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 plurality of rollable guiding elements and a lever mechanism which 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.

Claims

1. 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 plurality of rollable guiding elements and a lever mechanism which is in contact with the rollable guiding elements and which is coupled to both the control cam and the contact rod of the vacuum interrupter, wherein the guiding elements each are configured to be rollable around a respective axis of rotation that is perpendicular to a longitudinal center axis 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 movement of the lever mechanism by means of rolling of the guiding elements.

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

3. System according to claim 1, wherein the lever mechanism is configured to be hingeless comprising: a t-shaped bushing including a cylindrical element and a lever connected to the cylindrical element, wherein the cylindrical element is arranged to be in contact to the contact rod, an upper and a lower guiding unit each comprising at least one guiding element arranged at an upper portion or a lower portion of the cylindrical element respectively with respect to the longitudinal axis of the cylindrical element, and a first lever driving element arranged between the control cam and the lever.

4. System according to claim 3, wherein the first lever driving element is formed as a rolling bearing, a roller or a bushing.

5. System according to claim 3, wherein the upper and lower guiding unit each comprising two guiding elements arranged at opposite sides of the cylindrical element with respect to the longitudinal axis of the cylindrical element and with respect to a plane spanned by the longitudinal axis of the cylindrical element and a longitudinal axis of the main driving shaft.

6. System according to claim 3, wherein the upper and lower guiding unit each comprising four guiding elements arranged perpendicularly to adjacent ones with respect to the longitudinal axis of the cylindrical element.

7. System according to claim 1, wherein the lever mechanism further comprises guiding pins and a second lever driving element formed as a rolling bearing, a roller or a bushing arranged between the control cam and the lever and between the guiding pins respectively.

8. Power diverter switch for an on-load tap changer, comprising: an insulating plate, a supporting plate, and a system according to claim 1, which is coupled to both the insulating plate and the supporting plate.

9. On-load tap changer for setting a gear ratio, comprising: a power diverter switch according to claim 8.

10. 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 plurality of rollable guiding elements and a lever mechanism which is in contact with the rollable guiding elements and which is coupled to both the control cam and the contact rod of the vacuum interrupter, wherein the guiding elements each are configured to be rollable around a respective axis of rotation that is perpendicular to a longitudinal center axis 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 movement of the lever mechanism by means of rolling of the guiding elements.

11. The system according to of claim 1, wherein the lever mechanism further comprises guiding pins and a second lever driving element formed as a rolling bearing, a roller or a bushing arranged between the control cam and the lever and between the guiding pins respectively.

12. The system according to claim 11, wherein the plurality of rollable guiding elements includes guiding elements formed as rolling bearings, rolls and/or bushings.

13. System according to claim 11, wherein the lever mechanism is configured to be hingeless comprising: a t-shaped bushing including a cylindrical element and a lever connected to the cylindrical element, wherein the cylindrical element is arranged to be in contact to the contact rod, an upper and a lower guiding unit each comprising at least one guiding element arranged at an upper portion or a lower portion of the cylindrical element respectively with respect to the longitudinal axis of the cylindrical element, and a first lever driving element arranged between the control cam and the lever.

14. The system according to claim 13, wherein the first lever driving element is formed as a rolling bearing, a roller or a bushing.

15. The system according to claim 14, wherein the upper and lower guiding unit each comprising two guiding elements arranged at opposite sides of the cylindrical element with respect to the longitudinal axis of the cylindrical element and with respect to a plane spanned by the longitudinal axis of the cylindrical element and a longitudinal axis of the main driving shaft.

16. The system according to claim 14, wherein the upper and lower guiding unit each comprising four guiding elements arranged perpendicularly to adjacent ones with respect to the longitudinal axis of the cylindrical element.

17. A power diverter switch for an on-load tap changer, comprising: an insulating plate, a supporting plate, and a system according to claim 16, which is coupled to both the insulating plate and the supporting plate.

18. An on-load tap changer for setting a gear ratio, comprising: a power diverter switch according to claim 17.

Description

BRIEF DRAWING DESCRIPTION

[0024] Example embodiments of the invention are explained in the following with the aid of schematic drawings and reference numbers. The figures show:

[0025] FIG. 1 illustrates an example embodiment of a system for controlling a vacuum interrupter for a power diverter switch in a side view;

[0026] FIG. 2 illustrates the system of FIG. 1 in another side view; and

[0027] FIG. 3 illustrates components of the system of the FIGS. 1 and 2 in a perspective view.

[0028] 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

[0029] FIG. 1 illustrates a side view of an embodiment of a system 1 for controlling a vacuum interrupter 30 of a power diverter switch. FIG. 2 illustrates another side view of the system 1 and FIG. 3 shows a perspective view of some components of the system 1.

[0030] 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 plurality of rollable guiding elements and a lever mechanism 21, 22, 23, 24 which is coupled to both the control cam 13 and the contact rod 31 of the vacuum interrupter 30. The guiding elements are formed as rolling bearings 25. 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 movement of the lever mechanism 21, 22, 23, 24 by means of rolling of the bearings 25.

[0031] 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.

[0032] The lever mechanism of the transmission unit 20 comprises a cylindrical element 24 and a lever 23 perpendicularly connected thereto. The cylindrical element 24 is further connected to the contact rod 31 of the VI 30. The cylindrical element 24 is guided by two groups of rolling bearings 25 distanced one above the other forming an upper and a lower guiding unit of guiding elements. According to the illustrated embodiments, each group consists of four bearings 25 located at an angle of approximately 90° relative to each other with respect to a central axis L2 of the cylindrical element 24 and/or the VI 30. Thus, the illustrated embodiment of the system 1 comprises eight rolling bearings 25 to provide stable and reliable guidance. Thus, with respect to the central axis L2 the transmission unit 20 counteracts an unwanted tilt of the cylindrical element 24 and contributes to a secure and reliable movement of the contact rod 31 and separation of the electrical contacts of the VI 30.

[0033] The bearings 25 are mounted on a stationary hollow holder 29 with a slot on one side, in which the perpendicular lever 23 can move. The system 1 comprises two further bearings which are mounted on the lever 23 and which realize a first lever bearing 21 and a second lever bearing 22. The control cam 13 is a specially shaped cylindrical cam and is configured to act on the first lever bearing 21 by applying a force parallel to the central axis L2 of the VI 30. The second lever bearing 22 is configured to move between two guiding pins 28 with a relative small gap such that the second lever bearing 22 touches only one guiding pin 28 or the other (see FIG. 3). Alternatively, the guiding pins 28 and the second lever bearing 22 can be arranged at the opposite side of the cylindrical element 24, for example, with respect to the central axis L2 interacting with an elongated lever 23. Such a mechanism respectively enables to prevent unwanted rotation of the contact rod 31 around its axis which corresponds to the central axis L2.

[0034] Moreover, in order to contribute to a space-saving design of the system 1 two contact springs 27 are placed on both sides of the stationary holder 29 with the bearings 25. These contact springs 27 are driven by the contact rod 31 using a common strap (see FIG. 2).

[0035] 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 without any hinges, due to the described structure of the transmission unit 20. The contact rod 31 of the VI 30 is guided straight between the two sets of four rolling bearings 25, which can be formed as rollers and/or bushings alternatively. Thus, it is possible for the point of application of the force needed to open the VI 30 to be displaced away from its longitudinal axis L2.

[0036] The main driving shaft drives the control cam 13 which acts on the first lever bearing 21 that is mounted on the cylindrical guided part realized by the cylindrical element 24 with perpendicular lever 23. Such a mechanism enables a simple but reliable way of actuating the contact rod 31—directly, without any additional elements with the corresponding unwanted gaps and unwanted wear in hinges, for example. There is only rolling friction and no friction in sliding present in this mechanism due to the rollable guiding elements and the hingeless lever mechanism. The described rollable bearings 25 beneficially operate using a small predetermined gap between the bearings 25 and the cylindrical element 24 such that there is a slight guiding contact to one of the upper and/or lower bearings 25, at least.

[0037] In particular, such a system 1 is suitable when an interaxial distance between the central axis L2 of the VI 30 and a central axis L1 of the main driving shaft 10 must be minimal or relatively small. Moreover, due to the possibility of saving hinges the influence of low temperatures is reduced as well because hinges deteriorate their performance at low temperatures around −20° C. to −40° C., for example.

REFERENCE NUMERALS

[0038] 1 system for controlling a vacuum interrupter [0039] 10 main driving shaft [0040] 11 stationary contact board [0041] 12 insulating plate [0042] 13 control cam [0043] 14 supporting plate [0044] 20 transmission unit [0045] 21 first lever bearing [0046] 22 second lever bearing [0047] 23 lever [0048] 24 cylindrical element [0049] 25 rolling bearing [0050] 26 stationary holder [0051] 27 contact spring [0052] 28 guiding pin [0053] 29 stationary holder [0054] 30 vacuum interrupter [0055] 31 contact rod [0056] L2 longitudinal axis of the main driving shaft [0057] L2 longitudinal axis of the cylindrical element/vacuum interrupter