive ring of the moving contact, is a ball head.

Further, the manual operation mechanism comprises a flange plate, a central shaft, a lock catch and a handle; the flange plate is arranged above the contact system, the bottom of the flange plate is fixedly connected with the tops of the two supporting insulating strips, gear display numbers are cast in the area, which is positioned right above the contact system, of the upper surface of the flange plate, a lock sleeve is vertically arranged in the center of the top of the flange plate, a central hole penetrating through the flange plate is formed in the inner side of the lock sleeve, a plurality of lock grooves are uniformly formed in the outer side of the lock sleeve, and the lock grooves positioned on one side of the gear display numbers correspond to the gear display numbers one by one; the central shaft is sleeved in the central hole of the lock sleeve, the lower end of the central shaft extends below the flange plate and is coaxially connected with the central insulating transmission shaft, the upper end of the central shaft extends out of the upper central hole, and flat grooves penetrating through two sides of the central shaft are transversely formed in the upper end of the central shaft; the lock catch is arranged in the flat groove in a sliding way, both ends of the lock catch extend out of the flat groove, a lock nail corresponding to the position of the lock groove is fixed at the bottom of one end of the lock catch facing the gear display number, and after the lock nail slides to the lock sleeve along with the lock catch, the lock nail is clamped in the lock groove and points to the gear display number corresponding to the lock groove; the handle is fixedly connected to the top of the central shaft.

Further, in order to lock the manual operation mechanism, a lock hole is formed in one end, far away from the gear display number, of the lock catch, when the lock nail slides along with the lock catch and is clamped in the lock groove, the lock hole at the other end of the lock catch is exposed out of the flat groove, a bolt is arranged in the lock hole or the lock is used for locking the manual operation mechanism, and if a padlock is arranged in the lock hole, a key person can operate the manual operation mechanism.

The utility model has the beneficial effects that:

the non-excitation tapping switch has the advantages of simple structure, small volume, low manufacturing cost and stable and reliable performance; the low price can save the purchase cost for the manufacture of the transformer, the small volume of the non-excitation tapping switch can reduce the transformer box body and the use of transformer oil, and save the production cost for the manufacture of the transformer, thereby saving the resources for the investment of the power grid. The method fills the market blank of the non-excited tap switch which is lack of small volume, working voltage of 12-35kv and working current of more than 100A in the oil immersed transformer market, provides a new non-excited tap switch for the market, adds a choice for the design and manufacture of the transformer, and enriches the types of the non-excited tap switch for the transformer.

Drawings

The utility model is described in further detail below with reference to the accompanying drawings.

FIG. 1 is a front view of a compact off-circuit tap changer according to the utility model;

FIG. 2 is a cross-sectional view at A-A in FIG. 1;

FIG. 3 is a top view of the manual operating mechanism of the present utility model;

FIG. 4 is a cross-sectional view taken along the direction B-B in FIG. 3;

fig. 5 is a front view of the contact system of the present utility model;

FIG. 6 is a cross-sectional view taken along the direction C-C in FIG. 5;

FIG. 7 is a front view of the stationary contact assembly of the present utility model;

FIG. 8 is a cross-sectional view taken along the direction D-D in FIG. 7;

FIG. 9 is a right side view of the moving and static contact assembly of the present utility model;

FIG. 10 is a cross-sectional view taken along the direction E-E in FIG. 9;

the figure shows: 1-manual operating mechanism, 101-flange, 1011-gear display number, 1012-lock sleeve, 1013-lock groove, 102-central shaft, 103-lock catch, 1031-lock pin, 1032-lock hole, 104-handle, 2-central insulated transmission shaft, 3-supporting insulated slat, 4-static contact component, 401-insulated supporting plate, 402-static contact, 403-bearing or shaft sleeve, 5-moving contact component, 501-metal base, 502-metal support, 503-moving contact conducting ring, 5031-annular groove, 504-ejector pin, 5041-step, 505-spring.

Detailed Description

Further advantages and effects of the present utility model will become apparent to those skilled in the art from the disclosure of the present utility model, which is described by the following specific examples. The described embodiments are only some, but not all, embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

It should be understood that the structures, proportions, sizes, etc. shown in the drawings are for illustration purposes only and should not be construed as limiting the utility model to the extent that it can be practiced, since modifications, changes in the proportions, or adjustments of the sizes, which are otherwise, used in the practice of the utility model, are included in the spirit and scope of the utility model which is otherwise, without departing from the spirit or scope thereof. Also, the terms such as "upper", "lower", "left", "right", "middle", etc. are used herein for convenience of description, but are not to be construed as limiting the scope of the utility model, and the relative changes or modifications are not to be construed as essential to the scope of the utility model.

In the description of the present utility model, it should be noted that, unless explicitly specified and limited otherwise, the terms "connected," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

Example 1

As shown in fig. 1 and 2, the present embodiment provides a small-sized non-excited tap changer, including:

a manual operating mechanism 1, wherein the manual operating mechanism 1 is used for operating the off-circuit tap-changer to change the gear position and indicating the number of the tapping positions of the off-circuit tap-changer currently. As shown in fig. 3 and 4, the manual operation mechanism 1 includes a flange 101, a central shaft 102, a latch 103, and a handle 104; the flange plate 101 is arranged above the contact system (in a disc structure), the flange plate 101 adopts an aluminum casting, gear display numbers 1011 are cast on the upper surface of the flange plate 101 in the area right above the contact system, the gear display numbers 1011 are directly cast on the surface of the flange plate 101 as 1, 2, 3, 4 and 5, a commonly used stainless steel word plate or a sealing cavity is canceled to be provided with a circular indication plate, the cost of manufacturing parts is reduced, and the problem of incorrect installation of the indication plate is completely eradicated; a lock sleeve 1012 is vertically arranged in the center of the top of the flange plate 101, a central hole penetrating through the flange plate is formed in the inner side of the lock sleeve 1012, a plurality of lock grooves 1013 are uniformly formed in the outer side of the lock sleeve 1012, and the lock grooves 1013 positioned on one side of the gear display number 1011 are in one-to-one correspondence with the gear display number 1011; the central shaft 102 is rotatably sleeved in a central hole of the lock sleeve 1012, the lower end of the central shaft 102 extends below the flange plate 101 and is coaxially connected with the central insulating transmission shaft 2 (through an elastic pin), the upper end of the central shaft 102 extends out of an upward central hole, and flat grooves penetrating through two sides of the central shaft 102 are transversely formed in the upper end of the central shaft 102; the lock catch 103 is slidably arranged in the flat groove, both ends of the lock catch 103 extend out of the flat groove, the lock catch 103 is in a flat strip shape, a lock pin 1031 corresponding to the position of the lock groove 1013 is fixed at the bottom of one end of the lock catch 103 facing the gear display number 1011, when the lock pin 1031 slides towards the lock sleeve 1012 along with the lock catch 103, the lock pin 1031 is blocked in the lock groove 1013 (the central shaft 102 is prevented from rotating, the self-locking is realized) and points to the gear display number 1011 corresponding to the lock groove 1013, the lock catch 103 has the functions of self-locking an operating mechanism and gear indication, and the lock catch 103 points to the gear display number 1011 corresponding to the corresponding gear; the handle 104 is fixedly connected to the top of the central shaft 102 by a resilient pin.

The manual operating mechanism 1 is characterized in that a locking device is arranged and can lock a gear after gear shifting is finished; the second characteristic is that the gear display number 1011 cancels the traditional word board form, directly casts the gear display number 1011 on the corresponding position of the flange 101, the benefit is that the gear display number 1011 will not be stained, the word is clear, the word part is reduced, and the manufacturing expenditure is reduced.

A central insulated drive shaft 2, said central insulated drive shaft 2 being arranged vertically and being axially connected (rigidly connected) to a central shaft 102 of the manual operating mechanism 1. The movable contact assembly 5 is fixed on the central insulating transmission shaft 2 at the position corresponding to the fixed contact assembly 4 through a notch and a pin hole, and the movable contact assembly 5 is driven to rotate.

The number of the supporting insulating strips 3 is two, and the two supporting insulating strips 3 are vertically fixed at the bottom of the flange plate 101 of the manual operation mechanism 1 through screws and are positioned at two sides of the central insulating transmission shaft 2.

As shown in fig. 1, the contact systems are three semi-cylindrical bodies which are arranged on the same side below the manual operation mechanism 1 from top to bottom (right below the side of the flange plate 101 provided with the gear display number 1011), and each contact system corresponds to one phase of a power supply. As shown in fig. 5 and 6, each contact system is composed of a fixed contact assembly 4 and a movable contact assembly 5.

As shown in fig. 7 and 8, the fixed contact assembly 4 is disposed below the manual operating mechanism 1 (directly below the side of the flange 101 with the gear display number 1011), and is in a semi-cylindrical shape as a whole, and the fixed contact assembly 4 includes two insulating support plates 401 disposed in parallel up and down and in a semi-circular shape and six fixed contacts 402 disposed vertically; the two insulating support plates 401 are movably sleeved outside the central insulating transmission shaft 2 through holes preset in the centers of the two insulating support plates 401, two metal connecting blocks are respectively arranged on two sides of the insulating support plates 401, the metal connecting blocks are clamped between the two insulating support plates 401 and fixedly connected with the two insulating support plates 401 through pins, and meanwhile the two metal connecting blocks are respectively fixed on the two supporting insulating strips 3 at preset positions through screws, so that the static contact assembly 4 is fixed. The fixed contacts 402 are columnar and uniformly distributed along the semicircular arcs of the insulating support plates 401, and the upper end and the lower end of each fixed contact 402 are respectively fixed on the two insulating support plates 401. The two ends of the fixed contact 402 are provided with threads and are respectively fixed on the two insulating support plates 401 through nuts, one end of the fixed contact 402 is provided with long threads, and the long threads are used for supplying the transformer factory connection coil lead wires to be electrically connected with the connection coil lead wires.

As shown in fig. 9 and 10, the moving contact assembly 5 includes a metal base 501, a metal support 502, and two moving contact groups; the metal base 501 is cylindrical, and the inner side of the metal base 501 is sleeved and fixed outside the central insulating transmission shaft 2 through a pin, and the upper and lower ends of the metal base 501 respectively extend into the through holes of the two insulating support plates 401 and can rotate (relatively rotate) in the through holes; in order to make the relative rotation between the through holes and the metal base 501 smoother, the through holes of the metal base 501 and the two insulating support plates 401 are respectively connected in a rotating way through bearings or shaft sleeves; the metal supporting piece 502 is fixed on the side wall of the metal base 501 and is positioned between the two insulating supporting plates 401, the metal supporting piece 502 is integrally C-shaped, and the opening end of the metal supporting piece faces the metal base 501 and is fixedly connected with the metal base 501; the number of the movable contact groups is two and the movable contact groups are stacked between the two insulating support plates 401 up and down to realize rated current 200A, and each movable contact group comprises a movable contact conducting ring 503, an ejector rod 504 and a spring 505; the moving contact conducting ring 503 is a circular rolling conducting ring, the moving contact conducting ring 503 is rotatably sleeved outside the metal supporting member 502 and is located between the two insulating supporting plates 401, in order to limit the ejector rod 504 and prevent it from being deflected up and down, an annular groove 5031 is provided on the inner wall of the moving contact conducting ring 503; one end of the ejector rod 504 is a ball head, the ball head end of the ejector rod 504 is propped in the annular groove 5031 on the inner wall of the movable contact conductive ring 503 and can slide along the annular groove 5031, and the other end of the ejector rod 504 is movably sleeved in a preset through hole of the metal support piece 502 (closed end); the spring 505 is sleeved outside the ejector rod 504, one end of the spring 505 is in contact with the metal support 502 (propped against the closed end of the metal support 502), the other end of the spring 505 is in contact with a preset step 5041 on the ejector rod 504 (i.e. is positioned between the step 5041 and the closed end of the metal support 502), and the moving contact conducting ring 503 is propped against two adjacent fixed contacts 402 of the fixed contact assembly through the spring 505 and the ejector rod 504 to conduct the two adjacent fixed contacts 402.

The working principle is as follows:

during gear shifting, as shown in fig. 4, the lock catch 103 is slid, the lock pin 1031 of the lock catch 103 is disengaged from the lock groove 1013 outside the lock sleeve 1012, the central shaft 102 of the manual operation mechanism 1 is unlocked, the central shaft 102 is turned into a rotatable state, the handle 104 is turned, the central shaft 102 and the lock catch 103 are driven to synchronously rotate, after a certain angle of rotation, the lock catch 103 is aligned with the gear display number 1011 of a designated gear on the flange 101, which indicates that the designated gear is reached, then the lock catch 103 is slid reversely, the lock pin 1031 of the lock catch 103 is engaged with the lock groove 1013 outside the lock sleeve 1012 again, the central shaft 102 is locked, the central shaft 102 is prevented from rotating, in the gear shifting process, the operation process of the contact system is that the central shaft 102 rotates and simultaneously drives the central insulating transmission shaft 2 to synchronously rotate, the central insulating transmission shaft 2 drives the metal base 501, the metal support 502, the movable contact conducting ring 503 and the ejector rod 504 rotates while the movable contact conducting ring 503 to compress the compression ejector rod spring 505, after the movable contact conducting ring 503 rotates, the movable contact conducting ring 503 rotates to reach the next gear position, the spring 505 is pressed by the ejector rod 504, and the movable contact conducting ring 503 rotates to the next gear position after the highest point of the movable contact conducting ring 503, and the next two adjacent movable contact conducting ring 402 is pressed.

The small non-excited tap changer according to this embodiment is characterized in that the overall shape (except for the flange 101) is configured in a semi-cylindrical shape, and the whole non-excited tap changer is generally designed in a cylindrical shape. According to the design characteristics of the non-excited tap switch, the number of tap positions is 5, the current is 200-300A, the voltage level is 12-35kV, and circular arrangement is not needed at all, so that the overall dimension of the non-excited tap switch can be reduced, the waste of materials is reduced, the space of a transformer box body can be saved for a transformer installation test, and the use of transformer oil is reduced, thereby saving the production and manufacturing cost of the non-excited tap switch and the transformer thereof.

Example 2

This embodiment differs from embodiment 1 in that:

the number of the movable contact groups can be three and the movable contact groups are stacked between two insulating support plates 401, namely, 3 movable contact conducting rings 503 are arranged, so that rated current 300A is realized.

Example 3

This embodiment differs from embodiment 1 in that:

in order to further lock the manual operation mechanism 1, a lock hole 1032 is provided at one end of the lock catch 103 far away from the gear display number 1011, when the lock pin 1031 slides along with the lock catch 103 and is clamped in the lock slot 1013, the lock hole 1032 at the other end of the lock catch 103 exposes out of the flat slot, and the handle 104 can be locked by padlock in the lock hole 1032, so that the manual operation mechanism 1 can be operated by a person with a key, the unauthorized person can be prevented from operating the non-excited tap changer, and the operation safety of the equipment can be ensured.

Other aspects of the utility model are not specifically described and are well known to those skilled in the art.

It should be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

The protection scope of the present utility model is not limited to the technical solutions disclosed in the specific embodiments, and any modification, equivalent replacement, improvement, etc. made to the above embodiments according to the technical substance of the present utility model falls within the protection scope of the present utility model.

Claims (10)

1. A small-sized non-excitation tapping switch comprises a manual operating mechanism for manually switching and indicating gears, and a central insulating transmission shaft vertically arranged and in transmission connection with the manual operating mechanism; the method is characterized in that: the device also comprises two supporting insulating strips vertically fixed at the bottom of the manual operating mechanism and positioned at two sides of the central insulating transmission shaft, and at least one contact system, wherein each contact system consists of a fixed contact assembly and a movable contact assembly;

the fixed contact assembly is arranged below the manual operating mechanism and is semi-cylindrical, and comprises two insulating support plates which are parallel up and down and are semi-circular and a plurality of fixed contacts which are vertically arranged; the two ends of the insulating supporting plates are respectively fixed on two supporting insulating battens, and the two insulating supporting plates are movably sleeved outside the central insulating transmission shaft through holes preset in the centers of the two insulating supporting plates; the fixed contacts are uniformly distributed along the circular arcs of the insulating support plates, and the upper end and the lower end of each fixed contact are respectively fixed on the two insulating support plates;

the movable contact assembly comprises a metal base, a metal support piece and at least one movable contact group; the metal base is cylindrical and is sleeved and fixed outside the central insulating transmission shaft; the metal supporting piece is fixed on the side wall of the metal base and is positioned between the two insulating supporting plates; the movable contact group is arranged between the two insulating support plates and comprises a movable contact conducting ring, an ejector rod and a spring; the movable contact conducting ring is rotatably sleeved outside the metal support piece and positioned between the two insulating support plates; one end of the ejector rod is propped against the inner wall of the movable contact conducting ring, and the other end of the ejector rod is movably sleeved in a through hole preset in the metal support piece; the spring is sleeved outside the ejector rod, one end of the spring is in contact with the metal supporting piece, and the other end of the spring is in contact with a preset step on the ejector rod.

2. The miniature off-circuit tap-changer of claim 1, wherein: the contact system is three semi-cylindrical bodies which are arranged on the same side below the manual operating mechanism from top to bottom.

3. The miniature off-circuit tap-changer of claim 1, wherein: the number of the static contacts is six and the static contacts are uniformly distributed along the semicircular arc of the insulating support plate.

4. The miniature off-circuit tap-changer of claim 1, wherein: the upper end and the lower end of the metal base extend into the through holes of the two insulating support plates respectively and can rotate in the through holes.

5. The miniature off-circuit tap-changer of claim 4, wherein: the metal base is respectively connected with the through holes of the two insulating support plates in a rotating way through bearings or shaft sleeves.

6. The miniature off-circuit tap-changer of claim 1, wherein: the number of the movable contact groups is two and the movable contact groups are stacked between the two insulating support plates.

7. The miniature off-circuit tap-changer of claim 1, wherein: the inner wall of the movable contact conducting ring is provided with an annular groove, and one end of the ejector rod is propped in the annular groove on the inner wall of the movable contact conducting ring and can slide along the annular groove.

8. The miniature off-circuit tap-changer of claim 7, wherein: and one end of the ejector rod, which is propped against the inner wall groove of the movable contact conducting ring, is a ball head.

9. A compact non-excited tap changer according to any one of claims 1-8, wherein: the manual operation mechanism comprises a flange plate, a central shaft, a lock catch and a handle; the flange plate is arranged above the contact system, the bottom of the flange plate is fixedly connected with the tops of the two supporting insulating strips, gear display numbers are cast in the area, which is positioned right above the contact system, of the upper surface of the flange plate, a lock sleeve is vertically arranged in the center of the top of the flange plate, a central hole penetrating through the flange plate is formed in the inner side of the lock sleeve, a plurality of lock grooves are uniformly formed in the outer side of the lock sleeve, and the lock grooves positioned on one side of the gear display numbers correspond to the gear display numbers one by one; the central shaft is sleeved in the central hole of the lock sleeve, the lower end of the central shaft extends below the flange plate and is coaxially connected with the central insulating transmission shaft, the upper end of the central shaft extends out of the upper central hole, and flat grooves penetrating through two sides of the central shaft are transversely formed in the upper end of the central shaft; the lock catch is arranged in the flat groove in a sliding way, both ends of the lock catch extend out of the flat groove, a lock nail corresponding to the position of the lock groove is fixed at the bottom of one end of the lock catch facing the gear display number, and after the lock nail slides to the lock sleeve along with the lock catch, the lock nail is clamped in the lock groove and points to the gear display number corresponding to the lock groove; the handle is fixedly connected to the top of the central shaft.

10. The miniature off-circuit tap-changer of claim 9, wherein: the lock catch is provided with a lock hole at one end far away from the gear display number, and when the lock nail slides along with the lock catch and is clamped in the lock groove, the lock hole at the other end of the lock catch is exposed out of the flat groove, and a bolt or a lock is arranged at the lock hole to lock the manual operation mechanism.