DESC:Assembly of Modular Changeover Contactors with Interlocking Arrangement for Switching Devices

Field of the invention

The present invention relates to electrical switches and more particularly, to an assembly of modular changeover contactors with an interlocking arrangement for a switching device.

Background of the invention

In the prior art it is generally known that the opening of an electrical circuit is achieved when both contactors/ contact systems of a switching device are in OFF positions while closing is achieved when the contactors are in ON positions. The current technology uses two different electromagnets for switching ON of the contactors. Further, each of the contactor uses separate interlocks to prevent simultaneous switching ON of both the contactors. The use of two electromagnets and interlocks increases the overall cost of the switching device. Further, the contactors in the art are designed as a single unit or as 2 pole, 3 pole and 4 pole products that adopt different designs requiring huge investment for individual product development.

Accordingly, there is a need for an assembly of modular changeover contactors with an interlocking arrangement for a switching device that overcomes the drawbacks of the prior art.

Objects of the invention

An object of the present invention is to provide contactors that are capable of adapting to a design with any number of poles thereby providing a simple, cost-effective and reliable solution in choosing contactors for varied applications.
Another object of the present invention is to provide a common actuating means for both the contactors.

Yet another object of the present invention is to integrate the contactors as a single unit with an in-built interlock.

Summary of the invention

Accordingly, the present invention provides an assembly of modular changeover contactors with an interlocking arrangement for a switching device. The assembly comprises a first contactor, a second contactor, a changeover mechanism and an electromagnetic system. The first contactor is integrated with the second contactor to form a single integrated unit of the contactors. The first contactor includes a first contact bridge, a first fixed contact and a first moving contact. The second contactor includes a second contact bridge, a second fixed contact and a second moving contact. The moving contacts are in contact with the contact bridges (5, 15) and capable of separating from or engaging with the fixed contacts in OFF and ON positions of the contactors.

The changeover mechanism is coupled to the second contact bridge by a pin to enable pole-wise modularity and to prevent simultaneous switching ON of both the contactors. The electromagnetic system is coupled to the changeover mechanism by a coupler link.

The electromagnetic system includes a fixed magnet, a moving magnet and a suspension of springs. The suspension of springs is connected to the moving magnet. The moving magnet is actuated by a coil supply upon receiving a signal from any of one of the contactors in ON position.

The actuation of the moving magnet in ON position of the first contactor causes anti-clockwise rotations of the changeover mechanism and upward movement of the first contact bridge thereby actuating the first moving contact to engage with the first fixed contact. The actuation of the moving magnet in ON position of the second contactor causes clockwise rotations of the changeover mechanism and downward movement of the second contact bridge thereby actuating the second moving contact to engage with the second fixed contact.

Brief description of drawings

Other features as well as the advantages of the invention will be clear from the following description.
In the appended drawings:

Figure 1 shows a perspective view of an assembly of modular changeover contactors with an interlocking arrangement for a switching device, in accordance with the present invention;

Figure 2 shows a front view of contactors in OFF position, in accordance with the present invention;

Figure 3 shows a side view of the contactors in OFF position, in accordance with the present invention;

Figure 4 shows a side view of a first contactor in ON position, in accordance with the present invention; and

Figure 5 shows a side view of a second contactor in ON position, in accordance with the present invention.

Detailed description of the invention

The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiment.

The present invention provides an assembly of modular changeover contactors with an interlocking arrangement for a switching device. The assembly integrates two modular changeover contactors as a single unit with an in-built interlocking mechanism and a common actuating means. The assembly enables achieving pole-wise modularity for the contactors and prevents simultaneous switching ON of the contactors.

The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures.

Referring to figures 1-5, an assembly (100) of modular changeover contactors with an interlocking arrangement for a switching device (not shown) in accordance with the present invention is shown. The assembly (100) comprises a first contactor/ a first contact system (not numbered), a second contactor/ a second contact system (not numbered), a changeover mechanism (60) and an electromagnetic system (not numbered).

The first contactor is positioned on a top (not shown) of the switching device. The first contactor includes a first contact bridge (5), a first fixed contact (10) and a first moving contact (20). The second contactor includes a second contact bridge (15), a second fixed contact (30) and a second moving contact (40). The first contactor and the second contactor are in mutual integration with each other. However, the contactors are capable of being converted into a stand-alone single contactor by removing the first contactor from the top of the switching device. Specifically, the contactors are changeover contactors for use in changeover applications such as in a diesel-generator set where the switching between sources is required.

The contactors are capable of switching between ON and OFF positions. The contactors are in OFF position when a coil supply is switched OFF. A supply-1 switches ON the first contactor and a supply-2 switches ON the second contactor by energizing a coil (not shown). The selection of the contactors based on supplies takes place by a separate solenoid actuation (not shown).

The moving contacts (20, 40) are in contact with respective contact bridges (5, 15). The moving contacts (20, 40) are capable of separating from or engaging with the fixed contacts (10, 30) in OFF and ON positions of the contactors. In other words, when the contactors are in OFF positions, the moving contacts (20, 30) are separated from the respective fixed contacts (10, 30) by a gap as shown in figure 3. When the contactors are in ON positions, the moving contacts (20, 30) are actuated to move towards the respective fixed contacts (10, 30) to establish an electrical connection therewith as shown in figures 4 and 5.

The contact bridge (5/15) is capable of moving vertically in response to the switching ON of the respective contactors. Specifically, the first contact bridge (5) moves vertically in upward direction when the first contactor is in ON position. Similarly, the second contact bridge (15) moves vertically in downward direction when the second contactor is in ON position.

The changeover mechanism (60) is positioned between the contactors in a way to connect to the second contact bridge (15) of the second contactor by a pin (55) to enable pole-wise modularity. Each pole (not shown) is a single cassette that is assembled together with the changeover mechanism (60) in a separate module using the pin (55). In an embodiment, the changeover mechanism (60) is an electro-mechanical mechanism. The changeover mechanism (60) helps in achieving the interlocking between the contactors thereby preventing simultaneous switching ON of both the contactors.

When the contactors are connected to two different power supplies, the changeover mechanism (60) shifts from one contactor to the other contactor based on the coil supply thereby switching ON only one of the two contactors. The changeover mechanism (60) is capable of undergoing rotations in any of a clockwise direction and an anti-clockwise direction in response to the switching ON of the contactors. The changeover mechanism (60) rotates in the anti-clockwise direction when the first contactor is in ON position and rotates in the clockwise direction when the second contactor is in ON position.

The electromagnetic system is coupled to the changeover mechanism (60) by a coupler link (65) for example a slider crank mechanism. The electromagnetic system includes a fixed magnet (70), a moving magnet (80) and a suspension of springs (not shown). Specifically, the changeover mechanism (60) couples the moving magnet (80) to the second contact bridge by the pin (55). The suspension of springs is connected to the moving magnet (80). The fixed magnet (70) and the moving magnet (80) are separated from each other when the contactors are in OFF positions. The moving magnet (80) is actuated by the coil supply upon receiving a signal from any of one of the contactors in ON position.

In ON position of any of the contactors, the moving magnet (80) is attracted towards the fixed magnet (70) when the coil is energized. The actuation of the moving magnet (80) results in a series of events that ultimately results in actuation of the moving contact (20/40) for engagement with the fixed contact (10/30) thereby allowing the electrical circuit to remain closed. When the coil supply is switched OFF, the first contactor and the second contactor are in OFF condition such that the moving contacts (20, 40) remain separated from the fixed contacts (10, 30) by the gap to open an electrical circuit thereby disrupting the current flow as shown in figure 3. In the OFF position of the contactors, the entire assembly (100) enters in a stable state by the suspension of springs connected to the moving magnet (80). When the coil supply is ON, the interlocking mechanism (60) allows any one of the contactors to switch ON to keep the electrical circuit closed.

In one aspect, the first contactor is in ON position (refer to figure 4) and the coil actuates the moving magnet (80). The moving magnet (80) moves towards the fixed magnet (70) by means of the suspension of springs causing the changeover mechanism (60) to undergo anti-clockwise rotation and the first contact bridge (5) to move in the upward direction. As a result, the first moving contact (20) being in connection with the first contact bridge (5) actuates and moves to engage with the first fixed contact (10).

In another aspect, the second contactor is in ON position (refer to figure 5) and the coil actuates the moving magnet (80). The moving magnet (80) moves towards the fixed magnet (70) by means of the suspension of springs causing the changeover mechanism (60) to undergo clockwise rotation and the second contact bridge (15) to move in the downward direction. As a result, the second moving contact (40) being in connection with the second contact bridge (15) actuates and moves to engage with the second fixed contact (30). Thus, the changeover mechanism (60) prevents both the contactors from simultaneous switching ON in order to close the electrical circuit.

Advantages of the invention

1. The assembly (100) prevents simultaneous switching ON of the first contactor and the second contactor.
2. The assembly (100) facilitates pole-wise modularity in the contactors thereby deriving 2 pole, 3 pole and 4 pole designs of the contactors.
3. The assembly (100) is compact as the first contactor and the second contactor are integrated as a single unit with the in-built changeover mechanism (60) therebetween.
4. The assembly (100) uses common electromagnetic system for the first contactor and the second contactor.
5. The assembly (100) provides low cost and reliable changeover contactors with minimal investment to market for varied applications like the diesel-generator set.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.

,CLAIMS:We claim:

1. An assembly (100) of modular changeover contactors with an
interlocking arrangement for a switching device, the assembly (100) comprising:
• a first contactor and a second contactor, the first contactor having a
first contact bridge (5), a first fixed contact (10) and a first moving contact (20), the second contactor having a second contact bridge (15), a second fixed contact (30) and a second moving contact (40), the moving contacts (20, 40) being in contact with the contact bridges (5, 15) and being capable of separating from or engaging with the fixed contacts (10, 30) in OFF and ON positions of the contactors, wherein the first contactor is integrated with the second contactor to form a single integrated unit of the contactors;
• a changeover mechanism (60) coupled to the second contact bridge
(15) by a pin (55) thereby enabling pole-wise modularity and preventing simultaneous switching ON of both the contactors; and
• an electromagnetic system coupled to the changeover mechanism (60)
by a coupler link (65), the electromagnetic system having a fixed magnet (70), a moving magnet (80) and a suspension of springs connected to the moving magnet (80), the moving magnet (80) being capable of actuating by a coil supply upon receiving a signal from any of one of the contactors in ON position,
wherein, the actuation of the moving magnet (80) in ON position of the first contactor causes anti-clockwise rotations of the changeover mechanism (60) and upward movement of the first contact bridge (5) thereby actuating the first moving contact (20) to engage with the first fixed contact (10), and the actuation of the moving magnet (80) in ON position of the second contactor causes clockwise rotations of the changeover mechanism (60) and downward movement of the second contact bridge (15) thereby actuating the second moving contact (40) to engage with the second fixed contact (30).