Disconnector or earth switch

Abstract

To provide an operation mechanism for activating a disconnector or an earthing switch.SOLUTION: A disconnector or an earthing switch for connecting three conductors of different phases to respective switching tubes comprises: a rotatable drive shaft configured for operating the disconnector or the earthing switch; the three respective switching tubes, which are arranged and configured to be axially movable together between a connected position configured for connecting the three conductors and a disconnected position configured for not connecting the three conductors; a partially toothed worm wheel configured for translating a rotation of a worm into the axial movement of the three switching tubes between the connected position and the disconnected position, where the partially toothed worm wheel is disengaged from the worm in the connected position and the disconnected position; and a re-engagement device configured for engaging the partially toothed worm wheel again with the worm in the connected position and the disconnected position.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] statement Technical Field The present invention relates to a disconnector or earth switch for connecting three conductors of different phases to respective diverter tubes, the disconnector or earth switch comprising a rotatable drive shaft having a worm and configured to operate the earth switch and three respective diverter tubes, the three respective diverter tubes being arranged to be axially movable together between a connecting position configured to connect the three conductors and a disconnecting position configured to not connect the three conductors. [Background technology]

[0002] Background technology A disconnector or earthing switch, also known as a grounding switch, is a protective device included in switchgear components such as circuit breakers and isolators. When a circuit breaker is removed and racked out, the earthing switch automatically grounds a portion of the busbar adjacent to the circuit breaker. In the case of an isolator, the earthing switch contacts the busbar when the isolator separates the circuit, discharging any charge that may have collected there. For example, earthing switches in switchgear are used to ground the remaining changes in a power line after the line has been disconnected from its source. Residual charge often remains in a circuit after it has been disconnected or opened by circuit breakers and isolators. An earthing switch is usually provided to discharge the charge.

[0003] Disconnectors or earthing switches often have a snap-action closing mechanism to protect engineers and staff in the event of an abnormal current. Generally, disconnectors or earthing switches are designed to withstand short circuits. Disconnectors or earthing switches in substations have the ability to create a short circuit to protect other electrical equipment from damage. Disconnectors or earthing switches are often used with some high-voltage switchgear and also serve as protective devices during overhauls of high-voltage electrical equipment.

[0004] Such disconnectors or earth switches can be electrically operated or manually operated. If the drive of the disconnector or earth switch is operated by a motor, end switches must be present to limit the traverse of the operating mechanism actuated by the motor. During manual operation, defined end positions must be defined. However, prior art solutions unfortunately do not provide a sufficiently safe and easy operating mechanism for operating such disconnectors or earth switches. Summary of the Invention [Problem to be solved by the invention]

[0005] Summary of the Invention SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an improved operating mechanism for operating a disconnector or earth switch. [Means for solving the problem]

[0006] The object of the invention is achieved by the features of the independent claims. Preferred embodiments are detailed in the dependent claims.

[0007] The object is therefore to provide a particularly high voltage disconnector or earthing switch for connecting three conductors of different phases to respective switching tubes, a rotatable drive shaft having a worm and configured to operate a disconnector or earth switch; three respective switching tubes configured to be axially movable together between a connecting position configured to connect the three conductors and a disconnecting position configured to not connect the three conductors; a partially toothed worm wheel configured to convert rotation of the worm into axial movement of the three switching pipes between a connecting position and a disconnecting position, the partially toothed worm wheel being disengaged from the worm at the connecting position and the disconnecting position; and a re-engagement device configured to re-engage the partially toothed worm wheel with the worm, in particular in the connected and disconnected positions.

[0008] The proposed solution thus constitutes a kind of position-controlled freewheel that acts in the direction of rotation of the partially toothed worm wheel. A voltage disconnector or earth switch allows for the transmission of high torques while simultaneously providing the above-mentioned freewheel function in a very small installation space. The proposed freewheel function is thus based on the principle of geometrically controlled decoupling of the two gear partners, i.e., the partially toothed worm wheel and the rotatable drive shaft. Therefore, torque and rotational movement are transmitted only within a defined range of movement between the rotatable drive shaft and the partially toothed worm wheel.

[0009] In contrast to freewheels known from the prior art, whose function is based on friction between bodies, the proposed freewheel operates purely kinematically. Therefore, environmental factors and the deterioration of lubricants over time do not affect the function of the freewheel. The proposed freewheel, consisting of a rotatable drive shaft and a partially toothed worm wheel, can be used as a safety device to protect the motor drive mechanism in end positions in addition to an electrical stop device, such as a limit switch, and as a safety device to mechanically precisely decouple the input and output sides without being affected by the motor's coasting behavior.

[0010] Additionally, when the mechanism for connecting the three conductors of different phases to the respective switching tubes is manually operated by an operator, the proposed freewheel can be used to prevent over-operation. Thus, the operator cannot move the rotatable drive shaft further than the freewheel allows. The operator receives audible feedback that the freewheel has been reached from the sound emitted when the tooth flanks meet.

[0011] The term high voltage preferably refers to a voltage ranging from 36 to 1,100 kV. High voltage preferably relates to a nominal voltage in the range of more than 72 kV to 550 kV, for example 145 kV, 245 kV or 420 kV or even higher. The nominal current of the disconnector or earth switch may be in the range of 1 kA to 5 kA, or even higher, for example 80 kA instantaneously. The conductor may be part of a grid for distributing said high voltage.

[0012] The rotatable drive shaft is preferably supported by two bearings, between which the worm is mounted on the drive shaft. The bearings can be attached to the housing of the disconnector or earth switch. One end of the rotatable drive shaft is preferably configured to connect to a motor or a handwheel for rotating the drive shaft to operate the disconnector or earth switch. The three switching tubes can be provided as rods and / or can extend parallel to the rotatable drive shaft. A partially toothed worm wheel is preferably arranged on the output shaft, with its axis extending perpendicular to the drive shaft. The output shaft can be attached to the housing via another bearing. Partially toothed preferably means that at least a portion of the circumference of the worm wheel is free of teeth, and the remaining portion is provided with teeth corresponding to the worm. The toothless portion is not engaged with the worm. The worm can be provided as an external thread.

[0013] Therefore, when each of the three switching tubes approaches the connecting or disconnecting position, the teeth of the partially toothed worm wheel are no longer engaged with the worm. Because the partially toothed worm wheel is not engaged with the worm in the connecting or disconnecting position, any continued rotation of the drive shaft does not result in rotation of the partially toothed worm wheel with any movement of each of the three switching tubes. However, for example, if the drive shaft stops rotating and is rotated in the opposite direction, the re-engagement device ensures that the partially toothed worm wheel re-engages with the worm.

[0014] Thus, there is no contradiction between the statement that the partially toothed worm wheel is not engaged with the worm at the connection and disconnection positions and the statement that the re-engagement device re-engages the partially toothed worm wheel with the worm at the connection and disconnection positions. The re-engagement device is preferably triggered by the connection and disconnection positions and / or when the connection and disconnection positions are reached to re-engage the partially toothed worm wheel with the worm.

[0015] According to preferred embodiments, the teeth of the partially toothed worm wheel extend over approximately 180° or less, 160° or less, 140° or less, 120° or less, or 100° or less. Preferably, therefore, no teeth are provided over more than 180°, 200°, >220°, 240°, or 260° of the partially toothed worm wheel. The partially toothed worm wheel preferably has a disk-like form, whereby the teeth are arranged around the radial circumference. The teeth and the worm may have any suitable form that allows them to mate with each other.

[0016] In another preferred embodiment, the partially toothed worm wheel is provided as a pitch circular disk having opposing end faces for engaging with the re-engagement device. The pitch circular disk may have the form of a pie piece with teeth arranged along its periphery, i.e., on the piece. The remaining portion, i.e., the portion where no pie piece is present, may be hollow. The end faces preferably extend axially and radially relative to the output shaft as the axis of the partially toothed worm wheel. The worm wheel is preferably rigidly connected to the output shaft. The end faces preferably engage with the re-engagement device in the engagement and disengagement positions to respectively trigger the re-engagement device to re-engage the partially toothed worm wheel with the worm.

[0017] According to another preferred embodiment, the re-engagement device is configured to be rechargeable by the partially toothed worm wheel reaching the connected or disconnected position in order to re-engage the partially toothed worm wheel with the worm. Charging the re-engagement device means, for example, that a force is generated in the re-engagement device that subsequently allows the partially toothed worm wheel to be re-engaged with the worm.

[0018] In another preferred embodiment, the re-engagement device is provided as a torsion spring and / or a compression spring configured to apply a spring force to the partially toothed worm wheel and / or a repulsive magnet pair configured to apply a repulsive magnetic force to the partially toothed worm wheel. The torsion spring can be housed in a torsion spring housing and can have two torsion spring legs, one for engaging the worm wheel with the worm in the connect position and the other for engaging the worm wheel with the worm in the disconnect position.

[0019] According to another preferred embodiment, the disconnector or earth switch includes a contact support that holds the three switching tubes apart and / or a guide configured to guide the axial movement of each switching tube. The contact support preferably extends parallel to the output shaft and / or perpendicular to the switching tubes and / or the rotatable drive shaft. The contact support may have a three-sided triangular shape with one switching tube disposed on each side. The guide may be provided as a sliding contact for guiding and / or providing an electrical connection to each switching tube.

[0020] In another preferred embodiment, the disconnector or earth switch comprises a fork bolt connection configured to convert rotation of the partially toothed worm wheel into axial movement of the three diverter pipes. Preferably, the fork is rigidly connected to the output shaft, while the fork can be rigidly connected to another diverter pipe and / or to a rod that is stationarily connected in parallel to the three diverter pipes. Preferably, the diverter pipes are connected to the partially toothed worm wheel by two oppositely arranged bolts and two oppositely arranged forks.

[0021] According to another preferred embodiment, each switching tube comprises a contact pin adapted to connect to a contact tulip of a respective conductor, the contact pins preferably being arranged at a distance from one another.

[0022] In another preferred embodiment, the three switching tubes are connected to ground. In this manner, the three switching tubes may be connected together and / or have a common connector. Alternatively, the three switching tubes may each be connected to a separate conductor.

[0023] According to another preferred embodiment, the disconnector or earthing switch is provided as a fast-acting earthing switch, a proof earthing switch or a disconnector earthing switch, whereby the proposed solution allows the respective fast-acting earthing switch, a proof earthing switch or a disconnector earthing switch to be installed in a very small installation space.

[0024] The object is to use a partially toothed worm wheel to connect three conductors of different phases to respective switching tubes, the partially toothed worm wheel being: a rotatable drive shaft having a worm and configured to operate the earth switch; three respective switching tubes configured to be axially movable together between a connecting position configured to connect the three conductors and a disconnecting position configured to not connect the three conductors; a partially toothed worm wheel configured to convert rotation of the worm into axial movement of the three switching pipes between a connecting position and a disconnecting position, the partially toothed worm wheel being disengaged from the worm at the connecting position and the disconnecting position; The solution is further achieved by the use of a partially toothed worm wheel with a re-engagement device configured to re-engage the partially toothed worm wheel with the worm, in particular in the connection and disconnection positions.

[0025] Further embodiments and advantages of this use are directly and clearly derivable by a person skilled in the art from the disconnector or earth switch described above.

[0026] BRIEF DESCRIPTION OF THE DRAWINGS These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a perspective view of a disconnector or earth switch for connecting three conductors of different phases to respective switching tubes according to a preferred embodiment. [Figure 2] 2 is a perspective view of a rotatable drive shaft and a partially toothed worm wheel of the disconnector or earth switch according to FIG. 1, according to a preferred embodiment. FIG. [Figure 3] 2 is a side view of the rotatable drive shaft and partially toothed worm wheel of the disconnector or earth switch according to FIG. 1 fully engaged, according to a preferred embodiment; FIG. [Figure 4] 2 is a side view of a rotatable drive shaft and partially toothed worm wheel of the disconnector or earth switch according to FIG. 1, partially engaged, according to a preferred embodiment; FIG. [Figure 5] 2 is a side view of the rotatable drive shaft and partially toothed worm wheel of the disconnector or earth switch according to FIG. 1 in disengagement, according to a preferred embodiment; FIG. [Figure 6] 2 is a side view of the rotatable drive shaft and partially toothed worm wheel of the disconnector or earth switch according to FIG. 1 re-engaging, according to a preferred embodiment; FIG. [Figure 7] 2 is a side view of a rotatable drive shaft and a partially toothed worm wheel of the disconnector or earth switch according to FIG. 1 according to another preferred embodiment. [Figure 8] 2 is a side view of a rotatable drive shaft and a partially toothed worm wheel of a circuit breaker or earth switch according to FIG. 1 according to yet another preferred embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0028] Description of the Preferred Embodiments 1 shows in perspective view a disconnector or earth switch 1 for connecting three conductors 2 of different phases to respective switching tubes 3 according to a preferred embodiment. The three conductors 2 are part of the grid and therefore each carry a high voltage in the range of 36-800 kV. The disconnector or earth switch 1 comprises a rotatable drive shaft 4, three respective switching tubes 3, a partially toothed worm wheel 5, and a re-engagement device 6.

[0029] The rotatable drive shaft 4 is equipped with a worm 7 rigidly connected to the rotatable drive shaft 4. The rotatable drive shaft 4 is held by two bearings 8 in a housing (not shown) of the disconnector or earth switch 1. The worm 7 is arranged between the two bearings 8. One end 9 of the rotatable drive shaft 4 is arranged to be operated by a motor or handle (not shown) for operating the disconnector or earth switch 1.

[0030] The three switching tubes 3 are held by a contact carrier 10 which runs parallel to the rotatable drive shaft 4 and has the shape of a triangle with one switching tube 3 on each side. The three switching tubes 3 are thus joined by the contact carrier 10 and held by guides 11 which are provided as sliding contacts in the housing. All three guides 11 are connected to earth as shown in the diagram of the earth switch 1. In the case of a disconnector, the three guides 11 can be connected to other conductors.

[0031] The three guides 11 enable the three switching tubes 3 to be moved axially together between a connection position, not shown in Fig. 1, in which each switching tube 3 is electrically connected to a respective conductor 2, and a disconnection position, shown in Fig. 1, in which each switching tube 3 is electrically disconnected from a respective conductor 2. Thus, each tip of the three switching tubes 3 is provided with a contact pin 12, and each tip of the three conductors 2 is provided with a corresponding contact tulip 13.

[0032] To move the three diverter pipes 3 axially, the worm 7 engages with teeth 14 of a partially toothed worm wheel 5, as shown in more detail in Figure 2. The partially toothed worm wheel 5 comprises an output shaft 15, which is held by the housing via another bearing 8. In this way, the output shaft 15 extends perpendicular to the rotatable drive shaft 4.

[0033] Rigidly connected to the output shaft 15 is a fork bolt connection 16, which connects the output shaft 15 to a rod 17 that is fixedly connected in parallel to the three diverter pipes 3 to the contact support 10. Two oppositely arranged bolts extend from the rod 17 and are contained in two oppositely arranged respective forks connected to the output shaft 15. In this way, rotation of the rotatable drive shaft 4 is translated into axial movement of the three diverter pipes 3 for moving the three diverter pipes 3 between their connected and disconnected positions.

[0034] Reference is now made to Figures 2 to 6 which show the rotatable drive shaft 4 and partially toothed worm wheel 5 of the disconnector or earth switch 1 according to Figure 1 according to a preferred embodiment. Figures 2 and 3 show the rotatable drive shaft 4 and partially toothed worm wheel 5 fully engaged, i.e. the teeth of the worm 7 are engaged with the teeth 14 of the partially toothed worm wheel 5.

[0035] The teeth 14 extend over 120° of the circumference of the partially toothed worm wheel 5, which is thus presented as a pitch circular disc, i.e. a piece of a cake extending over approximately 120°. The pitch circular disc has at its ends two oppositely arranged end faces 20 which extend axially and radially relative to the output shaft 15. In Figures 2 and 3, the end faces 20 are not engaged with the re-engagement device 6.

[0036] FIG. 4 is a side view of the rotatable drive shaft 4 and partially toothed worm wheel 5 of the disconnector or earth switch 1 according to FIG. 1 in a partially engaged state according to a preferred embodiment, approaching the disconnect position in a counterclockwise direction.

[0037] The re-engagement device 6 is provided as a torsion spring having two spring legs 19 extending from a torsion spring housing 18 of the re-engagement device 6 which is mounted on the housing of the disconnector or earth switch 1, as can be seen particularly in Figure 2. As the disconnect position is approached, one spring leg engages one end face 20, thereby causing each torsion spring to apply a spring force to the re-engagement device 6.

[0038] 5 shows the rotatable drive shaft 4 and partially toothed worm wheel 5 or worm 7 and teeth 14 fully disengaged in the disconnected position, while the torsion spring or re-engagement device 6 is fully loaded with spring force. The spring force is directed in a clockwise direction, opposite to the previous direction of rotation of the partially toothed worm wheel 5. Furthermore, any further rotation of the rotatable drive shaft 4 no longer results in axial movement of the three diverter tubes 3.

[0039] The spring force acting on one end face 20 then presses the outermost tooth flank of the partially toothed worm wheel 5 against the tooth flank of the last tooth of the worm 7, as can be seen in Figure 6. Thus, when the partially toothed worm wheel 5 moves in the intended clockwise direction, the re-engagement device 6 makes it possible to re-engage the partially toothed worm wheel 5 with the worm 7 in the disengaged position. The proposed solution makes it possible to restore the engagement between the partially toothed worm wheel 5 and the worm 7 in the disengaged position and in the connected position, not shown.

[0040] Figures 7 and 8 show in side view the rotatable drive shaft 4 and the partially toothed worm wheel 5 of the disconnector or earth switch 1 according to Figure 1 according to two further preferred embodiments. In Figure 7 the re-engagement device 6 is provided as a compression spring configured to apply a spring force to the partially toothed worm wheel 5, and in Figure 8 the re-engagement device 6 is provided as a repulsive magnet pair configured to apply a repulsive magnetic force to the partially toothed worm wheel 5.

[0041] While the invention has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive, and the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims are not to be construed as limiting the scope. [Explanation of symbols]

[0042] List of Reference Numbers 1. Disconnector or earth switch 2 conductors 3 Switching pipe 4 rotatable drive shafts 5 Partially toothed worm wheel 6 Re-engaging device 7. Warm 8 bearings 9 End 10 Contact support 11 Information Department 12 contact pins 13 Contact Tulip 14 teeth 15 Output shaft 16 Fork bolt connection 17 Rod 18 Torsion spring housing 19 Spring legs 20 End face

Claims

1. A disconnector or earth switch (1) for connecting three conductors (2) of different phases to respective switching tubes (3), a rotatable drive shaft (4) provided with a worm (7) and configured to operate said disconnector or earth switch (1); the three respective switching tubes (3) being arranged to be movable together in an axial direction between a connection position configured to connect the three conductors (2) and a disconnection position configured to not connect the three conductors (2); a partially toothed worm wheel (5) configured to convert rotation of the worm (7) into axial movement of each of the three switching pipes (3) between the connection position and the disconnection position, the partially toothed worm wheel (5) being disengaged from the worm (7) at the connection position and the disconnection position; a re-engagement device (6) configured to re-engage the partially toothed worm wheel (5) with the worm (7) in the connection position and the disconnection position, The disconnector or earth switch (1), wherein the partially toothed worm wheel (5) is provided as a pitch circular disc having opposite end faces (20) for engagement with the re-engagement device (6).

2. 2. The circuit breaker or earth switch (1) according to claim 1, wherein the teeth (14) of the partially toothed worm wheel (5) extend through an angle of less than 180°.

3. 3. The circuit breaker or earth switch (1) according to claim 1 or 2, wherein the re-engagement device (6) is configured to be rechargeable by the partially toothed worm wheel (5) reaching the connection position or the disconnection position in order to re-engage the partially toothed worm wheel (5) with the worm (7).

4. 3. The circuit breaker or earth switch (1) according to claim 1 or 2, wherein the re-engagement device (6) is provided as a torsion spring and / or a compression spring configured to apply a spring force to the partially toothed worm wheel (5) and / or as a repulsive magnet pair configured to apply a repulsive magnetic force to the partially toothed worm wheel (5).

5. 3. The disconnector or earth switch (1) according to claim 1 or 2, comprising a contact support (10) that holds the three respective switching pipes (3) apart from one another, and / or a guide portion (11) configured to guide the axial movement of the respective switching pipes (3).

6. 3. The circuit breaker or earth switch (1) according to claim 1 or 2, comprising a fork bolt connection (16) configured to convert rotation of the partially toothed worm wheel (5) into the axial movement of the three respective switching pipes (3).

7. 2. The disconnector or earth switch (1) according to claim 1, wherein each switching tube (3) comprises a contact pin (12) configured to connect the contact tulips (13) of the respective three conductors (2).

8. 3. The disconnector or earth switch (1) according to claim 1 or 2, wherein the three respective switching pipes (3) are connected to earth.

9. 3. The disconnector or earthing switch (1) according to claim 1 or 2, wherein the disconnector or earthing switch (1) is provided as a fast acting earthing switch, a proof earthing switch or a disconnector earthing switch.

10. Use of a partially toothed worm wheel (5) for connecting three conductors (2) of different phases to respective switching tubes (3), a rotatable drive shaft (4) provided with a worm (7) and configured to operate a disconnector or earth switch (1); the three respective switching tubes (3) being arranged to be movable together in an axial direction between a connection position configured to connect the three conductors (2) and a disconnection position configured to not connect the three conductors (2); a partially toothed worm wheel (5) configured to convert rotation of the worm (7) into axial movement of each of the three switching pipes (3) between the connection position and the disconnection position, the partially toothed worm wheel (5) being disengaged from the worm (7) at the connection position and the disconnection position; a re-engagement device (6) configured to re-engage the partially toothed worm wheel (5) with the worm (7) in the connection position and the disconnection position, Use of a partially toothed worm wheel (5), wherein said partially toothed worm wheel (5) is provided as a pitch circular disc having opposite end faces (20) for engagement with said re-engagement device (6).

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