WO2015044053A1

WO2015044053A1 - Switching gear

Info

Publication number: WO2015044053A1
Application number: PCT/EP2014/070022
Authority: WO
Inventors: Aniruddha KULKARNI; Nilesh WARAD; Sunil KUNCHE
Original assignee: Eaton Industries (Netherlands) B.V.
Priority date: 2013-09-30
Filing date: 2014-09-19
Publication date: 2015-04-02
Also published as: BR112016006868A2; CN105594079B; GB201317263D0; EP3053229A1; CN105594079A; ZA201602459B

Abstract

The invention relates to switching gear comprising: - a frame; - a main contact block (3) arranged to the frame and linearly movable between a disconnected position and a connected position; - an auxiliary contact block (4) arranged to the frame and movable parallel to the main contact block between a disconnected position and a connected position; - an operating lever (6); - a switch mechanism for disconnecting and connecting the axial movement and the rotation of the operating lever to the linear movement of the main contact block and the auxiliary contact block, such that from the disconnected position of both the main contact block (3) and the auxiliary contact block (3), first the auxiliary contact block is moved towards the connected position and after the auxiliary contact block has reached the connected position, the main contact block is moved towards the connected position.

Description

SWITCHING GEAR

The invention relates to switching gear like for medium- voltage applications. Switching gear is typically arranged in a cabinet. The back- wall of this cabinet is provided with main busbars to which the switching gear needs to connect. This switching gear comprises safety circuitry and actuators to make or brake contact between busbars. The switching gear for example provides a device, like a pump, electric motor or electric valve, with power switched from the main busbars via this switching gear and ensures that the power can be switched off and turned on easily. Furthermore, auxiliary contacts are provided which are used for testing purposes.

Such switching gear is typically arranged in drawers in the cabinet. This makes it easy to exchange switching gear, when a malfunction is detected.

For maintenance and problem solving, it is necessary that the switching gear can be tested. For this purpose, the switching gear has to be disconnected from the busbars. It is also desired that in such a test position the switching gear is still connected to an auxiliary connector such that different components of the switching gear can be tested.

With a typical draw-out switch, the switch is partially pulled out of the cabinet such that the draw-out switch is disconnected from the busbars and the switching gear can be tested. In this test position the switching gear is connected to or still connected to an auxiliary connector for testing the switching gear.

The draw-out switch is pulled out further to truly disconnect the switching gear. In this position the draw-out switching device can be removed safely.

Known draw-out switching devices are manually operated to position them in the desired position. The position is often indicated by marks arranged on the base frame. It is however difficult to position the switching device accurately in the correct position.

Some known draw-out switching devices are provided with a positioning mechanism in which one has to use a ratchet to rotate a screw spindle, which moves the sub-frame with the switching gear. An indicator is arranged with the positioning mechanism for indicating in which position the draw-out switching device is moved. The use of a ratchet to rotate a screw spindle, takes a relative long time for moving the switching device to the desired position.

Another disadvantage is that the draw-out switching gear sticks out of the cabinet, when it is put in the test position or the disconnected position.

It is an object of the invention to reduce or even remove the above mentioned disadvantages.

This object is achieved with switching gear according to the invention, which switching gear comprises:

- a frame;

- a main contact block arranged to the frame and linear movable between a disconnected position and a connected position;

- an auxiliary contact block arranged to the frame and movable parallel to the main contact block between a disconnected position and a connected position;

- an operating lever;

- a switch mechanism for disconnecting and connecting the axial movement and the rotation of the operating lever to the linear movement of the main contact block and the auxiliary contact block, such that from the disconnected position of both the main contact block and the auxiliary contact block, first the auxiliary contact block is moved towards the connected position and after the auxiliary contact block has reached the connected position, the main contact block is moved towards the connected position.

Because the main contact block and the auxiliary contact block are movable arranged to the frame, it is no longer required to move the frame, i.e. pull-out the drawer, to bring the switching gear in a testing position or a disconnected position. The main contact block and the auxiliary contact block are moved between their respective positions by operating the operating lever. The axial movement and / or the rotation of the lever is transferred to the movement of the main contact block and the the auxiliary contact block by a common known method, like gears or rod system. The switch mechanism ensures that the main contact block and auxiliary contact block are not moved in an undesired order. For example, it is not desired to move the auxiliary contact block from the connected to the disconnected position, while the main contact block is still in the connected position.

In a preferred embodiment of the switching gear according to the invention the switch mechanism comprises two parts, one part being arranged to the main contact block and one part being arranged to the auxiliary contact block, and a force defined connector for connecting the two parts.

When the main contact block is advanced forward by the operating lever from the disconnected position, it will take along with it the auxiliary contact block, which is connected to the main block via the force defined connector. When the switching gear is designed, such that the auxiliary contact block will reach the connected position first and the main contact block will still be forced forward, the force defined connector will disconnect when the operating force on the operating lever exceeds a certain threshold. Then the main contact block can move further towards the connected position, while the auxiliary contact block remains in the connected position.

The reverse will take place when the movement of the main contact block is reversed. As soon the main contact block arrives at the auxiliary contact block, such that the connector parts can connect, the main block will take the auxiliary contact block along back to both their disconnected positions.

In another embodiment of the switching gear according to the invention the connector comprises a spring means for clamping the two parts of the switch mechanism together. Sufficient force can be obtained with a spring to have the connector parts being connected when moving the auxiliary contact block from the disconnected position to the connected position, while making the connector parts disconnect when the main contact block is moved further, while not having to exert excessive force on the operating lever for the parts to disconnect.

In yet another embodiment of the switching gear according to the invention the connector comprises a magnet for keeping the two parts of the switch mechanism together by magnetic force. Instead of a spring, it is also possible to use magnetic force.

In another preferred embodiment of the switching gear according to the invention one of the main contact block and the auxiliary contact block is moved by the rotation of the operating lever, while the other of the main contact block and the auxiliary contact block is moved by the linear movement of the operating lever, and wherein the switch mechanism comprising blocking means for alternately blocking the linear movement and the rotation of the operating lever. The blocking means of this embodiment ensure that either the operating lever can be axially moved or can be rotated, but cannot be moved and rotated simultaneously. So, for example, the auxiliary contact block is moved from the disconnected position to the connected position by axially moving the operating lever. When the auxiliary contact block reaches the connected position, the blocking means will block further axial movement of the operating lever, while enabling rotating of operating lever, which will make it possible to move the main contact block from the disconnected position to the connected position.

In another embodiment of the switching gear according to the invention the operating lever comprises at least one longitudinal groove and at least one circumferential groove and at least one cam arranged to the frame running in the grooves, such that when the cam is in the longitudinal groove, the operating lever can only be linearly moved, and when the can is in the circumferential groove, the operating lever can only be rotated.

With the grooves and cam it is possible to orchestrate the axial movement and rotation of the operating lever such, that the main contact block and the auxiliary contact block are moved in the correct order. Preferably, the operating lever is connected to the main contact block by a threaded portion, such that the main contact block is moved by rotating the operating lever.

With a rotating movement of the operating lever, it is possible to generated higher force, than with a single axial movement. This could be of advantage for connecting the main contact block to the busbars, which typically would require more force than connecting the auxiliary contacts.

These and other features of the invention will be elucidated in conjunction with the accompanying drawings.

Figure 1 shows a schematic perspective view of switch gear according to the invention.

Figures 2A - 2C shows a schematic view of a first embodiment of switching gear according to the invention in three different positions.

Figures 3 A - 3C shows a schematic view of a second embodiment of switching gear according to the invention in three different positions. Figure 1 shows a draw-out switch 1, which is typically arranged in a cabinet (not shown). Inside such a cabinet busbars 2 are arranged which provide power for the draw-out switch 1. This power is provided to the draw-out switch via the main contact block 3.

Furthermore, the draw-out switch 1 has an auxiliary contact block 4, which can be brought into contact with contacts 5 arranged in the cabinet, such that different components of the switching gear can be tested.

As described in the preamble, it is required that the switching gear 1 can be put in a

'disconnected position' (fig 2A), in which both the main contact block 3 and auxiliary contact block 4 are disconnected, in a 'test position' (fig 2B) with only the auxiliary contact block 4 connected and in a 'connected position' (fig 2C)in which both contact blocks 3, 4 are connected. According to the invention this is achieved by linear movement of the main contact block 3 and linear movement of the auxiliary block 4. This movement is obtained by controlling the operating lever 6.

Figures 2A - 2C show a schematic view of a first embodiment 10 of switching gear like shown in figure 1.

Figure 2A shows the position of the switching gear 10, in which the main contact block 3 is disconnected from the busbars 2 and in which the auxiliary contact block 4 is disconnected from the contacts 5 in the cabinet.

The main contact block 3 is connected to the operating lever 6 via the threaded shaft 11. By rotating the operating lever 6, the main contact block can be moved linearly.

The auxiliary contact block 4 is connected to the main contact block 3 via a connector 12, 13. This connector 12, 13, 14 has two parts 12, 13, which are axially arranged and clamped to each other by spring loaded balls 14(Ball catch latch), which provide a snap-like connection.

Now, when the operating lever 6 is rotated, the main contact block 3 will be moved towards the busbars 2. At the same time, the auxiliary contact block 4 will move towards the contacts 5 as a result of the connection via the connector 12, 13, 14 to the main contact block 3.

Figure 2B shows the position in which the auxiliary contact block 4 is fully connected to the contacts 5. When the operating lever 6 is further rotated, the auxiliary contact block 4 will no longer be able to move forward, while the main contact block 3 can still get closer to the busbars 2. As a result, an increasing force will be subjected to the connector 12, 13, 14, which will result in releasing the snap connection from the spring loaded balls 14.

When the two parts 12, 13 are released from each other, the main contact block 3 can move further, such that it will be connected to the busbars 2, as shown in figure 2C.

When the operating lever 6 is now rotated in the reverse direction, the main contact block 3 will move away from the busbars 2 such that the part 12 of the connector will be slided into the part 13 and the spring loaded balls 14 can clamp both parts 12, 13 together. When the operating lever 6 is rotated further, the auxiliary contact block 4 is taken along with the main contact block 3, such that the switching gear 10 arrives back in the position shown in figure 2A.

In isolated position (Fig 2 A) depending on the position of the contact 5 in cabinet, auxiliary contact block 4 can be kept at a the same offset distance as the main contact block 3 from the busbars 2. Figures 3 A - 3C show a second embodiment of the switching gear according to the invention in the same positions as the device shown in figures 2 A - 2C.

The switching gear 20 has again a main contact block 3 and an auxiliary contact block 4, which are linear movable towards the busbars 2 and the contacts 5 respectively.

The operating lever 6 has a shaft 21 with a free end, which is provided with grooves 22. This free end slides in a sleeve 23, which is provided on the outer surface with gear teeth for driving the gear 24. This gear 24 is arranged on a threaded shaft 25 attached to the main contact block 3.

The shaft 21 is furthermore provided with a bearing 26 which is connected by an arm 27 to the auxiliary contact block 4. The bearing 26 ensures that the operating lever 6 can still be rotated despite the connection with the arm 27. The shaft 21 has near the operating lever 6 a switch groove 28, which cooperates with a fixed cam 29. As a result, a switching mechanism is provided which controls, whether the operating lever 6 can be axially moved or can be rotated.

In the position shown in figure 3 A, the operating lever 6 can only be moved axially. By moving the lever 6 axially the free end of the shaft 21 with the grooves 22 is inserted in the sleeve 23 and simultaneously, the auxiliary contact block 4 is brought into connection with the contacts 5, as shown in figure 3B. In the position shown in figure 3B, the cam 29 is positioned in the circumferential groove part of the switch groove 28, such that the operating lever 6 can be rotated. As soon as the axial groove part of the switch groove 28 is no longer aligned with the cam 29, the axial movement of the operating lever 6 is blocked, which ensures that the auxiliary contact block stays connected to the contacts 5.

When the operating lever 6 is rotated, the sleeve 23 will rotate, which in turn rotates the gear 24. The rotation of the gear 24 on the threaded shaft 25 causes the main contact block to move towards the busbars 2, to arrive at the position as shown in figure 3C, in which both the main contact block 3 and the auxiliary contact block 4 are connected to the busbars 2 and the contacts 5 respectively.

By reversing the steps described with respect to figures 3 A - 3C, the main contact block 3 first can be disconnected, after which the auxiliary contact block 4 can be disconnected.

Claims

1. Switching gear comprising:

- a frame;

- a main contact block arranged to the frame and linearly movable between a disconnected position and a connected position;

- an operating lever;

2. Switching gear according to claim 1, wherein the switch mechanism comprises two parts, one part being arranged to the main contact block and one part being arranged to the auxiliary contact block, and a force defined connector for connecting the two parts.

3. Switching gear according to claim 2, wherein the connector comprises a spring means for clamping the two parts of the switch mechanism together.

4. Switching gear according to claim 2 or 3, wherein the connector comprises a magnet for keeping the two parts of the switch mechanism together by magnetic force.

5. Switching gear according to claim 1, wherein one of the main contact block and the auxiliary contact block is moved by the rotation of the operating lever, while the other of the main contact block and the auxiliary contact block is moved by the linear movement of the operating lever, and wherein the switch mechanism comprising blocking means for alternately blocking the linear movement and the rotation of the operating lever.

6. Switching gear according to claim 5, wherein the operating lever comprises at least one longitudinal groove and at least one circumferential groove and at least one cam arranged to the frame running in the grooves, such that when the cam is in the longitudinal groove, the operating lever can only be linearly moved, and when the cam is in the circumferential groove, the operating lever can only be rotated.

7. Switching gear according to any of the preceding claims, wherein the operating lever is connected to the main contact block by a threaded portion, such that the main contact block is moved by rotating the operating lever.