Static contact unit, contact system and tap changer

Abstract

A stationary contact unit (20) for a tap changer includes a contact body (4), one or more contact elements, and a spring element. The contact body (4) is configured to be stationary relative to a movable contact on a moving shaft (1) of the tap changer. At least one contact element (5) is pivotally coupled to the contact body (4) and configured to establish electrical contact with a movable contact (3) disposed on the moving shaft (1). A spring element (6) is coupled to the contact element (5) and configured to bias the contact element (5) such that, relative to the assembled state of the tap changer, the contact element (5) is preloaded along the longitudinal axis (L) of the moving shaft (1) in the direction of the moving shaft (1).

Description

Technical Field

[0001] This disclosure relates to a stationary contact unit, a contact system, and a tap changer. Background Technology

[0002] Tap changers in transformers are implemented, for example, as mechanisms that allow selection of variable turns ratios at different tap positions. Document US2005 / 205394 A1 discloses a load changing switch for tap changers, which has two pairs of permanent main contacts for each phase to be switched, wherein each of its fixed contacts is bridged by a movable permanent main contact. The fixed permanent main contacts consist of multiple contact plates hinged by contact springs such that the deflection direction of each contact plate corresponds, in its respective case, to the contact direction of the movable permanent main contacts.

[0003] Providing a stable and reliable mechanism is extremely challenging, given the electrical engagement of both the moving and stationary contacts.

[0004] Therefore, the objective is to provide a stationary contact unit for a tap changer, a contact system for a tap changer, and a tap changer, each realizing a stable and reliable mechanism for electrically engaging a movable contact and a stationary contact. Summary of the Invention

[0005] According to an embodiment, a stationary contact unit for a tap changer includes a contact body configured to be stationary relative to a movable contact on a moving axis of the tap changer. The movable contact is configured to be movable along the longitudinal axis of the moving axis. The stationary contact unit further includes at least one contact element pivotally coupled to the contact body and configured to establish electrical contact with the movable contact disposed on the moving axis. The stationary contact unit further includes a spring element coupled to the contact element and configured to bias the contact element such that, relative to the assembled state of the tap changer, the contact element is preloaded in the direction of the moving axis, allowing the contact element to pivot along the longitudinal axis of the moving axis.

[0006] According to an embodiment, the stationary contact unit includes two contact elements pivotally connected to the contact body and configured to establish corresponding electrical contact with a movable contact of the moving shaft. A spring element is connected to and disposed between the two contact elements along the longitudinal axis of the moving shaft, and is configured to bias the contact elements such that, relative to the assembled state of the tap changer, the two contact elements are preloaded along the direction of the moving shaft relative to the longitudinal axis of the moving shaft.

[0007] By using the described stationary contact unit, a safe and reliable mechanism for electrically engaging the movable and stationary contacts is feasible. The corresponding stationary contact unit can form the upper, lower, or intermediate electrical stationary contacts of the contact system for a preselector of an on-load tap changer. The aforementioned moving shaft and one or more movable contacts realize the components of this preselector that interact with one or more stationary contact units.

[0008] This disclosure recognizes that the conventional design of on-load tap changer preselectors is based on the need for a tie-in potential resistor mounted into the preselector structure. This requires additional space in the corresponding transformer box assembly and additional production time, making the product more complex and expensive.

[0009] This disclosure further recognizes that if the breaking speed on the preselector contact system is increased during the transient process of switching the preselector while the tap winding of the transformer remains at a floating potential, the use of transition resistors can be avoided.

[0010] The arrangement of stationary contact units and corresponding contact systems or preselectors allows for high-speed breaking at breaking speeds of, for example, 4-6 m / s. One or more pivotable contact elements can achieve double breaking because both sides of the interacting movable contacts break simultaneously.

[0011] According to another embodiment of the stationary contact unit, the corresponding contact element and the associated contact body each include contact surfaces facing each other, the contact surfaces being configured to restrict pivotal movement of the contact element relative to the contact body.

[0012] According to another embodiment of the stationary contact unit, the corresponding contact element includes a first arm and a second arm, wherein the first arm is pivotally coupled to an associated contact body, and the second arm is pivotally coupled to the first arm. This pivotable double-arm contact lever allows for beneficial mobility when interacting with a movable contact that moves and passes through the stationary contact unit.

[0013] According to another embodiment of the stationary contact unit, the first and second arms of the respective contact elements each include contact surfaces facing each other, the contact surfaces being configured to restrict pivoting movement of the second arm relative to the first arm. The two arms of the respective contact elements are configured to cooperate with each other to allow and restrict predetermined pivoting movement. For example, the stationary contact unit includes a contact element and is configured to implement the upper stationary contact of a preselector for a tap changer. A spring element pulls the contact element upward against a stop surface or contact surface, but the second arm is configured to pivot further upward in interaction with a moving contact that pushes it upward. In the opposite direction of movement, the moving contact pushes the second arm of the contact downward until the contact surface of the second arm contacts the contact surface of the first arm, and thus restricts the pivoting movement of the second arm relative to the first arm. Further pivoting movement of both arms together is still possible.

[0014] According to another embodiment of the stationary contact unit, the second arm of the corresponding contact element includes a chamfered or rounded end configured to establish corresponding electrical contact with the contact surface of the movable contact of the moving shaft relative to the assembled state of the tap changer. This configuration of the contact element enables low-resistance and low-wear contact during engagement with the corresponding contact surface of the movable contact, and also guides the movement of the second arm.

[0015] According to another embodiment, the stationary contact unit includes parallel contact elements that are stationarily coupled to the contact body. Each parallel contact element extends toward the moving shaft to establish corresponding electrical contact with the contact surface of the movable contact of the moving shaft relative to the assembled state of the tap changer. The contact elements are specifically designed as snap fingers and establish temporary contact with the movable contact at the moving shaft until the parallel contacts establish working contact and perform electrical switching. The parallel contacts provide current in the normal position of the selector or contact system. This achieves the stationary position before electrical switching begins. The selector provides current in the stationary position. During the switching process, the parallel contacts have disengaged when the moving shaft is in an intermediate position before releasing the snap fingers or contact elements. There may be a transition process without high current because the selector has disengaged before this.

[0016] According to an embodiment, a contact system for a tap changer includes: a linear moving shaft formed in an elongated shape primarily along a longitudinal axis; and a knife-shaped contact unit configured to be axially movable along the longitudinal axis of the moving shaft. The contact system further includes one or more embodiments of the aforementioned stationary contact units (at least considering the contact body) arranged statically relative to the knife-shaped contact units. One or more contact elements are also fixed relative to the longitudinal axis at a pivot point but are pivotable to a given extent.

[0017] In particular, the contact system can function as a preselector for tap changers and enables safe and reliable electrical switching. Since the contacts include embodiments of the stationary contact unit described above, features and characteristics of the stationary contact unit are also disclosed with respect to the contact system, and vice versa.

[0018] According to an embodiment, the contact system includes three stationary contact units, wherein a first stationary contact unit is configured to form an upper contact, a second stationary contact unit is configured to form a lower contact, and a third stationary contact unit is configured to form an intermediate contact between the first and second contacts relative to the longitudinal axis of the moving shaft. Each of the first and second contact units includes a contact element and a spring element that biases the associated contact element. The third contact unit includes two contact elements and a spring element that biases the two contact elements. A knife-shaped contact unit includes a plurality of movable contacts coupled to the moving shaft, the plurality of movable contacts being configured to establish electrical contact with one or more of the stationary contact units for electrical switching. This configuration of the stationary contact units and the contact system achieves an advantageous structure for a preselector that can quickly and safely achieve double disconnection and electrical switching.

[0019] According to another embodiment of the contact system, the knife-shaped contact unit includes at least one movable contact with two contact wing elements, wherein a funnel-shaped contact slot is defined between the two wing elements, the funnel-shaped contact slot being geometrically formed to mate with the parallel contact elements of the stationary contact unit. Due to this configuration, a very reliable and safe electrical contact can be established between the stationary contact unit and the movable contact for electrical switching.

[0020] According to another embodiment of the contact system, each of the two contact wing elements of the corresponding movable contact includes a corresponding groove and contact wall, the groove and contact wall being geometrically formed to mate with a corresponding pivotable contact element of the associated stationary contact unit. The aforementioned contact groove mates with a parallel contact, and the previously established temporary contact is achieved, for example, through the groove and the contact element forming a quick-acting finger.

[0021] For example, the contact wall defines one side boundary of the groove relative to the longitudinal axis of the movable shaft, such that the first and second states are adjustable when an electrical contact is formed between the corresponding pivotable contact element of the associated stationary contact unit and the movable contact of the knife-shaped contact unit. In the first state, the contact element is in contact with the contact wall, and in the second state, the contact element is arranged inside the groove and is not in contact with the contact wall and the wing element, while the parallel contact element is in contact with the wing element and the movable contact.

[0022] According to another embodiment of the contact system, the contact wall includes a chamfer or rounding, which is configured to establish a corresponding electrical contact with the pivotable contact element of the associated stationary contact unit. This configuration of the contact wall enables low-resistance and low-wear contact, particularly in conjunction with the rounded or chamfered ends of the contact element.

[0023] According to an embodiment, a tap changer includes the contact system of the preselector forming the tap changer described above, and a selector having one or more contact devices connected to the preselector for electrical switching. Since the tap changer includes the aforementioned contact system and stationary contact unit embodiments, features and characteristics of the contact system and / or stationary contact unit are also disclosed with respect to the tap changer, and vice versa.

[0024] The described embodiments of the stationary contact unit and contact system allow for accelerated preselector design in on-load tap changers by means of fast-acting contact fingers, enabling double disconnection of the tap changer circuit. The stationary contact unit, interacting with the movable contact, allows for accelerated disengagement of the preselector contact system by means of pivotable fast-acting contact fingers that store and release energy controlled by the cam profile of the movable contact.

[0025] The pivotally mounted quick-acting contact fingers of the corresponding stationary contact unit can provide the following characteristics: • During the movement of the low-speed vertical preselector shaft, a pair of quick-acting contact fingers are actuated by means of a spring element and energy is stored in them. • The cam profile of the movable contact of the selector moving shaft holds and releases the snap-action contact fingers, so that the snap-action contact fingers immediately disconnect the electrical circuit at high speed. • To perform the above actions, the quick-acting contact fingers include two arms or elements with a hinged structure. Only a single spring element is needed to move the contact fingers in the desired sequence. Attached Figure Description

[0026] Exemplary embodiments are explained below with the aid of schematic diagrams and reference numerals. The accompanying drawings show: Figures 1 to 3 This is a perspective view of an embodiment of a preselector for a tap changer, and Figures 4 to 9 It is used according to Figures 1 to 3 A cross-sectional view of an embodiment of the stationary contact unit of the preselector.

[0027] The accompanying drawings are included to provide further understanding. The same reference numerals denote elements or parts that have the same function. As long as elements or parts correspond to each other in function in different drawings, their description will not be repeated for each subsequent drawing. For clarity, elements may not have corresponding reference numerals in all drawings. Detailed Implementation

[0028] Figures 1 to 3 The perspective view illustrates different states of an embodiment of a contact system 30 implementing a preselector for a tap changer. The contact system 30 includes three stationary contact units 20 (see also...). Figures 4 to 6 The contact system 30 includes: a linear moving shaft 1, which is formed in an elongated shape primarily along a longitudinal axis L; and a knife-shaped contact unit 2, which is configured to be axially movable along the longitudinal axis L of the moving shaft 1. Three stationary contact units 20 are arranged stationary relative to the knife-shaped contact units 2.

[0029] The first stationary contact unit 21 is configured to form an upper contact unit, the second stationary contact unit 22 is configured to form a lower contact unit, and the third stationary contact unit 23 is configured to form an intermediate contact unit between the first contact unit 21 and the second contact unit 22 relative to the longitudinal axis L of the moving shaft 1 (see [link]). Figures 2 to 3 The first stationary contact unit 21 and the second stationary contact unit 22 each include a contact element 5 and a spring element 6 that biases the associated contact element 5. The respective spring element 6 is connected on one side to the associated pivotable contact element 5 to form a movable spring contact 15, and on the other side to a stationary spring contact element 14 (see [link to relevant documentation]). Figure 4 and Figure 7 The third contact unit 23 includes two contact elements 5 and a spring element 6 that biases the two contact elements 5. The spring element 6 of the third stationary contact unit 23 is connected to the two pivotable contact elements 5 on opposite sides. The contact elements 5 and the spring element 6 form corresponding quick-acting finger contacts.

[0030] Each contact element 5 is pivotally connected to the associated contact body 4 of the corresponding stationary contact unit 20 and is configured to establish electrical contact with the corresponding cam or movable contact 3 of the knife-shaped contact unit 2 arranged on the moving shaft 1.

[0031] The knife-shaped contact unit 2 includes two movable contacts 3 (an upper contact and a lower contact 3) connected vertically along a moving axis 1. Each movable contact 3 includes two contact wing elements 7, wherein the two wing elements 7 include corresponding inner contact surfaces 9, which together define a corresponding funnel-shaped contact slot 8, which is geometrically formed to mate with the parallel contact element 18 of the stationary contact unit 20. Each of the two wing elements 7 further includes a corresponding groove 10 and a contact wall 31, which are geometrically formed to mate with a corresponding pivotable contact element 5 of the associated stationary contact unit 20.

[0032] The contact wall 31 defines one side boundary of the corresponding groove 10 relative to the longitudinal axis L of the movable shaft 1, such that the first and second states are adjustable when an electrical contact is formed between the corresponding pivotable contact element 5 of the associated stationary contact unit 20 and the movable contact 3 of the knife-shaped contact unit 2. In the first state, the contact element 5 is in contact with the contact wall 31 (see...). Figure 2 , Figure 3 , Figure 6 and Figure 8 In the second state, the contact element 5 is arranged inside the groove 10 and does not contact the contact wall 31 (see...). Figure 1 , Figure 4 , Figure 5 , Figure 7 and Figure 9 The corresponding contact wall 31 includes a chamfer or rounded portion, which is configured to establish corresponding electrical contact with the pivotable contact elements 5 of the associated stationary contact units 20 or 21 to 23, respectively (see...). Figures 4 to 9 ).

[0033] Each contact element 5 includes a first arm 5a and a second arm 5b. The first arm 5a is pivotally connected to the associated contact body 4 about a first rotation axis R1. The second arm 5b is pivotally connected to the first arm 5a about a second rotation axis R2 (see [link to relevant documentation]). Figures 4 to 9 Each second arm 5b includes a chamfered or rounded end 26 configured to establish a corresponding electrical contact with the contact wall 31 of the movable contact 3.

[0034] Each contact element 5 has a first arm 5a and a second arm 5b, each having contact surfaces 25a, 25b facing each other. These contact surfaces are configured to restrict pivoting movement of the second arm 5b relative to the first arm 5a (see [link to contact element]). Figures 8 to 9 Each second arm 5b further includes a reinforcing portion in the region of its contact surface 25b to improve the operational stability of the corresponding interacting arms 5a, 5b.

[0035] Each stationary contact unit 20 has a parallel contact element 18 that is statically connected to the contact body 4. Each parallel contact element extends in the direction toward the moving axis 1 to establish a corresponding electrical contact with the corresponding contact surface 9 of the wing element 7 of the movable contact 3.

[0036] Furthermore, each contact element 5 or its first arm 5a and the associated contact body 4 include corresponding contact surfaces 19, 24, 25 facing each other, the contact surfaces being configured to restrict pivotal movement of the contact element 5 or its first arm 5a relative to the contact body 4 (see [link to contact surface]). Figures 8 to 9 The contact surface of the contact body 4 can be formed as the upper surface or the lower surface of the body (see...). Figure 4 and Figures 6 to 9) and / or formed as protruding pin 19 (see Figure 5 The protruding pin 19 of the third intermediate stationary contact unit 23 supports the contact element 5 in the normal position to prevent the contact element from being electrically connected to the cam or movable contact when the cam or movable contact 3 of the knife-shaped contact unit 2 is located between the two contact elements 5.

[0037] Additionally, each stationary contact unit 20 may include a locking element 13 to ensure that the first arm 5a and the second arm 5b are positioned relative to each other on one side (see [link]). Figure 4 ).

[0038] Figure 1 The diagram illustrates the state in which the parallel contact elements 18 of the first upper contact unit 21 and the third intermediate contact unit 23 are in contact with the movable contact 3 of the knife-shaped contact unit 2. The contact elements 5 of the first stationary contact unit 21 and the third stationary contact unit 23 are arranged inside the groove and do not contact the corresponding wing elements 7.

[0039] Figure 2 The diagram illustrates a state where the blade-shaped unit 2 moves downward and the contact element 5 of the first stationary contact unit 21 contacts the wall 31 of a wing element 7 of the upper movable contact 3. The upper contact element 5 of the third stationary contact unit 23 is not in contact, while the lower contact element 5 contacts the wall 31 of a wing element 7 of the lower movable contact 3. Figure 3 The image is shown from a lower perspective. Figure 2 The state.

[0040] For example, Figure 4 and Figure 5 The corresponding cross-sectional diagrams illustrate the positions of and Figure 1 The corresponding state is the first stationary contact unit 21 or the third stationary contact unit 23.

[0041] Figures 6 to 7 The corresponding cross-sectional diagram illustrates the second stationary contact unit 22 when the movable contact 3 moves downward to establish electrical contact with the corresponding parallel contact element 18. Figure 8 and Figure 9 and Figure 6 and Figure 7 The same, but only partially illustrated the other reference numerals.

[0042] The described contact system 30 can realize an acceleration drive system in which three contacts (e.g., +, 0, -) are located in the vertical direction. The slewing finger 5 or contact element 5 can be locked on one side by a locking element 13, which allows the two arms 5a, 5b to rotate together as a whole in a first direction and to rotate separately in a second opposite direction.

[0043] Pairs of parallel contact elements 18 are mounted on each stationary contact unit 20, forming a contact bridge between the stationary contact body 4 and the contact surface 9 on the knife-shaped movable contact 3. In the normal position, all quick-acting fingers 5 are disconnected from the cam 3 of the knife-shaped contact unit 2, thereby preventing parallel circuits, and current flows only through the pairs of parallel contact elements 18 (see [link to relevant documentation]). Figure 1 , Figure 4 , Figure 5 , Figure 7 and Figure 9 During the vertical movement of the preselector moving shaft 1 along the longitudinal axis L, the parallel contact element 18 disengages from the contact surface 9 of the corresponding movable contact 3. Simultaneously, the quick-acting fingers 5a and 5b are energized and maintain the potential between the stationary contact body 4 and the movable contact 3. The energy storage of the quick-acting fingers 5 is achieved by means of a spring and the contact wall 31 of the movable contact 3.

[0044] When the knife-shaped contact unit 2 reaches the intermediate position, a pair of fast-acting fingers 5 immediately disconnect the electrical circuit at high speed, for example, at a speed greater than 1 m / s, for example, at a speed of 3-7 m / s, or for example, at a speed of 5 m / s. This high-speed disconnection is much faster than conventional systems that can allow disconnection at speeds of 50 mm / s or 100 mm / s. Therefore, the described embodiment of the contact system 30 and its stationary contact unit 20 allows for double disconnection because both sides of the knife-shaped movable contact 3 disconnect simultaneously.

[0045] Therefore, there are two dielectric distances between the movable contact 3 and the disengaged stationary contact unit 23. Before reaching the end position of the preselector moving shaft 1 (see...) Figure 7 and Figure 9 The contact wall 31 presses down on the quick-acting finger 5, causing it to rotate (see...). Figure 6 and Figure 8 (This is followed by a repositioning and release, allowing it to remain in place at the end of the movement, ready for the next operation.) The sequence is the same in the other direction. Combining faster switching speeds with setting two dielectric distances enables extremely short arc / spark durations, improving the switching capability of the preselector or contact system 30 and reducing gas generation. The described embodiments further allow for the elimination of transition resistors in the preselector design, achieving a simple structure and safe, reliable operation.

[0046] The aforementioned Figures 1 to 9 The embodiments shown illustrate exemplary embodiments of the improved stationary contact unit 20, the improved contact system 30, and the corresponding tap changer; therefore, these embodiments do not constitute a complete list of all embodiments according to possible arrangements. The actual arrangement of the stationary contact unit 20, the contact system 30, and / or the tap changer may differ from the embodiments shown in the figures.

[0047] Figure Labels 1. Moving axis 2. Knife-shaped contact unit 3. Movable contact / cam of the knife-shaped contact unit 4. Contact body 5. Contact elements / quick-acting finger elements 5a First arm of contact element 5b Second arm of the contact element 6. Spring elements 7 wing elements 8. Contact slot 9. Contact Surface 10 Grooves 13 Locking elements 14. Static spring contact element 15 Movable spring contact 18 Parallel contact elements 19 pin components 20 stationary contact units 21 First Upper Stationary Contact Unit 22 Second Lower Stationary Contact Unit 23 Third intermediate stationary contact unit 24 Contact Surface 25 Contact Surface 25a Contact Surface 25b Contact Surface 26 The end of the second arm 27. Enhanced Section 30 Contact System / Preselector 31. Contact wall L-axis of the moving axis / preselector R1 First Rotational Axis R2 Second Rotating Shaft

Claims

1. A stationary contact unit (20) for a tap changer, the stationary contact unit comprising: - Contact body (4), the contact body is configured to be stationary relative to the movable contact of the moving shaft (1) of the tap changer, the movable contact being configured to be movable along the longitudinal axis (L) of the moving shaft (1). - At least one contact element (5), said at least one contact element being pivotally coupled to the contact body (4) and configured to establish electrical contact with a movable contact (3) arranged at the moving shaft (1), and - A spring element (6), which is connected to the contact element (5) and configured to bias the contact element (5) such that the contact element (5) is preloaded along the direction of the moving shaft (1) relative to the assembled state of the tap switch, and the contact element (5) is configured to pivot along the longitudinal axis (L) of the moving shaft (1).

2. The stationary contact unit (20) according to claim 1, comprising: Two contact elements (5) are pivotally connected to the contact body (4) and configured to establish corresponding electrical contact with the movable contact (3) of the moving shaft (1), wherein a spring element (6) is connected to the two contact elements (5) along the longitudinal axis (L) of the moving shaft (1) and disposed between them, the spring element being configured to bias the contact elements (5) such that, relative to the assembled state of the tap changer, the two contact elements (5) are preloaded along the direction of the moving shaft (1) relative to the longitudinal axis (L) of the moving shaft (1).

3. The stationary contact unit (20) according to any one of the preceding claims, wherein, The corresponding contact element (5) and the associated contact body (4) each include contact surfaces (19, 24, 25) facing each other, which are configured to restrict the pivotal movement of the contact element (5) relative to the contact body (4).

4. The stationary contact unit (20) according to any one of the preceding claims, wherein, The corresponding contact element (5) includes a first arm (5a) and a second arm (5b), wherein the first arm (5a) is pivotally connected to the associated contact body (4), and the second arm (5b) is pivotally connected to the first arm (5a).

5. The stationary contact unit (20) according to claim 4, wherein, The first arm (5a) and the second arm (5b) of the respective contact element (5) each include contact surfaces (25a, 25b) facing each other, the contact surfaces being configured to restrict pivotal movement of the second arm (5b) relative to the first arm (5a).

6. The stationary contact unit (20) according to claim 4 or 5, wherein, The second arm (5b) of the corresponding contact element (5) includes a chamfered or rounded end (26) configured to establish corresponding electrical contact with the contact surface (31) of the movable contact (3) of the moving shaft (1) relative to the assembly state of the tap changer.

7. The stationary contact unit (20) according to any one of the preceding claims, comprising: Parallel contact element (18) is statically connected to the contact body (4) and extends in a direction toward the moving shaft (1) to establish corresponding electrical contact with the contact surface (9) of the movable contact (3) of the moving shaft (1) relative to the assembly state of the tap changer.

8. A contact system (30) for a tap changer, the contact system comprising: - A linear translation axis (1), which is formed in an elongated shape mainly along the longitudinal axis (L). - A knife-shaped contact unit (2), the knife-shaped contact unit being configured to move axially along the longitudinal axis (L) of the moving shaft (1), and - One or more stationary contact units (20) according to any one of the preceding claims, the stationary contact units being arranged statically relative to the blade-shaped contact unit (2).

9. The contact system (30) according to claim 8, comprising: Three stationary contact units (20) are provided, wherein a first stationary contact unit (21) is configured to form an upper contact unit, a second stationary contact unit (22) is configured to form a lower contact unit, and a third stationary contact unit (23) is configured to form an intermediate contact unit between the first contact unit and the second contact unit (21, 22) relative to the longitudinal axis (L) of the moving shaft (1). The first contact unit and the second contact unit (21, 22) each include a contact element (5) and a spring element (6) that biases the associated contact element (5), and the third contact unit (23) includes two contact elements (5) and a spring element (6) that biases the two contact elements (5). The blade-shaped contact unit (2) includes a plurality of movable contacts (3) connected to the moving shaft (1), the plurality of movable contacts being configured to establish electrical contact with one or more of the stationary contact units (20) for electrical switching.

10. The contact system (30) according to claim 8 or 9, wherein, The blade-shaped contact unit (2) includes at least one movable contact (3) having two contact wing elements (7), wherein a funnel-shaped contact slot (8) is defined between the two wing elements (7), the funnel-shaped contact slot being geometrically formed in conjunction with the parallel contact element (18) of the stationary contact unit (20).

11. The contact system (30) according to any one of claims 8 to 10, wherein, The blade-shaped contact unit (2) includes at least one movable contact (3) having two contact wing elements (7), wherein each of the two wing elements (7) includes a corresponding groove (10) and a contact wall (31), the groove and the contact wall being geometrically formed to cooperate with a corresponding pivotable contact element (5) of the associated stationary contact unit (20).

12. The contact system (30) according to claim 11, wherein, The contact wall (31) defines one side boundary of the groove (10) relative to the longitudinal axis (L) of the movable shaft (1), such that when an electrical contact is formed between the corresponding pivotable contact element (5) of the associated stationary contact unit (20) and the movable contact (3) of the knife-shaped contact unit (2), a first state and a second state are adjustable, wherein in the first state the contact element (5) is in contact with the contact wall (31), and in the second state the contact element (5) is arranged inside the groove (10) without contact with the contact wall (31).

13. The contact system (30) according to claim 11 or 12, wherein, The contact wall (31) includes a chamfer or rounded portion, which is configured to establish a corresponding electrical contact with the pivotable contact element (5) of the associated stationary contact unit (20).

14. A tap changer, comprising: - The contact system (30) according to any one of claims 8 to 13, the contact system forming a preselector for the tap changer, and - A selector having one or more contact devices connected to the preselector for electrical switching.

Images