GB2527800A

GB2527800A - Circuit breaker

Info

Publication number: GB2527800A
Application number: GB1411830.1A
Authority: GB
Inventors: Paulus Geusendam; Gerhardus Leonardus Nitert; Marcel Van Dijk
Original assignee: Eaton Industries Netherlands BV
Current assignee: Danfoss Power Solutions II BV
Priority date: 2014-07-02
Filing date: 2014-07-02
Publication date: 2016-01-06
Also published as: WO2016001328A1; GB201411830D0

Abstract

A circuit breaker 1 comprises a switching device having two main contacts 7,10 moveable relative to each other within a housing, fixed and moveable electrode rods 8,11 respectively connected to first and second terminals 9,15 and contact means 14 for establishing electrical contact between the second terminal 15 and moveable electrode 11 in both the open and closed positions of the switching device. The contact means or connector comprises a first contact part 14 arranged on the housing in connection with the second terminal 15 and a second contact part (13, figure 1) arranged on the moveable electrode 11, wherein the second part is flexibly mounted in an axial direction of the moveable electrode 11. The first and second contact parts may be concentric rings and may further comprise an annular coil spring element arranged on their mutual contact surface. The flexible contact part may have radially extending curved flexible contact elements attached to a mounting ring 20 and may comprise a plurality of metal layers welded together at the first contact part 14 and the mounting ring 20 so that the metal layers can move relative to each other.

Description

Circuit breaker The invention relates to a Circuit breaker comprising: -an switching device having two contacts movable relative to each other aiid arranged within an insulation housing; -a fixed electrode rod mounted on one side of the switching device; -a movable electrode rod mounted on the other side of the switching device; -a first terminal arranged on the housing and electrically connected to the fixed electrode rod; -a second terminal for electrical connection with the movable electrode rod; and -contact means for establishing an electrical contact between the second terminal and the movable electrode rod in both the open position and the closed position of the switching device Such a Circuit breaker is for example known from US 2009218319. In this prior art circuit 2 0 breaker the movable electrode rod is electrically connected to the second terminal via a flexible electrical lead.

In medium voltage applications the switching device needs to be moved at high speed to get a solid contact. In order to achieve this high speed movement, the movable electrode rod also needs to move at high speed. To ensure a good electrical connection between the movable electrode rod and a fixed terminal, a flexible lead is permanently fixed between this rod and the fixed terminal.

When the switching device is in the open position, it is required, that the switching device can 3 0 be moved further, such that the switching device can be disconnected. It is known in the prior art to provide second contact means comprising two parts, one of which is arranged to the fixed terminal, while the other part of the second contact means moves along with the switching device towards the disconnected position.

The disadvantage of having two separate contact means is that each contact means provides a number of components and provides a contact resistance in the circuit breaker.

It is an object of the invention to provide a Circuit breaker according to the preamble, in which the disadvantages of the prior art are reduced.

This object is achieved with a Circuit breaker according to the preamble, which is characterized in that the contact means comprise a first contact part arranged on the housing and in electrical connection with the second terminal, and a second contact part arranged on 1 0 the movable electrode rod, wherein at least one of the first contact part and the second contact part is flexibly mounted in axial direction of the movable electrode rod.

By having a first contact part arranged on the housing and a second contact part arranged on the movable electrode rod, the contact between the second terminal and the movable electrode rod will be established when the switching device is moved from the disconnected position to the open position.

The flexibly mounted second contact part ensures that the movable rod of the switching device can be moved further between the open position and closed position, while maintaining a solid electrical connection between the movable rod and a fixed terminal.

So, with the invention only single contact means are provided which enable movement from the closed position, via the open position to the disconnected position. Due to the single contact means, the contact resistance is reduced and fewer components are needed to provide the same functionality within the Circuit breaker.

The switching device having the two contacts movable relative to each other could for example be a vacuum interrupter, a vacuum circuit breaker or a vacuum load-break switch.

3 0 In an embodiment of the Circuit breaker according to the invention the first contact part and second contact part are concentrically arranged.

A concentric arrangement is of advantage with typical electrode rods, which typically have a circular cross section. The concentric arrangement of the contact parts will ensure that the electrode rod will be loaded evenly when the contact opens and closes.

In a preferred embodiment of the Circuit breaker according to the invention the first contact part and second contact part are concentric rings and wherein the contact means further comprise a spring element arranged on the contact surface of the two concentric rings.

The spring element will provide some flexibility in the contact surface between the two 1 0 concentric rings, such that a solid contact is achieved, while some play can be present between the rings.

In a further embodiment of the Circuit breaker according to the invention the spring element is an annular coil spring.

In a further preferred embodiment of the Circuit breaker according to the invention the flexibly mounted contact part has radially extending curved flexible mounting elements.

These curved flexible mounting elements could for example be embodied as spring leaves, or as torsion springs or as a combination thereof These curved flexible mounting elements provide sufficient flexibility for the contact part, such that the movements of the movable rod can easily be followed when the switching device moves between the closed position and open position, During these movements, the contact means will ensure the solid electrical contact between the movable rod and a fixed terminal.

Preferably, the flexibly mounted contact part further has a mounting ring concentrically arranged to the contact part and to which the curved flexible mounting elements are attached.

With the mounting ring, the contact part can easily be mounted on either the electrode rod or on the inside of the housing, In a further preferred embodiment of the Circuit breaker according to the invention the flexibly mounted contact part is composed out of a plurality of metal layers, which are welded together at the contact part and at the mounting ring, such that the metal layers can move relative to each other at the mounting elements.

By composing the flexibly mounted contact part out of a plurality of metal layers, flexibility is easily obtained in the contact, while sufficient material is present to conduct the current through the contact.

In case higher amounts of curent need to be conducted through the switching device, two or 1 0 more contact means can be stacked, such that a larger amount of current can be conducted via the contact parts, These and other features of the invention will be elucidated in conjunction with the accompanying drawings.

Figure I shows a perspective cross-sectional view of an embodiment of a Circuit breaker according to the invention.

Figure 2 shows a perspective cross-sectional view of the contact means of figure 1.

Figure 3 shows a cross-sectional view of a flexible contact part of the contact means of figure 2.

Figures 4A -4C show the Circuit breaker of figure 1 in three different positions.

Figure t shows a perspective cross-sectional view of an embodiment of a Circuit breaker 1 according to the invention, The Circuit breaker 1 has an insulation housing 2, 3, 4, 5, A vacuum interrupter 6 is arranged within the insulation housing 2, 3, 4, 5. The vacuum interrupter 6 has a fixed main contact 7 arranged to an electrode rod 8 and electrically connected to a first terminal 9 accessible from the outside of the housing 2, 3, 4, 5.

The vacuum interrupter 6 has further a second, movable, main contact 10, which is arranged on a movable electrode rod 11. The movable rod 11 is operable by an insulated operation pin 12.

The movable electrode rod 11 is frirthermore provided with a flexible contact part 13, which is in contact with another contact part 14 to establish an electrical connection between the main contact 10 and the second terminal 15 arranged on the outside of the housing 2, 3, 4, 5.

Figure 2 shows a perspective cross-sectional view of the contact means 13, 14 of figure 1.

The other contact part 14 is ring shaped and arranged on the inside of the housing 2, 3, 4, 5.

The flexible contact part 13 comprises a ring-shaped contact ring 16, radially extending curved flexible mounting elements 17, 8, 19 and a mounting ring 20 with which the flexible contact 13 is arranged to the movable electrode rod 11.

The circumferential outer surfa.ce of the contact ring 16 is provided with grooves 21 for housing two annular coil springs 22, which ensure a solid contact between the contact ring 6 and the ring-shaped contact part 14.

Figure 3 shows a cross-sectional view of the flexible contact part 13. The flexible contact part 13 is build out of a plurality of stacked metal layers 23. At the position of the contact ring 16 and the mounting ring 20, the stacked metal layers 23 are welded together, such that a solid contact ring 16 and a solid mounting ring 20 is created, Accordingly, the flexible mounting elements 17, 18, 19 are composed out of loose bands of metal, as the metal layers are not welded together at this particular position.

Figure 4A shows the Circuit breaker according to the invention in a closed position. In this position both contacts 7, 10 of the vacuum interrupter 6 are pressed against each other.

3 0 The electrode rod 8 is electrically connected to the first terminal 9, while the movable electrode rod 11 is connected to the second terminal 15 via the mounting ring 20, the flexible mounting elements 17, 18, 19, the contact ring 16 and the ring-shaped contact part 14.

Figure 4B shows the Circuit breaker in an open position in which the operation pin U is pulled downward, such that the movable electrode rod 11 is moved down causing the two contacts 7, 10 of the vacuum interrupter to disconnect. Due to the flexibility of the mounting element 17, 18, 19, the movable electrode rod 11 stays in contact with the second terminal 15.

Figure 4C shows the Circuit breaker 1 in disconnected position. In this position, the operation pin 12 is moved further, such that the electrode rod 8 disconnects from the first temiinal 9 and the complete vacuum interrupter 6 is moved downward, As a result, the contact ring 16 will disconnect from the ring-shaped contact part 14, such that the vacuum interrupter 6 is frilly disconnected from both the first terminal 9 and the second terminal 15.

Claims

Claims 1. Circuit breaker (1) comprising: -a switching device having two contacts (7, 10) movable relative to each other and arranged within an insulation housing (2, 3, 4, 5); -a fixed electrode rod (8) mounted on one side of the switching device; -a movable electrode rod (ii) mounted on the other side of the switching device; -a first terminal (9) arranged on the housing (2, 3, 4, 5) and electrically connected to the fixed electrode rod (8); -a second terminal (15) for electrical connection with the movable electrode rod (11); and -contact means (13, 14) for establishing an electrical contact between the second terminal (15) and the movable electrode rod (11) in both the open position and the closed position of the switching device characterized in that the contact means (13, 14) comprise a first contact part (14) arranged on the housing (2, 3, 4, 5) and in electrical connection th the second terminal (15), and a second contact part (13) arranged on the movable electrode rod (11), wherein atleast one of the first contact part (14) and the second contact part (13) is flexibly mounted in axial direction of the movable electrode rod (11).
2. Circuit breaker (1) according to claim 1, wherein the first contact part (14) and second contact part (13) are concentrically arranged.
3. Circuit breaker (1) according to claim 2, wherein the first contact part (14) and second contact part (13) are concentric rings and wherein the contact means (13, 14) further comprise a spring element (22) arranged on the contact surface of the two concentric rings.
4. Circuit breaker (1) according to claim 3, wherein the spring element (22) is an annular coil spring.
5, Circuit breaker (1) according to one of the claims 3 or 4, wherein the flexibly mounted contact part (13) has radially extending curved flexible mounting elements (17, 18, 19).
6, Circuit breaker () according to claim 5, wherein the flexibly mounted contact part ( 3) further has a mounting ring (20) concentrically arranged to the contact part (H) and to which the curved flexible mounting elements (17, 18, 19) are attached.
7. Circuit breaker (1) according to claim 6, wherein the flexibly mounted contact part (13) is composed out of a plurality of metal layers (23), which are welded together at the contact part (14) 2md at the mounting ring (20), such that the metal layers (23) can move relative to each other at the mounting elements (17, 18, 19),