SYSTEM FOR CONTROLLING A VACUUM INTERRUPTER FOR A POWER DIVERTER SWITCH, A POWER DIVERTER SWITCH AND AN ON-LOAD TAP CHANGER

Abstract

A system for controlling a vacuum interrupter for a power diverter switch comprises a main driving shaft which is configured to drive the control cam. The system further comprises the vacuum interrupter which is configured to separate electrical contacts in a vacuum by use of a contact rod, and a transmission unit which is configured to transmit the force generated by the main driving shaft to the contact rod. The transmission unit comprises a lever mechanism with a plurality of rollable guiding elements and a rotatable fork-shaped lever, the lever mechanism is coupled to both the control cam and the contact rod of the vacuum interrupter such that a rotation of the control cam generated by the main driving shaft causes a movement of the contact rod due to a guided rotation of the fork-shaped lever by means of rolling of the guiding elements.

Claims

1. A system for controlling a vacuum interrupter for a power diverter switch, comprising: a main driving shaft which is coupled to a control cam and which is configured to drive the control cam, the vacuum interrupter which is configured to separate electrical contacts in a vacuum by use of a contact rod, and a transmission unit which is configured to transmit the force generated by the main driving shaft to the contact rod, wherein the transmission unit comprises a lever mechanism with a plurality of rollable guiding elements and a rotatable fork-shaped lever, the guiding elements are in contact with the fork-shaped lever and each are configured to be rollable around a respective axis of rotation that is perpendicular to a longitudinal center axis of the vacuum interrupter, the lever mechanism is coupled to both the control cam and the contact rod of the vacuum interrupter such that a rotation of the control cam generated by the main driving shaft causes a movement of the contact rod due to a guided rotation of the fork-shaped lever by means of rolling of the guiding elements.

2. The system according to claim 1, wherein the plurality of rollable guiding elements includes guiding elements formed as rolling bearings, rolls and/or bushings.

3. The system according to claim 1, wherein the fork-shaped lever is rotatable with respect to a rotation axis of an axle perpendicular to the center axis of the vacuum interrupter and wherein the lever mechanism comprises two guiding units each comprising at least one inner guiding element with respect to the center axis of the vacuum interrupter arranged to guide a rotation of the fork-shaped lever around its rotation axis.

4. The system according to claim 3, wherein the two guiding units each further comprises an outer guiding element, a guiding pin and a limiter, wherein the respective outer guiding element is arranged between the inner guiding element and the guiding pin with respect to the center axis of the vacuum interrupter further limited by the limiter to guide a rotation of the fork-shaped lever along the center axis of the vacuum interrupter.

5. The system according to claim 1, wherein the fork-shaped lever is formed as an L-shaped bilateral fork comprising four protrusions facing a center axis of the vacuum interrupter, wherein a respective guiding element is arranged between two protrusions of the bilateral fork with respect to the center axis of the vacuum interrupter.

6. The system according to claim 1, wherein the lever mechanism comprises: a bushing configured to interact with the fork-shaped lever; a bushing nut configured to limit a position of the bushing; and a stud connected to the contact rod, wherein the bushing, the bushing nut and the stud are arranged along a center axis of the vacuum interrupter, wherein the bushing is arranged between the contact rod and the bushing nut with respect to the center axis of the vacuum interrupter, and wherein the stud is arranged inside the bushing such that a predetermined gap between the bushing and the stud is formed enabling rotation of the bushing around the center axis of the vacuum interrupter.

7. The system according to claim 6, wherein the lever mechanism further comprises fixing means configured to secure a predetermined position of the bushing.

8. A power diverter switch for an on-load tap changer, comprising: an insulating plate; a supporting plate; and a system coupled to both the insulating plate and the supporting plate, the system comprising: a main driving shaft which is coupled to a control cam and which is configured to drive the control cam; the vacuum interrupter which is configured to separate electrical contacts in a vacuum by use of a contact rod; and a transmission unit which is configured to transmit the force generated by the main driving shaft to the contact rod, wherein the transmission unit comprises a lever mechanism with a plurality of rollable guiding elements and a rotatable fork-shaped lever, the guiding elements are in contact with the fork-shaped lever and each are configured to be rollable around a respective axis of rotation that is perpendicular to a longitudinal center axis of the vacuum interrupter, the lever mechanism is coupled to both the control cam and the contact rod of the vacuum interrupter such that a rotation of the control cam generated by the main driving shaft causes a movement of the contact rod due to a guided rotation of the fork-shaped lever by means of rolling of the guiding elements.

9. An on-load tap changer for setting a gear ratio, comprising: a power diverter switch comprising: an insulating plate; a supporting plate; and a system coupled to both the insulating plate and the supporting plate, the system comprising: a main driving shaft which is coupled to a control cam and which is configured to drive the control cam; the vacuum interrupter which is configured to separate electrical contacts in a vacuum by use of a contact rod; and a transmission unit which is configured to transmit the force generated by the main driving shaft to the contact rod, wherein the transmission unit comprises a lever mechanism with a plurality of rollable guiding elements and a rotatable fork-shaped lever, the guiding elements are in contact with the fork-shaped lever and each are configured to be rollable around a respective axis of rotation that is perpendicular to a longitudinal center axis of the vacuum interrupter, the lever mechanism is coupled to both the control cam and the contact rod of the vacuum interrupter such that a rotation of the control cam generated by the main driving shaft causes a movement of the contact rod due to a guided rotation of the fork-shaped lever by means of rolling of the guiding elements.

10. The power diverter switch of claim 8, wherein the plurality of rollable guiding elements includes guiding elements formed as rolling bearings, rolls and/or bushings.

11. The power diverter switch of claim 8, wherein the fork-shaped lever is rotatable with respect to a rotation axis of an axle perpendicular to the center axis of the vacuum interrupter and wherein the lever mechanism comprises two guiding units each comprising at least one inner guiding element with respect to the center axis of the vacuum interrupter arranged to guide a rotation of the fork-shaped lever around its rotation axis.

12. The power diverter switch of claim 11, wherein the two guiding units each further comprises an outer guiding element, a guiding pin and a limiter, wherein the respective outer guiding element is arranged between the inner guiding element and the guiding pin with respect to the center axis of the vacuum interrupter further limited by the limiter to guide a rotation of the fork-shaped lever along the center axis of the vacuum interrupter.

13. The power diverter switch of claim 8, wherein the fork-shaped lever is formed as an L-shaped bilateral fork comprising four protrusions facing a center axis of the vacuum interrupter, wherein a respective guiding element is arranged between two protrusions of the bilateral fork with respect to the center axis of the vacuum interrupter.

14. The power diverter switch of claim 8, wherein the lever mechanism comprises: a bushing configured to interact with the fork-shaped lever; a bushing nut configured to limit a position of the bushing; and a stud connected to the contact rod, wherein the bushing, the bushing nut and the stud are arranged along a center axis of the vacuum interrupter, wherein the bushing is arranged between the contact rod and the bushing nut with respect to the center axis of the vacuum interrupter, and wherein the stud is arranged inside the bushing such that a predetermined gap between the bushing and the stud is formed enabling rotation of the bushing around the center axis of the vacuum interrupter.

15. The power diverter switch of claim 14, wherein the lever mechanism further comprises fixing means configured to secure a predetermined position of the bushing.

16. The on-load tap changer of claim 9, wherein the plurality of rollable guiding elements includes guiding elements formed as rolling bearings, rolls and/or bushings.

17. The on-load tap changer of claim 9, wherein the fork-shaped lever is rotatable with respect to a rotation axis of an axle perpendicular to the center axis of the vacuum interrupter and wherein the lever mechanism comprises two guiding units each comprising at least one inner guiding element with respect to the center axis of the vacuum interrupter arranged to guide a rotation of the fork-shaped lever around its rotation axis.

18. The on-load tap changer of claim 17, wherein the two guiding units each further comprises an outer guiding element, a guiding pin and a limiter, wherein the respective outer guiding element is arranged between the inner guiding element and the guiding pin with respect to the center axis of the vacuum interrupter further limited by the limiter to guide a rotation of the fork-shaped lever along the center axis of the vacuum interrupter.

19. The on-load tap changer of claim 9, wherein the fork-shaped lever is formed as an L-shaped bilateral fork comprising four protrusions facing a center axis of the vacuum interrupter, wherein a respective guiding element is arranged between two protrusions of the bilateral fork with respect to the center axis of the vacuum interrupter.

20. The on-load tap changer of claim 9, wherein the lever mechanism comprises: a bushing configured to interact with the fork-shaped lever; a bushing nut configured to limit a position of the bushing; and a stud connected to the contact rod, wherein the bushing, the bushing nut and the stud are arranged along a center axis of the vacuum interrupter, wherein the bushing is arranged between the contact rod and the bushing nut with respect to the center axis of the vacuum interrupter, and wherein the stud is arranged inside the bushing such that a predetermined gap between the bushing and the stud is formed enabling rotation of the bushing around the center axis of the vacuum interrupter.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0030] FIG. 1 is an exemplary embodiment of a system for controlling a vacuum interrupter for a power diverter switch in a perspective view;

[0031] FIG. 2 is a side view of the system of FIG. 1 illustrating a partial cross section view; and

[0032] FIG. 3 is a detailed view of components according to the system of FIGS. 1 and 2 in cross section view.

[0033] Identical reference numbers designate elements or components with identical functions. In so far as elements or components correspond to one another in terms of their function in different figures, the description thereof is not repeated for each of the following figures. For the sake of clarity elements might not appear with corresponding reference symbols in all figures possibly.

DETAILED DESCRIPTION

[0034] FIG. 1 illustrates a perspective view of an embodiment of a system 1 for controlling a vacuum interrupter 30 of a power diverter switch. FIG. 2 illustrates in a side view a partial cross section of the system 1. FIG. 3 shows an enlarged cross section side view of components of the system 1.

[0035] The system 1 includes a main driving shaft 10 which is coupled to a control cam 13 and which is configured to drive the control cam 13. The vacuum interrupter (VI) 30 which is configured to separate electrical contacts in a vacuum by use of a contact rod 31. A transmission unit 20 which is configured to transmit the force generated by the main driving shaft 10 to the contact rod 31. The transmission unit 20 comprises a lever mechanism including a plurality of rollable guiding elements and a fork-shaped lever 22 which is coupled to both the control cam 13 and the contact rod 31 of the VI 30. The guiding elements are formed as rolling bearings 25, 26. Thus, a rotation of the control cam 13 generated by the main driving shaft 10 causes a movement of the contact rod 31 due to a guided rotation of the fork-shaped lever 22 by means of rolling of the bearings 25, 26.

[0036] The system 1 realizes a component of a power diverter switch for an on-load tap changer. The diverter switch further comprises a lower supporting steel plate 14 and an upper insulating plate 12 on which is mounted a stationary contact board 11, carrying the VI 30. The control cam 13 is fastened to the main driving shaft 10.

[0037] The lever mechanism of the transmission unit 20 comprises a special guiding element 24 interacting with the fork-shaped lever 22. The contact rod 31 of the VI 30 is guided straight by means of the lever mechanism and the transmission unit 20. The transmission unit 20 comprises two groups of two rolling bearings including the bearings 25 and 26, arranged on an axis perpendicular to a longitudinal or center axis L2 of the VI 30.

[0038] The outer pair of rolling bearings 26 are arranged bilaterally on both sides with respect to the center axis L2 of the VI 30. The outer pair of bearings 26 provides guidance of the lever mechanism along the center axis L2 of the VI 30 by means of grooves or gaps predetermined arranged between the bearing 26 and corresponding bearing limiter 32 adjacent to an outer surface of the bearings 26. These predefined grooves or gaps further contributes to prevent an unwanted rotation of the lever mechanism around the center axis L2 of the VI 30 as well.

[0039] Guiding pins 28 that can be arranged with rolls are used as lateral restraints next to an outer side of the bearings 26 with respect to the center axis L2 of the VI 30, respectively.

[0040] The guiding element 24 is driven by the L-fork-shaped lever 22 which is rotatable around on a fixed axle 29 and mounted on roller bearings. At one end, the lever 22 is shaped like a bilateral fork, which contacts with the inner pair of bearings 25 of the guiding element 24, thus transmitting the movement of the contact rod 31 of the VI 30. At the other end of the lever 22 there is a lever bearing 21 which is driven directly by the control cam 13.

[0041] The guided element 24 has a central threaded hole that coincides with the center axis L2 of the contact rod 31 and the VI 30 at its nominal position. In this hole is mounted a bushing 23 with external thread (see FIGS. 2 and 3). The bushing 23 is formed as a sleeve and inside the bushing 23 there is a stud 34 displaced, which is connected to the contact rod 31 of the VI 30. The stud 34 is used for fixing a current carrying plate 35 as well. The bushing 23 is limited by a hexagonal shaped support of the stud 34 above and a special bushing nut 38 below with respect to the center axis L2. A small, predetermined gap of approximately 0.02-0.05 mm is realized between the bushing 23 and the bushing nut 38. After adjustment of this gap, the bushing nut 38 can be fixed by means of a pin 39, for example. In this way the thread bushing 23 can be rotated freely around the center axis L2 and can be used for precise adjustment of a contact gap of the VI 30. The contact gap is located inside the vacuum interrupter 30 relating to two contact plates. When the VI 30 is opened these plates are separated on a specific distance and the current flow is disconnected. This distance is defined by the manufacturer of the VI 30 and should be in a tolerance frame. The bushing 23 can be secured against self-untightening by fixing means of a screw 36 and a special bushing limiter 33.

[0042] The bushing 23 and the stud 34 inside are arranged such that there is a further gap 40 between the bushing 23 and the stud 34, which allows to compensate manufacturing and/or alignment errors between the longitudinal center axis L2 of the VI 30 and a longitudinal center axis L1 of the main driving shaft 10.

[0043] Moreover, a contact spring 27 and corresponding adjusting spring nut 37 are arranged below the bushing 23 and the bushing nut 38 to provide a biased configuration with respect to the contact rod 31. Alternatively, in order to contribute to a space-saving design of the system 1 two contact springs could be placed on both sides with respect to the center axis L2. These contact springs could be driven by the contact rod 31 using a common strap.

[0044] The described system 1 provides a reliable mechanism for direct control of the vacuum interrupter 30 in the power diverter switch for an on-load tap changer. The structure of the system 1 is clear and enables a simple driving mechanism for the VI 30. Due to the rollable guiding elements 25, 26 and the fork-shaped lever 22 the system 1 enables a reliably directed movement of the contact rod 31 and thus a secure separation of the electrical contacts of the VI 30. Moreover, the described system 1 even allows misalignment of the VI 30 to certain degree.

REFERENCE NUMERALS

[0045] 1 system for controlling a vacuum interrupter [0046] 10 main driving shaft [0047] 11 stationary contact board [0048] 12 insulating plate [0049] 13 control cam [0050] 14 supporting plate [0051] transmission unit [0052] 21 lever bearing [0053] 22 fork-shaped lever [0054] 23 bushing with external thread [0055] 24 guiding element [0056] 25 inner rolling bearing [0057] 26 outer rolling bearing [0058] 27 contact spring [0059] 28 guiding pin [0060] 29 axle [0061] 30 vacuum interrupter [0062] 31 contact rod [0063] 32 bearing limiter [0064] 33 bushing limiter [0065] 34 stud [0066] 35 current carrying plate [0067] 36 screw [0068] 37 spring nut [0069] 38 bushing nut [0070] 39 fixing pin [0071] 40 gap [0072] L1 longitudinal axis of the main driving shaft [0073] L2 longitudinal axis of the cylindrical element/vacuum interrupter